Kubota KX057-4 Service Manual
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James HoynackiKubota KX057-4 Service Manual
Uploaded by
James HoynackiWORKSHOP MANUAL
KUBOTA EXCAVATOR
KX057-4,U55-4
Minor Change version
Serial Number : From 25001
KiSC issued 04, 2021 A
CONTENTS
TO THE READER SERVICING
TO THE READER 1. PUMP......................................................... 3-S1
I INFORMATION 2. CONTROL VALVE..................................... 3-S5
CONTENTS 3. SWIVEL MOTOR ....................................... 3-S9
INFORMATION 4. SWIVEL JOINT ........................................ 3-S23
1. SAFETY FIRST ............................................ I-1 5. TRAVEL MOTOR..................................... 3-S29
2. IN THE INTEREST OF WORK 6. HYDRAULIC CYLINDER ......................... 3-S61
SAFETY........................................................ I-2 7. PILOT VALVE (CONTROL) ..................... 3-S74
3. SAFETY DECALS ........................................ I-6 8. PILOT VALVE (TRAVEL)......................... 3-S83
4. MAIN SPECIFICATIONS............................ I-13 9. PILOT VALVE (SWING) .......................... 3-S94
5. DIMENSIONS ............................................. I-15 10. PILOT VALVE (BLADE)......................... 3-S102
11. UNLOAD VALVE ................................... 3-S109
G GENERAL
12. TPSS VALVE ......................................... 3-S114
CONTENTS
13. THIRD LINE VALVE ASSEMBLY .......... 3-S116
GENERAL
14. ROUTING OF HYDRAULIC HOSES ..... 3-S118
1. CHECKING EXCAVATOR
15. HYDRAULIC DEVICE
IDENTIFICATION ........................................G-1
PERFORMANCE MEASUREMENT ...... 3-S152
2. ENGINE IDENTIFICATION .........................G-2
16. CHART OF MEASURED VALUES
3. MUFFLER FULL ASSEMBLY
FOR HYDRAULIC DEVICE
IDENTIFICATION ........................................G-5
PERFORMANCE ................................... 3-S170
4. GENERAL PRECAUTIONS.........................G-7
17. TROUBLESHOOTING........................... 3-S177
5. HANDLING PRECAUTIONS FOR
ELECTRICAL PARTS AND WIRING.........G-11 4 ELECTRICAL SYSTEM
6. TYPES OF OIL ..........................................G-15 CONTENTS
7. TIGHTENING TORQUES..........................G-16 SERVICING
8. MAINTENANCE.........................................G-21 1. READING THE ELECTRICAL
CIRCUIT DIAGRAMS ................................ 4-S1
1 MACHINE BODY
2. LAYOUT OF ELECTRICAL
CONTENTS
EQUIPMENT AND CONNECTORS .......... 4-S8
SERVICING
3. TROUBLESHOOTING (START-UP
1. FRONT OPERATING MACHINE............... 1-S2
EQUIPMENT VERSION) ......................... 4-S19
2. SWIVEL FRAME........................................ 1-S7
4. INSPECTIONS......................................... 4-S20
3. TRACK FRAME ....................................... 1-S34
5. INSTRUMENT PANEL OPERATING
2 ENGINE GUIDE...................................................... 4-S26
CONTENTS 6. TROUBLESHOOTING (METER
GENERAL PANEL EDITION) .................................... 4-S89
1. SPECIFICATIONS.....................................2-G1 7. DEALER SETTING MODE
2. EXTERNAL DIMENSIONS ........................2-G2 FLOWCHART ............................................ 4-S1
3. LAYOUT OF MAIN PARTS .......................2-G3
5 CABIN
4. PERFORMANCE CURVE .........................2-G4
CONTENTS
5. FAN DRIVE................................................2-G5
MECHANISM
3 HYDRAULIC SYSTEM 1. AIR CONDITIONING SYSTEM................. 5-M1
CONTENTS 2. WIPER .................................................... 5-M20
MECHANISM SERVICING
1. DIAGRAM OF HYDRAULIC CIRCUIT 1. TROUBLESHOOTING............................... 5-S1
[KX057-4, U55-4 STANDARD 2. MAINTENANCE AND
SPECIFICATION (ANGLE BLADE SERVICE RELATED SPECIFICATIO
OPTION)].................................................. 3-M1 NS .............................................................. 5-S4
2. HYDRAULIC DEVICE LAYOUT ............... 3-M1 3. TORQUE.................................................... 5-S5
3. PUMP ....................................................... 3-M2 4. PRECAUTIONS WHEN REPAIRING
4. CONTROL VALVE.................................. 3-M13 THE REFRIGERANT SYSTEM ................. 5-S6
5. SWIVEL MOTOR.................................... 3-M24 5. INSPECTING AND CHARGING THE
6. TRAVEL MOTOR ................................... 3-M30 REFRIGERANT SYSTEM ....................... 5-S11
7. HYDRAULIC CYLINDER........................ 3-M40 6. INSPECTION AND DISASSEMBLY ........ 5-S20
8. PILOT VALVE......................................... 3-M48 7. CABIN REMOVAL AND MOUNTING ...... 5-S39
9. UNLOAD VALVE .................................... 3-M63 8. WINDOW WASHER ................................ 5-S41
10. SOLENOID VALVE................................. 3-M67 9. LIGHTING DEVICES (CAB WORK
LIGHT, INTERIOR LIGHT) ...................... 5-S45
KiSC issued 04, 2021 A
10. REMOVAL AND INSTALLATION OF
GLASS ..................................................... 5-S48
11. FRONT WINDOW .................................... 5-S53
KiSC issued 04, 2021 A
TO THE READER
This Workshop Manual provides service personnel with information about the mechanisms, service
and maintenance of the construction machinery. This Workshop Manual is divided into 3 sections,
General, Mechanisms and Service.
General
This section contains information such as engine and equipment ID numbers, general precautions,
maintenance schedules, inspections and maintenance items and special tools.
Mechanisms
This section describes the structure of mechanisms and explains their functions. Be sure that you
fully understand this Mechanisms section prior to performing any service work, such as troubleshooting
or when performing any disassembly or assembly work.
Service
This section contains information and procedures for performing maintenance on the backhoe, such
as troubleshooting, service specification tables, torque specifications, items to be inspected and
adjusted, disassembly and assembly procedures, as well as precautions, maintenance standard values
and usage limits.
All of the illustrations, specifications and other information in this manual were created based on the
latest model at the time of publication.
Please be aware that changes to the content may be made without prior notice.
NOTE
• Corresponding model list
Machine Model Engine Model
KX057-4
V2607-CR-E4-BH
U55-4
IMPORTANT
• Refer to the following "Workshop Manual" for the engine information.
Workshop Manual Model:
Diesel Engine V2607-CR-E4B, V2607-CR-TE4B, V3307-CR-TE4B
WEB PDF No.: 9Y111-06740
Hard Copy No.: 9Y121-06740
CD-ROM No.: 9Y131-06740
February, 2013
© KUBOTA Corporation 2013
KiSC issued 04, 2021 A
Record of Revisions
Last digit
of the Date Page Main Revised Point and Corrective Measures Remarks
Code No.
• Description of PM clog level and the state of the
1 2013.07.01 4-S85 to 4-S88 H.M
Machine added.
• Changed the lubrication oil of the carrier roller to
G-15
grease from the engine oil.
2 2017.09.04 R.T
• Changed the fuel hose routing according to
1-S12 to 1-S14
adding filter function to the water separator.
4-S44 • Corrected the Water temperature voltage in the
3 2021.04 H.M
R-1 Tester List.
KiSC issued 04, 2021 A
I INFORMATION
KiSC issued 04, 2021 A
INFORMATION
CONTENTS
1. SAFETY FIRST .............................................................................................................................. I-1
2. IN THE INTEREST OF WORK SAFETY ........................................................................................ I-2
[1] WORKING SAFELY WITH THE EQUIPMENT MEANS ALWAYS FOLLOWING
THESE INSTRUCTIONS:......................................................................................................... I-2
(1) Precautions Before Working on the Mini-Excavator ........................................................... I-2
(2) Precautions Before Working on the Equipment.................................................................. I-3
3. SAFETY DECALS .......................................................................................................................... I-6
[1] US, CA VERSION .................................................................................................................... I-6
4. MAIN SPECIFICATIONS.............................................................................................................. I-13
5. DIMENSIONS ............................................................................................................................... I-15
KiSC issued 04, 2021 A
KX057-4,U55-4, WSM INFORMATION
1. SAFETY FIRST
SAFETY FIRST
• This "Safety Alert Symbol" is used in this manual and on labels on equipment to indicate important
issues and warn of the danger of personal injury. Read and follow these warnings carefully.
• It is important that you thoroughly read these instructions and safety rules prior to working on the
equipment and that you always follow them.
DANGER
• Indicates that failure to follow the warning will result in serious injury or death.
WARNING
• Indicates that failure to follow the warning may result in serious injury or death.
CAUTION
• Indicates that failure to follow the warning may result in injury.
IMPORTANT
• Indicates that failure to follow the warning may result in damage to or a breakdown of the equipment.
NOTE
• Indicates supplementary explanations that will be helpful when using the equipment.
[NOTE]
• Indicates other supplementary information to take note of.
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KX057-4,U55-4, WSM INFORMATION
2. IN THE INTEREST OF WORK SAFETY
[1] WORKING SAFELY WITH THE EQUIPMENT MEANS ALWAYS
FOLLOWING THESE INSTRUCTIONS:
(1) Precautions Before Working on the Mini-Excavator
Before starting any service or maintenance work
• Read all the general and safety instructions in this
manual, as well as the decals on your equipment.
• Always stop the engine whenever you leave the
driver's seat to inspect or clean the machine or its
devices, or to inspect or adjust parts.
• Choose a safe spot for inspecting the equipment-on
flat, hard ground.
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• When performing maintenance on the equipment,
hang the DO NOT OPERATE sign where it will be
obvious from and around the driver's seat.
• When performing maintenance or repairs, always
lower attachments to the ground, stop the engine
and attach the warning sign clearly visible.
• When performing maintenance on the equipment,
always disconnect the negative battery cable.
• Before using tools, make sure you understand how
to use them correctly and use tools in good condition
and of the right size for the job.
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Be Ready for an Emergency
• Keep a first-aid kit and fire extinguisher close at hand
so you can use it when needed.
• Keep emergency contact information for doctors,
hospitals and ERs handy.
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• Wear clothes appropriate for working on equipment.
Do not wear loose-fitting clothes as they may catch
on the machine controls.
• When working on the equipment, use all safety gear,
such as a helmet, safety glasses and shoes, that are
required by law or regulation.
• Never perform maintenance while drowsy or under
the influence of alcohol or drugs.
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(2) Precautions Before Working on the Equipment
• Stop the machine on a hard and level location and
make sure the area around the machine is free of
obstacles and hazardous materials. When parking
the machine indoors, select a spot that can be
properly ventilated.
• When performing work such as with a hammer,
fragments may chipping off, so make sure only
authorized persons are around the machine.
• Before servicing the machine, clean it off so there is
no mud, debris, oil or the like sticking to it.
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• Before getting on/off of the machine, clean off
around the steps so there is no mud on them.
Always give yourself 3-point support when getting
on/off the machine.
CAUTION
• 3-point support means using both legs and one
hand or both hands and one leg as you climb
up/down.
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Starting the Machine Safely
• Before starting the engine, always sit in the driver's
seat and make sure the area is safe and clear.
• As it is dangerous, never start the engine from
anywhere but the driver's seat.
• Always check and make sure control lever(s) are not
engaged before starting the engine.
• Never start the engine by hot-wiring the starter
circuit. This is not only dangerous, but may damage
the machine.
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• Whenever it is necessary to open the engine covers
or bonnet in order to service the machine, always
prop them open.
• If it is absolutely necessary to run the engine while
working on the machine, make sure you are clear of
all rotating or moving parts. Also take care not to
leave anything, such as tools or rags, near any
moving parts.
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KX057-4,U55-4, WSM INFORMATION
• The engine, muffler, radiator, hydraulic line, etc.,
have parts that remain very hot even after the engine
has been stopped. Be sure to avoid these parts, as
touching them can result in burns. Radiator coolant,
hydraulic fluid and oil also remain hot. Therefore, do
not attempt to remove caps and plugs, etc., before
these fluids have sufficiently cooled.
• Make sure the coolant temperature has dropped
sufficiently before opening the radiator cap.
Also, since the inside of the radiator is pressurized,
when removing the cap, first loosen it to release the
pressure before removing the cap completely.
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• The pressure in the hydraulic circuit stays at
pressure even after the engine stops.
Before removing parts, such as hydraulic devices
from the machine, first release the pressure. Please
note that when releasing residual pressure, the
machine itself and/or implements may move without
warning, so be very careful when releasing the
pressure.
• Oil gushing out under pressure is extremely
dangerous as it may pierce your skin or your eyes.
Similarly, oil leaking out of pinholes is not visible.
So when checking for oil leaks, always wear safety
glasses and gloves and use a piece of cardboard or
a wood block to shield yourself from oil.
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No Smoking or Open Flames while Fueling
• Fuel is extremely flammable and dangerous.
Never smoke near fuel. If fuel is spilled on the
machine, its engine, or electrical parts, it may cause
a fire. If fuel is spilled, wipe it all up immediately.
• Never smoke while filling the machine with fuel.
And always tighten the fuel cap securely and wipe up
any spilled fuel.
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• Always wear safety glasses and gloves when
handling the battery.
• The gas generated by the battery is flammable.
Never weld or use tools like a grinder near the
battery. And never smoke near it.
• When disconnecting the battery, always disconnect
the negative cable first. When connecting the
battery, always connect the positive cable first.
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I-4 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM INFORMATION
• Grease is under high pressure inside the hydraulic
cylinder. It is very dangerous to loosen a grease
nipple quickly as it may shoot off. Always loosen
grease nipples slowly.
• And never face a grease nipple while loosening it.
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Dispose of Waste Fluids Properly
• Never dispose of waste fluids on the ground, in the
gutter, a river, pond or lake. Always dispose of
hazardous substances like waste oil, coolant and
electrolytic fluid in accordance with the relevant
environmental protection regulations.
• Keep the safety plates clean so they can be read.
If a safety plate is damaged and comes off or
becomes illegible, put a plate with the same
warnings back in its place.
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I-5 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM INFORMATION
3. SAFETY DECALS
The following safety decals are installed on the machine.
If a decal becomes damaged, illegible or is not on the machine, replace it. The decal part number is listed in
the parts list.
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[1] US, CA VERSION
DANGER, WARNING AND CAUTION LABELS
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KX057-4,U55-4, WSM INFORMATION
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KX057-4,U55-4, WSM INFORMATION
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I-11 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM INFORMATION
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CARE OF DANGER, WARNING AND CAUTION LABELS
1. Keep danger, warning and caution labels clean and free from obstructing material.
2. Clean danger, warning and caution labels with soap and water, dry with a soft cloth.
3. Replace damaged or missing danger, warning and caution labels with new labels from your KUBOTA dealer.
4. If a component with danger, warning and caution label(s) affixed is replace with new part, make sure new label(s)
is (are) attached in the same locations(s) as the replace component.
5. Mount new danger, warning and caution labels by applying on a clean dry surface and pressure any bubbles to
outside edge.
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I-12 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM INFORMATION
4. MAIN SPECIFICATIONS
KUBOTA EXCAVATOR
Model name KX057-4
Angle Blade Type
Type Canopy CAB
Canopy CAB
5535 kg 5625 kg 5725 kg 5815 kg
Operating weight (including operator's)
12200 lbs 12400 lbs 12620 lbs 12820 lbs
Type Water cooled 4 cycle diesel engine with 4 cylinder
Model name (No air conditioner type)
Total displacement V2607-CR-E4-BH1
Engine (Air conditioner type)
Engine power SAE gross V2607-CR-E4-BH2
Rated speed 2200 rpm
Low idle speed 1100 rpm
Unit swing speed 9.3 rpm
Fast 4.9 km/h (3.04 mph)
Travel speed
Slow 2.8 km/h (1.74 mph)
Performance 31.3 kPa 31.9 kPa 32.4 kPa 33.0 kPa
Ground pressure
0.319 kgf/cm2 0.325 kgf/cm2 0.330 kgf/cm2 0.336 kgf/cm2
(With operator)
4.54 psi 4.62 psi 4.69 psi 4.78 psi
Climbing angle 36 % (20 deg)
Angle in case of crossing slope 27 % (15 deg)
1960 × 410 mm 1960 × 425 mm
Blade Width × Height
77.16 × 16.2 in. 77.16 × 16.7 in.
Boom swing Left
Max. swing – 25 deg
angle Right
Max. AUX1 port 75 L/min (20 U.S.gals/min)
Pressure displacement
(Theoretical) Thumb port 37 L/min (9.8 U.S.gals/min)
connection
for AUX1 port 17.2 MPa
attachments Max.
175 kgf/cm2
pressure Thumb port 2500 psi
Fuel tank capacity 75 L (20 U.S.gals)
NOTE
• Above dimensions are based on the machine with QUICK HITCH BUCKET.
• Above dimensions are based on the machine with rubber track.
• Specifications subject to change without notice.
∗ Firm compacted soil.
∗ Operators must exercise extra caution and follow instructions in the operator's manual.
∗ Worse condition or heavier attachment to the above will decrease climbing angle.
• ROPS/FORS structure complies with ISO 3471, ISO 3449 and OSHA regulations.
RY9212166INI0002US0
I-13 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM INFORMATION
KUBOTA EXCAVATOR
Model name U55-4
Angle Blade Type
Type Canopy CAB
Canopy CAB
5405 kg 5495 kg 5595 kg 5685 kg
Operating weight (including operator's)
11915 lbs 12115 lbs 12335 lbs 12535 lbs
Type Water cooled 4 cycle diesel engine with 4 cylinder
Model name (No air conditioner type)
Total displacement V2607-CR-E4-BH1
Engine (Air conditioner type)
Engine power SAE gross V2607-CR-E4-BH2
Rated speed 2200 rpm
Low idle speed 1100 rpm
Unit swing speed 9.3 rpm
Fast 4.9 km/h (3.04 mph)
Travel speed
Slow 2.8 km/h (1.74 mph)
Performance 30.5 kPa 31.1 kPa 31.6 kPa 32.1 kPa
Ground pressure
0.311 kgf/cm2 0.317 kgf/cm2 0.322 kgf/cm2 0.327 kgf/cm2
(With operator)
4.42 psi 4.51 psi 4.58 psi 4.65 psi
Climbing angle 36 % (20 deg)
Angle in case of crossing slope 27 % (15 deg)
1960 × 410 mm 1960 × 425 mm
Blade Width × Height
77.16 × 16.2 in. 77.16 × 16.7 in.
Boom swing Left
Max. swing – 25 deg
angle Right
Max.
Pressure displacement Thumb port 37 L/min (9.8 U.S.gals/min)
connection (Theoretical)
for AUX1 port 17.2 MPa
attachments Max.
175 kgf/cm2
pressure Thumb port 2500 psi
Fuel tank capacity 75 L (20 U.S.gals)
NOTE
• Above dimensions are based on the machine with QUICK HITCH BUCKET.
• Above dimensions are based on the machine with rubber track.
• Specifications subject to change without notice.
∗ Firm compacted soil.
∗ Operators must exercise extra caution and follow instructions in the operator's manual.
∗ Worse condition or heavier attachment to the above will decrease climbing angle.
• ROPS/FORS structure complies with ISO 3471, ISO 3449 and OSHA regulations.
RY9212166INI0003US0
I-14 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM INFORMATION
5. DIMENSIONS
(A) (B) (C) (D) (E) (F) (G) (H) (I) (J)
750 mm 550 mm 1960 mm 5740 mm 4180 mm 3865 mm 1710 mm 1270 mm 4250 mm 6240 mm
KX057-4
29.5 in. 21.7 in. 77.2 in. 226.0 in. 164.6 in. 152.1 in. 67.3 in. 50.0 in. 167.4 in. 245.7 in.
(K) (L) (M) (N) (O) (P) (Q) (R) (K) ANG (L) ANG
440 mm 410 mm 2550 mm 1960 mm 6110 mm 5520 mm 1830 mm 2420 mm 510 mm 465 mm
KX057-4
17.3 in. 16.2 in. 100.4 in. 77.2 in. 240.6 in. 217.4 in. 72.0 in. 95.3 in. 20.0 in. 18.3 in.
(A) (B) (C) (D) (E) (F) (G) (H) (I) (J)
815 mm 625 mm 1960 mm 5580 mm 4020 mm 3615 mm 1515 mm 1045 mm 4310 mm 6080 mm
U55-4
32.1 in. 24.6 in. 77.2 in. 219.7 in. 158.3 in. 142.3 in. 59.65 in. 41.1 in. 169.7 in. 239.4 in.
(K) (L) (M) (N) (O) (P) (Q) (R) (K) ANG (L) ANG
440 mm 410 mm 2550 mm 1960 mm 5945 mm 5500 mm 1830 mm 2460 mm 510 mm 465 mm
U55-4
17.3 in. 16.2 in. 100.4 in. 77.2 in. 234.1 in. 216.5 in. 72.0 in. 96.9 in. 20.0 in. 18.3 in.
NOTE
• Above dimensions are based on the machine with KUBOTA original bucket.
• Above dimensions are based on the machine with rubber track.
• Specifications subject to change without notice.
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I-15 KiSC issued 04, 2021 A
G GENERAL
KiSC issued 04, 2021 A
GENERAL
CONTENTS
1. CHECKING EXCAVATOR IDENTIFICATION .............................................................................. G-1
2. ENGINE IDENTIFICATION .......................................................................................................... G-2
[1] MODEL NAME AND SERIAL NUMBER ................................................................................ G-2
[2] E4B ENGINE .......................................................................................................................... G-4
3. MUFFLER FULL ASSEMBLY IDENTIFICATION ......................................................................... G-5
[1] PART NUMBER AND SERIAL NUMBER .............................................................................. G-5
4. GENERAL PRECAUTIONS.......................................................................................................... G-7
5. HANDLING PRECAUTIONS FOR ELECTRICAL PARTS AND WIRING .................................. G-11
[1] WIRING ................................................................................................................................ G-11
[2] FUSES.................................................................................................................................. G-13
[3] CONNECTOR ...................................................................................................................... G-13
[4] WASHING THE MACHINE WITH A HIGH-PRESSURE WASHER ..................................... G-14
6. TYPES OF OIL ........................................................................................................................... G-15
[1] TABLE OF OIL AND FLUID CAPACITIES ........................................................................... G-15
[2] CHECKING AND FILLING HYDRAULIC OIL ....................................................................... G-15
7. TIGHTENING TORQUES........................................................................................................... G-16
[1] GENERAL USE SCREWS, BOLTS AND NUTS .................................................................. G-16
[2] STUD BOLTS ....................................................................................................................... G-16
[3] TORQUE FOR HYDRAULIC HOSE FITTINGS ................................................................... G-17
(1) Torque for Hydraulic Hose Fittings ................................................................................. G-17
(2) Torques of Lock-Nuts for Elbows with Male Seats and Adaptors with O-Rings
(Straight Threads)........................................................................................................... G-18
(3) Torque for Tapering Adaptors ........................................................................................ G-18
[4] HOSE CLAMP SCREW TORQUE ....................................................................................... G-19
8. MAINTENANCE.......................................................................................................................... G-21
KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
1. CHECKING EXCAVATOR IDENTIFICATION
When consulting with your local KUBOTA dealer about this
mini-excavator, please provide the model of the mini-excavator, its
frame and engine numbers and the number of hours on the hour
meter.
(1) Mini-Excavator Nameplate (a) Model Nameplate
(Model, Frame Number, Engine
Number)
(2) Frame Number
(3) Engine Number
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KX057-4,U55-4, WSM GENERAL
2. ENGINE IDENTIFICATION
[1] MODEL NAME AND SERIAL NUMBER
Be sure to check the engine nameplate and serial number when
you wish to consult about the engine.
The model and serial number of the engine need to be checked
prior to servicing the engine or replacing any of its parts.
Engine Serial No.
The engine serial number is the numerical ID of the engine and
is printed after the engine's model number.
The year and month of manufacture are indicated as follows.
Engine Series
Number or Number or
Series Series
Alphabet Alphabet
GZ, OC, AC, EA,
1 05 (include: WG) 6
E
2 V3 7 03
3 08 8 07
4 SM (include: WG) A EA, RK
Air Cooled 03 (KET
5 B
Gasoline Production)
Production Year
Alphabet or Alphabet or
Year Year
Number Number
1 2001 F 2015
2 2002 G 2016
3 2003 H 2017
4 2004 J 2018
5 2005 K 2019
6 2006 L 2020
7 2007 M 2021
8 2008 N 2022
9 2009 P 2023
A 2010 R 2024
B 2011 S 2025
C 2012 T 2026
D 2013 V 2027
E 2014
(1) Engine Model Name and Serial
Number
(To be continued)
G-2 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
(Continued)
Production Month and Lot Number
Month Engine Lot Number
January A0001 to A9999 from B0001
February C0001 to C9999 from D0001
March E0001 to E9999 from F0001
April G0001 to G9999 from H0001
May J0001 to J9999 from K0001
June L0001 to L9999 from M0001
July N0001 to N9999 from P0001
August Q0001 to Q9999 from R0001
September S0001 to S9999 from T0001
October U0001 to U9999 from V0001
November W0001 to W9999 from X0001
December Y0001 to Y9999 from Z0001
* Alphabetical letters "I" and "O" are not used.
(a) (b)(c)(d) (e)
e.g. V2607 - 8 C L A001
(a) V2607: Engine Model Name
(b) 8: Engine Series (07 series)
(c) C: Production Year (2012)
(d) L: Production Month (June)
(e) A001: Lot Number: (0001 to 9999 or A001 to Z999)
RY9212166GEG0005US0
G-3 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
[2] E4B ENGINE
[Example: Engine Model Name V2607-CR-E4B-XXXX]
The emission controls previously implemented in various countries to prevent air pollution will be stepped up as
Nonroad Emission Standards continue to change. The timing or applicable date of the specific Nonroad Emission
regulations depends on the engine output classification.
Over the past several years, KUBOTA has been supplying diesel engines that comply with regulations in the
respective countries affected by Nonroad Emission regulations. For KUBOTA Engines, E4B will be the designation
that identifies engine models affected by the next emission phase (See the table below).
When servicing or repairing ###-E4B series engines, use only replacement parts for that specific E4B engine,
designated by the appropriate E4B KUBOTA Parts List and perform all maintenance services listed in the appropriate
KUBOTA Operator's Manual or in the appropriate E4B KUBOTA Workshop Manual. Use of incorrect replacement
parts or replacement parts from other emission level engines (for example: E3B engines), may result in emission
levels out of compliance with the original E4B design and EPA or other applicable regulations. Please refer to the
emission label located on the engine head cover to identify Output classification and Emission Control Information.
E4B engines are identified with "EF" at the end of the Model designation, on the US EPA label. Please note: E4B is
not marked on the engine.
Category (1) Engine output classification EU regulation
P From 37 to less than 56 kW STAGE IIIB
N From 56 to less than 75 kW STAGE IIIB
M From 75 to less than 130 kW STAGE IIIB
Category (2) Engine output classification EPA regulation
Less than 19 kW Tier 4
From 19 to less than 56 kW Interim Tier 4
EF
From 56 to less than 75 kW Interim Tier 4
From 75 to less than 130 kW Interim Tier 4
(1) EU Regulation Engine Output Classification Category
(2) "E4B" Engines are Identified with "EF" at the End of the Model Designation, on
the US EPA Label.
"E4B" Designates some Interim Tier 4 / Tier 4 Models, Depending on Engine
Output Classification.
RY9212166GEG0006US0
You can see the cylinder numbers of KUBOTA diesel engine in
the figure.
The sequence of cylinder numbers is No.1, No.2, No.3 and No.4
and it starts from the front cover side.
RY9212166GEG0007US0
G-4 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
3. MUFFLER FULL ASSEMBLY IDENTIFICATION
[1] PART NUMBER AND SERIAL NUMBER
Diesel Particulate Filter (hereinafter referred to as the "DPF")
Muffler Full Assembly Serial Number
The DPF muffler full assembly serial number is an identified
number for the DPF muffler full assembly.
It shows the month and year of manufacture as below.
Year of manufacture
Alphabet or Alphabet or
Year Year
Number Number
1 2001 F 2015
2 2002 G 2016
3 2003 H 2017
4 2004 J 2018
5 2005 K 2019
6 2006 L 2020
7 2007 M 2021
8 2008 N 2022
9 2009 P 2023
A 2010 R 2024
B 2011 S 2025
C 2012 T 2026
D 2013 V 2027
E 2014
Month of manufacture
Month DPF Muffler Full Assembly Lot Number
January A0001 to A9999 B0001 to BZ999
February C0001 to C9999 D0001 to DZ999
March E0001 to E9999 F0001 to FZ999
April G0001 to G9999 H0001 to HZ999
May J0001 to J9999 K0001 to KZ999
June L0001 to L9999 M0001 to MZ999
July N0001 to N9999 P0001 to PZ999
August Q0001 to Q9999 R0001 to RZ999
September S0001 to S9999 T0001 to TZ999
October U0001 to U9999 V0001 to VZ999
November W0001 to W9999 X0001 to XZ999
December Y0001 to Y9999 Z0001 to ZZ999
* Alphabetical letters "I" and "O" are not used.
(a)(b) (c)
e.g. B L 0019
(1) DPF Muffler Full Assembly Part Number and Serial Number
(a) Year: B Indicates 2011
(b) Month: L or M Indicates June
(c) Lot Number: (0001 to 9999 or A001 to Z999)
RY9212166GEG0008US0
G-5 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
Diesel Particulate Filter (hereinafter referred to as the "DPF")
Muffler Full Assembly Serial Number
You must keep the records of the filter comp (DPF) part number
and serial number (3) and catalyst (DOC) part number and serial
number (4) before you remove the DPF for cleaning.
(1) DPF Muffler Assy Part Number and (A) V2607-CR-E4B
Serial Number (B) V2607-CR-TE4B
(2) DPF Muffler Full Assy Part Number V3307-CR-TE4B
and Serial Number
(3) Filter Comp (DPF) Part Number and
Serial Number
(4) Catalyst (DOC) Part Number and
Serial Number
RY9212166GEG0009US0
G-6 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
4. GENERAL PRECAUTIONS
Whenever performing maintenance on the machine, always
read the Safety Precautions in this manual and the Operator's
Manual carefully, become familiar with them and perform the work
safely.
Before performing any maintenance on the machine, make sure
it is sufficiently clean and choose a sufficiently clean location to
perform any disassembly.
Before performing maintenance on the machine, always
disconnect the negative battery cable first.
Whenever a special tool is required, use the special tool that
KUBOTA recommends. Make any special tools that are not used
very frequently according to the diagrams in this manual.
Always use genuine KUBOTA parts to maintain the
performance and safety characteristics of the machine.
RY9212001GEG0011US0
Plumber's Tape
• Wrap plumber's tape on the threads before tightening taper
couplings. After wrapping (2 wraps) the plumber's tape, tighten
to the specified torque. Once the coupling is tightened, do not
loosen it as this will cause an oil leak.
(1) Plumber's Tape (4) Gap
(2) External Thread (5) Leave 1 to 2 Threads
(3) Internal Thread
RY9212001GEG0012US0
O-Ring
• Clean the groove the O-ring goes in and remove any burrs.
Apply grease on the O-ring when inserting it in the groove
(Except floating seals).
• When putting the O-ring in the groove, be careful as it is easy at
the very end to twist the O-ring against the inside of the groove.
If it gets twisted, roll it gently with your fingertip to untwist it.
(1) O-Ring Groove (4) If the Ring Touches This Corner, It
(2) O-Ring Will Twist
(3) Check for Burrs
RY9212001GEG0013US0
Oil Seal
• Do not face the lip of the oil seal in the wrong direction. Face the
main lip toward the material to be sealed.
• After oil seals are replaced, apply grease to the moving parts
around the lip to prevent the dry surfaces from wearing against
each other when the engine is started. If the seal has a dust lip,
fill the gap between the lips with grease.
• As a general rule, use a press to insert the oil seal in place.
If that is not possible, use an appropriate tool to gently and
evenly tap it into place, taking care that it does not go in at a
slant. Press the seal all the way so it seats in the boss.
(1) Gasket A : Air (Outside)
(2) Metal Ring B : Hydraulic Chamber (Inside)
(3) Spring
(4) Main Lip
(5) Grease
(6) Dust Lip
RY9212001GEG0014US0
G-7 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
Floating Seal
• Be sure to wipe off any oil from the O-ring or surfaces that touch
the O-ring (For wheel motors, apply a light film).
• When putting an O-ring into a floating seal, make sure the
O-ring does not twist.
• Apply a light film of oil to surrounding surfaces when working to
get the floating seal with O-ring in place; take care that the
surrounding surfaces, O-ring and housing are parallel with each
other.
• After getting the seal in place, turn the engine over 2 or 3
revolutions, to both create a film of oil on surrounding surfaces
and to properly seat the face of the seal.
(1) Surrounding Surfaces (2) O-Ring
RY9212001GEG0015US0
Snap Ring Related
• When installing external or internal snap rings, orient them as
shown in the diagram so the angled side faces the direction of
force.
(1) Position so the Angled Part (A) External
Receives the Force (B) Internal
RY9212001GEG0016US0
Spring Pins
• When driving a spring pin, face the split in the direction that
receives the force, as shown in the diagram.
(1) With Lateral Movement (2) With Rotational Movement
RY9212001GEG0017US0
Adhesive
• Clean and dry the area where adhesive will be applied with a
solvent so it is free of moisture, oil and dirt.
• Apply adhesive all around the threads of the bolt except the first
set of threads at the tip and fill the grooves between the threads.
If the threads or the grooves are large, adjust the amount of
adhesive accordingly and apply it all around the bolt hole as
well.
(A) Bolt Through-Hole (Nut) (a) Apply Here
(B) Pocket Bolt Hold (b) Do Not Apply
(Capsule Shape, etc.) (c) Drip On
RY9212001GEG0018US0
G-8 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
Tightening Bolts and Nuts
• Tighten bolts and nuts to their specified torque.
• Tighten nuts and bolts alternately top/bottom (a) (b), left/right so
the torque is distributed evenly.
(A) Top/Bottom Alternately (C) Diagonally Across the Center
(B) Across Diagonally
RY9212001GEG0019US0
Assembling Hydraulic Hoses
• Tighten to their specified torque.
• Before assembling, wipe the inside of metal fittings clean of any
dirt.
• After assembly, put the fitting under normal pressure and check
that it does not leak.
RY9212001GEG0020US0
Elbow with Male Seat Assembly Procedure
When assembling an elbow with male seat, adhere to the
following procedures to prevent deformation of O-rings and leaks.
1. Connecting to Valves
• Clean the blow with male seat and the surface of the seal
opposite and mount with the lock-nut on top.
• Finger tighten till it touches the washer.
2. Positioning
• Turn the mouth of the elbow back so it faces the right
direction (not back over 1 turn).
3. Fasten
• Tighten the lock-nut to the specified torque with a wrench.
(1) Lock-Nut (4) Wrench for Holding
(2) Washer (5) Hose
(3) Seal (O-Ring) (6) Torque Wrench for Tightening
RY9212001GEG0021US0
G-9 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
Installing and Removing Quick Couplings
• To remove a quick hose coupling, push the fitting in the direction
of the arrow and pull on the plastic part in the opposite direction.
• To attach a quick coupler, push it in firmly in the direction of the
arrow. Then check that it will not pull off.
(1) Plastic Part (2) Fitting
RY9212001GEG0022US0
G-10 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
5. HANDLING PRECAUTIONS FOR ELECTRICAL
PARTS AND WIRING
Follow the precautions below for handling electrical parts and
wiring to ensure safety and prevent damage to the machine and
nearby equipment.
IMPORTANT
• Inspect electrical wiring for damage and/or loose
connections.
• Do not alter or rewire any electrical parts or wiring.
• Always remove the negative battery cable first when
disconnecting the battery and attach the positive cable first
when connecting it.
(1) Battery Cable (-) Side (2) Battery Cable (+) Side
RY9212001GEG0023US0
[1] WIRING
• Tighten wiring terminals securely.
(1) Correct (Tightened Securely) (2) Incorrect (Poor Contact if Loose)
RY9212001GEG0024US0
• Keep wiring away from hazards.
(1) Hazardous Positioning (3) Wiring Position (Right)
(2) Wiring Position (Wrong) (4) Hazardous Position
RY9212001GEG0025US0
• Immediately repair or replace old or damaged wiring.
(1) Damaged (3) Electrical Tape
(2) Torn
RY9212001GEG0026US0
G-11 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
• Insert grommet securely.
(1) Grommet (A) Correct
(B) Incorrect
RY9212001GEG0027US0
• Clamp wiring securely but do not damage wires with the clamp.
(1) Clamp (Spiral Clamp Around Wire) (3) Clamp
(2) Wire (4) Welding Mark
RY9212001GEG0028US0
• Clamp wiring so it is not twisted, pulled too tight or sag too
much. However, moving parts may require play in the wiring.
(1) Wire (A) Correct
(2) Clamp (B) Incorrect
RY9212001GEG0029US0
• Do not pinch or bind wiring when installing parts.
(1) Wire (A) Incorrect
RY9212001GEG0030US0
• After wiring, double-check terminal protectors and clamps
before connecting battery cables.
(1) Cover (Install Covers Securely)
RY9212001GEG0031US0
G-12 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
[2] FUSES
• Always use fuses of the specified capacity.
Never use over or undersized fuses.
• Never use copper or steel wire in place of a fuse.
• Do not install accessories such as work lights, radios, etc., if
your machine does not have an auxiliary circuit.
• Do not install accessories as they will exceed the capacity of
fuses.
(1) Fuse (3) Slow-Blow Fuse
(2) Fusible Link
RY9212001GEG0032US0
[3] CONNECTOR
• Press the lock to disconnect locking connectors.
(A) Push
RY9212001GEG0033US0
• Hold the connectors when separating them.
• Do not pull on the wire harness to separate the connectors.
(A) Correct (B) Incorrect
RY9212001GEG0034US0
• Straighten bent prongs and make sure none are sticking out or
missing.
• Remove corrosion from terminals with sandpaper.
(1) Missing Terminal (3) Sandpaper
(2) Bent Prong (4) Corrosion
RY9212001GEG0035US0
• Female connectors must not be spread too far open
(A) Correct (B) Incorrect
RY9212001GEG0036US0
G-13 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
• The plastic covers of connectors must cover them completely.
(1) Cover (A) Correct
(B) Incorrect
RY9212001GEG0037US0
[4] WASHING THE MACHINE WITH A HIGH-PRESSURE WASHER
Using a high-pressure washer incorrectly can lead to personal
injury and/or damage, break or cause parts of the machine to fail,
so use the power washer properly according to its operator's
manual and labels.
CAUTION
• Stand at least 2.0 meters from the machine and adjust the
nozzle for a wide spray so it does not cause any damage.
If you blast the machine with water or wash it from too
close a distance,
1. It may cause a fire due to damaged or cuts in the insulation
of electrical wiring.
2. An injury may result if hydraulic oil gushes out under high
pressure, due to damaged hydraulic hoses.
3. It may damage, break or cause parts of the machine to fail.
(E.g.)
(1) Stickers or labels may come off
(2) Electrical parts or the engine may fail due to water in them.
(3) Damage glass, resins, etc. or the rubber of oil seals.
(4) Tear off paint or the film from plating
(1) Do Not Blast with Water (A) Blasting
(2) Never Wash from Too Close (B) Wide Spray
(C) Less Than 2.0 m (80 in.)
(D) Over 2.0 m (80 in.)
RY9212001GEG0038US0
G-14 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
6. TYPES OF OIL
[1] TABLE OF OIL AND FLUID CAPACITIES
Item KX057-4 U55-4 Notes
Engine oil (when replacing filter) 9.0 L (2.38 U.S. gal.) API class CJ-4
Radiator coolant (not including Canopy spec. 6.7 L (1.8 U.S. gal.)
coolant in reserve tank) Cabin spec. 7.0 L (1.85 U.S. gal.) KUBOTA LLC-N-50F 50%
Reserve tank coolant 1.1 L (0.29 U.S. gal.)
Total amount of • ISO 46 (In summer or with high
79 L (20.87 U.S. gal.)
oil ambient temperatures.)
Hydraulic oil • ISO 32 (In summer or with low
In tank
45 L (11.89 U.S. gal.) ambient temperatures.)
(gauge centre)
• Diesel Fuel No.2-DS15
75 L 68 L
Fuel tank capacity when full • Diesel Fuel No.1-DS15
(20 U.S. gal.) (18 U.S. gal.)
[Fuel under -5 °C (23 °F)]
Wheel motor 0.9 L (0.24 U.S. gal.) SAE90 (AP1, GL-4, GL-5)
Track rollers 80 ml (4.88 cu. in.)
Engine oil SAE #30CD
Front idler 50 ml (3.05 cu. in.)
Engine oil SAE #30CD *1
Carrier roller (Top track roller) 50 ml (3.05 cu. in.) Grease
EPNOC Grease AP2 *2
*1: KX057-4; To #28737, U55-4; To #26721
*2: KX057-4; From #28738, U55-4; From #26722
RY9212166GEG0010US0
[2] CHECKING AND FILLING HYDRAULIC OIL
Stop vehicle body on horizontal ground, extend cylinder rods to
near central position, and place bucket and blade on the ground.
Check that the hydraulic oil is in the centre of level gauge (2)
when at room temperature (10 to 30°C (50 to 86°F)).
The level is normal, if the oil is in the range (a) at or above the
centre of the level gauge.
If the oil level is lower, refill via the filler port (1).
(1) Filler Port (a) Normal Range of Hydraulic Oil
(2) Oil Level Gauge
RY9212166GEG0003US0
G-15 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
7. TIGHTENING TORQUES
[1] GENERAL USE SCREWS, BOLTS AND NUTS
Screws, bolts and nuts whose tightening torques are not specified in this Workshop Manual should be
tightened according to the table below.
Indication on top of bolt No-grade or 4T 7T 9T
Indication on top of nut No-grade or 4T
6T
Material of opponent part Ordinariness Aluminum Steel Aluminum Steel
Unit N·m kgf·m lbf·ft N·m kgf·m lbf·ft N·m kgf·m lbf·ft N·m kgf·m lbf·ft N·m kgf·m lbf·ft
7.9 0.8 5.8 7.9 0.8 5.8 9.81 1.0 7.24 7.9 0.8 5.8 12.3 1.25 9.05
M6 to to to to to to to to to to to to to to to
9.3 0.95 6.8 8.8 0.9 6.5 11.2 1.15 8.31 8.8 0.9 6.5 14.2 1.45 10.4
18 1.8 13 17 1.7 13 24 2.4 18 18 1.8 13 30 3.0 22
M8 to to to to to to to to to to to to to to to
20 2.1 15 19 2.0 14 27 2.8 20 20 2.1 15 34 3.5 25
40 4.0 29 32 3.2 24 48 4.9 36 40 4.0 29 61 6.2 45
M10 to to to to to to to to to to to to to to to
45 4.6 33 34 3.5 25 55 5.7 41 44 4.5 32 70 7.2 52
63 6.4 47 78 7.9 58 63 6.4 47 103 10.5 76
M12 to to to – – – to to to to to to to to to
72 7.4 53 90 9.2 66 72 7.4 53 117 12 86.7
108 11 79.6 124 12.6 91.2 167 17 123
M14 to to to – – – to to to – – – to to to
125 12.8 92.5 147 15 108 196 20 144
167 17 123 197 20 145 260 26.5 192
M16 to to to – – – to to to – – – to to to
191 19.5 141 225 23 166 304 31 224
246 25 181 275 28 203 344 35 254
M18 to to to – – – to to to – – – to to to
284 29 209 318 32.5 235 402 41 296
334 34 246 368 37.5 272 491 50 362
M20 to to to – – – to to to – – – to to to
392 40 289 431 44 318 568 58 419
RY9212032GEG0001US0
[2] STUD BOLTS
Material of opponent part Steel Aluminum
Unit N·m kgf·m lbf·ft N·m kgf·m lbf·ft
12 1.2 8.7 8.9 0.90 6.5
M8 to to to to to to
15 1.6 11 11 1.2 8.6
25 2.5 18 20 2.0 15
M10 to to to to to to
31 3.2 23 25 2.6 18
30 3.0 22
M12 to to to 31 3.2 23
49 5.0 36
62 6.3 46
M14 to to to – – –
73 7.5 54
98.1 10.0 72.4
M16 to to to – – –
112 11.5 83.1
172 17.5 127
M18 to to to – – –
201 20.5 148
RY9212032GEG0002US0
G-16 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
[3] TORQUE FOR HYDRAULIC HOSE FITTINGS
(1) Torque for Hydraulic Hose Fittings
Union Nuts
7.8 to 11.8 N·m
1/8 0.8 to 1.2 kgf·m
5.7 to 8.7 lbf·ft
24.5 to 29.2 N·m
1/4 2.5 to 3.0 kgf·m
18.1 to 21.7 lbf·ft
37.2 to 42.1 N·m
3/8 3.8 to 4.3 kgf·m
27.5 to 31.1 lbf·ft
58.8 to 63.7 N·m
Tightening torque 1/2 6.0 to 6.5 kgf·m
43.4 to 47.0 lbf·ft
117.6 to 127.4 N·m
3/4 12.0 to 13.0 kgf·m
86.8 to 94.0 lbf·ft
181.3 to 191.1 N·m
1 18.5 to 19.5 kgf·m
133.8 to 141.0 lbf·ft
210.7 to 220.5 N·m
1-1/4 21.5 to 22.5 kgf·m
162.7 to 168.0 lbf·ft
(1) Union Nuts
RY9212001GEG0041US0
Tapered Nuts
19.6 to 29.4 N·m
1/8 2.0 to 3.0 kgf·m
14.5 to 21.7 lbf·ft
36.6 to 44.1 N·m
1/4 3.7 to 4.5 kgf·m
26.8 to 32.5 lbf·ft
68.6 to 73.5 N·m
Tightening torque 3/8 7.0 to 7.5 kgf·m
50.6 to 54.2 lbf·ft
83.4 to 88.3 N·m
1/2 8.5 to 9.0 kgf·m
61.5 to 65.1 lbf·ft
166.6 to 181.3 N·m
3/4 17 to 18.5 kgf·m
123 to 133.8 lbf·ft
(1) Taper
RY9212001GEG0042US0
G-17 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
(2) Torques of Lock-Nuts for Elbows with Male Seats and Adaptors with
O-Rings (Straight Threads)
15.0 to 16.5 N·m
1/8 1.5 to 1.7 kgf·m
11.1 to 12.2 lbf·ft
24.5 to 29.4 N·m
1/4 2.5 to 3.0 kgf·m
18.1 to 21.7 lbf·ft
49.0 to 53.9 N·m
3/8 5.0 to 5.5 kgf·m
36.1 to 39.8 lbf·ft
Tightening torque
58.8 to 63.7 N·m
1/2 6.0 to 6.5 kgf·m
43.4 to 47.0 lbf·ft
117.6 to 127.4 N·m
3/4, 1 12.0 to 13.0 kgf·m
86.8 to 94.0 lbf·ft
220.5 to 230.3 N·m
1-1/4 22.5 to 23.5 kgf·m
162.8 to 170.0 lbf·ft
(1) Lock-Nut (3) Seal (O-Ring)
(2) Washer
RY9212001GEG0043US0
(3) Torque for Tapering Adaptors
19.6 to 29.4 N·m
1/8 2.0 to 3.0 kgf·m
14.5 to 21.7 lbf·ft
36.6 to 44.1 N·m
1/4 3.7 to 4.5 kgf·m
26.8 to 32.5 lbf·ft
68.6 to 73.5 N·m
Tightening torque 3/8 7.0 to 7.5 kgf·m
50.6 to 54.2 lbf·ft
83.4 to 88.3 N·m
1/2 8.5 to 9.0 kgf·m
61.5 to 65.1 lbf·ft
166.6 to 181.3 N·m
3/4 17 to 18.5 kgf·m
123 to 133.8 lbf·ft
(1) Taper
RY9212001GEG0044US0
G-18 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
[4] HOSE CLAMP SCREW TORQUE
Type 1
2.5 to 3.4 N·m
10- 14 6C040-58721 25 to 35 kgf·cm
1.8 to 2.5 lbf·ft
2.5 to 3.4 N·m
12- 16 09318-89016 25 to 35 kgf·cm
1.8 to 2.5 lbf·ft
2.5 to 3.4 N·m
19- 25 09318-89024 25 to 35 kgf·cm
1.8 to 2.5 lbf·ft
2.5 to 3.4 N·m
31- 40 09318-89039 25 to 35 kgf·cm
1.8 to 2.5 lbf·ft
Tightening torque
2.5 to 3.4 N·m
36- 46 09318-89045 25 to 35 kgf·cm
1.8 to 2.5 lbf·ft
3.9 to 4.9 N·m
44- 53 09318-89052 40 to 50 kgf·cm
2.9 to 3.6 lbf·ft
3.9 to 4.9 N·m
51- 59 09318-89058 40 to 50 kgf·cm
2.9 to 3.6 lbf·ft
2.5 to 3.4 N·m
86- 96 RD809-42241 25 to 35 kgf·cm
1.8 to 2.5 lbf·ft
RY9212001GEG0045US0
G-19 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
Type 2
2.5 to 3.4 N·m
13- 20 RB101-63631 25 to 35 kgf·cm
1.8 to 2.5 lbf·ft
4.9 to 5.9 N·m
15- 25 RC101-64581 50 to 60 kgf·cm
3.6 to 4.3 lbf·ft
4.9 to 5.9 N·m
19- 28 R1401-63211 50 to 60 kgf·cm
3.6 to 4.3 lbf·ft
4.9 to 5.9 N·m
22- 32 R1401-63151 50 to 60 kgf·cm
3.6 to 4.3 lbf·ft
4.9 to 5.9 N·m
26- 38 68311-72821 50 to 60 kgf·cm
3.6 to 4.3 lbf·ft
4.9 to 5.9 N·m
32- 44 RD411-63821 50 to 60 kgf·cm
3.6 to 4.3 lbf·ft
Tightening torque
4.9 to 5.9 N·m
44- 56 35820-15181 50 to 60 kgf·cm
3.6 to 4.3 lbf·ft
4.9 to 5.9 N·m
50- 65 RC401-63191 50 to 60 kgf·cm
3.6 to 4.3 lbf·ft
4.9 to 5.9 N·m
58- 75 36919-04591 50 to 60 kgf·cm
3.6 to 4.3 lbf·ft
4.9 to 5.9 N·m
60- 80 RD809-63101 50 to 60 kgf·cm
3.6 to 4.3 lbf·ft
4.9 to 5.9 N·m
68- 85 RD809-63061 50 to 60 kgf·cm
3.6 to 4.3 lbf·ft
4.9 to 5.9 N·m
77- 95 69284-63171 50 to 60 kgf·cm
3.6 to 4.3 lbf·ft
RY9212001GEG0046US0
G-20 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
8. MAINTENANCE
Hour meter indicator
No. Check points Measures Interval
50 100 150 200 250 300 350 400 450 500
check Daily check
1 Coolant every
change
2 years
2 Fuel check Daily check
check Daily check
3 Engine oil every
change
500 hrs
check Daily check
4 Hydraulic oil every
change *1
1000 hrs
Bucket and bucket
link pin / Dozer
angle pin and – Daily check
Grease front angle cylinder
5
attachments boss
Boom swing
– Daily check
fulcrum
Others – Daily check
6 Radiator and oil cooler check Daily check
7 Washer liquid check Daily check
8 Engine and electrical wiring check Daily check
every
9 Fuel tank, Water separator drain
50 hrs
every
10 Battery condition check
50 hrs
every
11 Greasing swing bearing teeth –
50 hrs
check Daily check
12 V-belt tension every
adjust
200 hrs
every
check
200 hrs
13 Radiator hoses and clamps
every
replace
2 years
every
clean *2
200 hrs
Outer element
Air filter every
14 replace *2 @
element 1000 hrs
every
Inner element replace *2
1000 hrs
every
15 Greasing swing ball bearing –
200 hrs
every
16 Evacuator valve clean
200 hrs
every
17 DPF muffler check
200 hrs
every
check
200 hrs
18 Fuel line and Intake air line @
every
replace *3
2 years
every
19 Water separator filter element replace
250 hrs
every
20 Fuel filter cartridge replace @
500 hrs
every
21 Engine oil filter replace
500 hrs
every
22 Drive unit oil change
500 hrs
every
23 Breather filter replace
500 hrs
G-21 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
Hour meter indicator
No. Check points Measures Interval
50 100 150 200 250 300 350 400 450 500
every
24 Hydraulic return filter element replace
1000 hrs
every
25 Hydraulic suction filter element replace
1000 hrs
every
26 Filter in the pilot hydraulic system replace
1000 hrs
every
27 Injector tip check *4 @
1500 hrs
every
28 Oil separator element replace @
1500 hrs
every
29 EGR cooler check *4 @
1500 hrs
every
30 Alternator and starter motor check
2000 hrs
every
31 EGR system check *4 @
3000 hrs
every
32 DPF clean *4 @
3000 hrs
Exhaust manifold (crack, gas, every
33 check *4
leakage and mounting screw) 1 years
every
34 Intake air line for air leaks check *4
1 years
Boost sensor and AFS (Air flow every
35 check *4
sensor) 1 years
every
36 Condition of DPF muffler check *4
1 years
DPF differential pressure sensor every
37 check *4
and piping for gas leak 1 years
DPF exhaust gas temperature every
38 check *4
sensor 1 years
every
39 EGR and piping for gas leak check *4
1 years
every
40 Radiator system rinse *4
2 years
Closed breather related rubber every
41 replace *4
piping 2 years
DPF differential pressure sensor every
42 replace *4
rubber piping (Front and back) 2 years
Suction pipe downstream the every
43 replace *4
AFS (Air flow sensor) 2 years
Boost sensor pressure rubber every
44 replace *4
piping 2 years
every
45 EGR cooler hose replace *4
2 years
∗ 550 thru 3000 continued to the following table.
• : KTC, KCL only
G-22 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
Hour meter indicator
No. Check points Measures Interval
550 600 650 700 750 800 1000 1500 3000
check Daily check
1 Coolant every
change
2 years
2 Fuel check Daily check
check Daily check
3 Engine oil every
change
500 hrs
check Daily check
4 Hydraulic oil every
change *1
1000 hrs
Bucket and bucket
link pin / Dozer
angle pin and – Daily check
Grease front angle cylinder
5
attachments boss
Boom swing
– Daily check
fulcrum
Others – Daily check
6 Radiator and oil cooler check Daily check
7 Washer liquid check Daily check
8 Engine and electrical wiring check Daily check
every
9 Fuel tank, Water separator drain
50 hrs
every
10 Battery condition check
50 hrs
every
11 Greasing swing bearing teeth –
50 hrs
check Daily check
12 V-belt tension every
adjust
200 hrs
every
check
200 hrs
13 Radiator hoses and clamps
every
replace
2 years
every
clean *2
200 hrs
Outer element
Air filter every
14 replace *2 @
element 1000 hrs
every
Inner element replace *2
1000 hrs
every
15 Greasing swing ball bearing –
200 hrs
every
16 Evacuator valve clean
200 hrs
every
17 DPF muffler check
200 hrs
every
check
200 hrs
18 Fuel line and Intake air line @
every
replace *3
2 years
every
19 Water separator filter element replace
250 hrs
every
20 Fuel filter cartridge replace @
500 hrs
every
21 Engine oil filter replace
500 hrs
every
22 Drive unit oil change
500 hrs
every
23 Breather filter replace
500 hrs
every
24 Hydraulic return filter element replace
1000 hrs
G-23 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
Hour meter indicator
No. Check points Measures Interval
550 600 650 700 750 800 1000 1500 3000
every
25 Hydraulic suction filter element replace
1000 hrs
every
26 Filter in the pilot hydraulic system replace
1000 hrs
every
27 Injector tip check *4 @
1500 hrs
every
28 Oil separator element replace @
1500 hrs
every
29 EGR cooler check *4 @
1500 hrs
every
30 Alternator and starter motor check
2000 hrs
every
31 EGR system check *4 @
3000 hrs
every
32 DPF clean *4 @
3000 hrs
Exhaust manifold (crack, gas, every
33 check *4
leakage and mounting screw) 1 years
every
34 Intake air line for air leaks check *4
1 years
Boost sensor and AFS (Air flow every
35 check *4
sensor) 1 years
every
36 Condition of DPF muffler check *4
1 years
DPF differential pressure sensor every
37 check *4
and piping for gas leak 1 years
DPF exhaust gas temperature every
38 check *4
sensor 1 years
every
39 EGR and piping for gas leak check *4
1 years
every
40 Radiator system rinse *4
2 years
Closed breather related rubber every
41 replace *4
piping 2 years
DPF differential pressure sensor every
42 replace *4
rubber piping (Front and back) 2 years
Suction pipe downstream the every
43 replace *4
AFS (Air flow sensor) 2 years
Boost sensor pressure rubber every
44 replace *4
piping 2 years
every
45 EGR cooler hose replace *4
2 years
• : KTC, KCL only
G-24 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM GENERAL
Air-conditioner
Hour meter indicator
No. Check points Measures Interval
50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 1000
every
clean *2
200 hrs
1 Air filter
every
replace *2
1000 hrs
every
2 Air conditioner condenser clean
200 hrs
every
check
1 year
3 Air conditioner pipes and hoses
every
replace
2 years
service as
4 Refrigerant (gas) check
required
IMPORTANT
• : First operation
• *1 : When using a hydraulic hammer, change hydraulic oil and return filter according to the table on
"Hydraulic Oil" Change (Including Exchange of the Suction Filter in the Hydraulic Tank) under "EVERY
1000 SERCVICE HOURS" in the chapter "REGULAR CHECKS AND MAINTENANCE WORK".
• *2 : Clean and replace the air filter more frequently if used under dusty conditions. When the filter is very
dirty from dusty conditions, replace the filter.
• *3 : Replace only if necessary.
• *4 : Consult your local KUBOTA dealer for this service.
• The items listed above (@ mark) are registered as emission related critical parts by KUBOTA in the
U.S.EPA non-road emission regulation. As the engine owner, you are responsible for the performance of
the required maintenance on the engine according to the instruction. Please see the warranty Statement
in detail.
RY9212166GEG0004US0
NOTE
Engine Oil:
• Oil used in the engine should have an American Petroleum Institute (API) service classification and
Proper SAE Engine Oil according to the ambient temperatures.
Above 25 °C (77 °F) SAE30 or SAE 10W-30, SAE 15W-40
0 °C to 25 °C (32 °F to 77 °F) SAE20 or SAE 10W-30, SAE 15W-40
Below 0 °C (32 °F) SAE10W or SAE 10W-30, SAE 15W-40
• Refer to the following table for the suitable API classification engine oil and the fuel.
Engine oil classification (API classification)
Fuel used
Oil class of engines except external DPF
Ultra Low Sulfur Fuel [< 0.0015 % (15 ppm)] CJ-4
Fuel:
• Use the ultra low sulfur diesel fuel only [below 0.0015 % (15 ppm)] for these engines.
• Cetane number of 45 minimum. Cetane number greater than 50 is preferred, especially for temperatures below
-20 °C (-4 °F) or elevations above 1500 m (5000 ft).
• Diesel fuels specified to EN 590 or ASTM D975 are recommended.
• No. 2-D is a distillate fuel of lower volatility for engines in industrial and heavy mobile service. (SAE J313 JUN87)
• Indicated capacities of water and oil are manufacture's estimate.
IMPORTANT
• If you use different fuel or engine oil, the cleaning interval of the DPF (3000 hours) can't be secured and
the DPF will be clogged for a shorter time than expected.
RY9212134GEG0062US0
G-25 KiSC issued 04, 2021 A
1 MACHINE BODY
KiSC issued 04, 2021 A
SERVICING
CONTENTS
1. FRONT OPERATING MACHINE.................................................................................................1-S2
[1] AUX1 ARM LINES.................................................................................................................1-S2
[2] BUCKET INSTALLATION RELEVANT DIMENSIONS..........................................................1-S3
[3] FRONT PIN ...........................................................................................................................1-S4
[4] BLADE...................................................................................................................................1-S5
(1) Blade Dimension .............................................................................................................1-S5
(2) Angle Blade Components................................................................................................1-S6
2. SWIVEL FRAME..........................................................................................................................1-S7
[1] WEIGHT DIASSEMBLY / ASSEMBLY ..................................................................................1-S7
[2] CANOPY ...............................................................................................................................1-S9
[3] FUEL TANK.........................................................................................................................1-S10
[4] HYDRAULIC OIL TANK ......................................................................................................1-S16
(1) Hydraulic Oil Tank Components....................................................................................1-S16
(2) Hydraulic Oil Return Filter Replacement Procedure......................................................1-S17
(3) Filter (Suction) Replacement Procedure .......................................................................1-S18
(4) Filter (Breather) Replacement Procedure......................................................................1-S19
(5) Assembly of Anti Vibration Support for the Hydraulic Oil Tank .....................................1-S20
[5] ENGINE...............................................................................................................................1-S21
(1) Engine Diassembly / Assembly .....................................................................................1-S21
(2) Engine Mount Installation ..............................................................................................1-S24
(3) Arch, Air Cleaner ...........................................................................................................1-S25
(4) Radiator .........................................................................................................................1-S26
(5) Oil Cooler.......................................................................................................................1-S27
[6] DPF MUFFLER ...................................................................................................................1-S28
(1) DPF Muffler Diassembly / Assembly .............................................................................1-S28
(2) DPF Muffler Assembly...................................................................................................1-S30
(3) Assembling of DPF Exhaust Pipe and DPF Cover........................................................1-S31
[7] ASSEMBLING OF OPERATING LEVERS ..........................................................................1-S32
(1) Travel Lever...................................................................................................................1-S32
(2) Blade Lever ...................................................................................................................1-S33
3. TRACK FRAME .........................................................................................................................1-S34
[1] ASSEMBLING OF SWIVEL BEARING ...............................................................................1-S34
[2] TRACK ................................................................................................................................1-S36
(1) Assembly / Disassembly of Rubber Track.....................................................................1-S36
(2) Assembly / Disassembly of Iron Tracks.........................................................................1-S37
[3] RUBBER CRAWLER...........................................................................................................1-S40
[4] STEEL CRAWLER ..............................................................................................................1-S40
[5] FRONT IDLER.....................................................................................................................1-S41
(1) Assembly/Disassembly of Front Idler ............................................................................1-S41
(2) Front Idler Structural Components ................................................................................1-S41
[6] SPRING ASSY ....................................................................................................................1-S42
(1) Assembly/Disassembly of Spring Assy .........................................................................1-S42
[7] CYLINDER ASSEMBLY ......................................................................................................1-S43
(1) Assembly/Disassembly of Cylinder Assy.......................................................................1-S43
(2) Cylinder Assembly Structural Components ...................................................................1-S43
[8] TRACK ROLLER .................................................................................................................1-S45
(1) Assembly/Disassembly of Track Roller .........................................................................1-S45
(2) Track Roller Structural Components .............................................................................1-S46
[9] CARRIER ROLLER .............................................................................................................1-S47
KiSC issued 04, 2021 A
(1) Assembly/Disassembly of Carrier Roller .......................................................................1-S47
(2) Carrier Roller Structural Components............................................................................1-S48
[10]TRUCK ROLLER, IDLER AND SPROCKET DIMENSIONS ...............................................1-S49
KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Machine Structure
1. Front equipment 2. Upper swivel unit 3. Lower travel unit
(1) Bucket (5) Weight (14) Swivel bearing
(2) Arm (6) Fuel tank (15) Track
(3) Boom (7) Hydraulic oil tank (16) Front idler
(4) Blade (8) Return filter (17) Spring assembly
(9) Suction filter (18) Cylinder assembly
(10) Engine (19) Track rollers
(11) Travel lever (20) Carrier rollers
(12) Blade lever
(13) Steering pilot lever
RY9212166MBS0001US0
1-S1 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
1. FRONT OPERATING MACHINE
[1] AUX1 ARM LINES
(1) Selector Valve
(2) O-Ring
(3) Hydraulic Pipe
(4) Joint
(5) Pipe Joint
(6) Plug
(7) Plug (G/2)
(a) KX057-4: 400 to 403 mm
(15.7 to 15.9 in.) U55-4: 289
to 292 mm (11.4 to 11.5 in.)
(b) 4 mm (0.2 in.)
(c) Rotates Plate to Switch Oil
Flow.
[Hydraulic pipe assembly sequence]
• (A) Fit the O-ring onto the pipe.
• (B) Fit the pipe onto the selector valve and tighten.
58.8 to 63.7 N·m
Tightening torque Hydraulic pipe 6.0 to 6.5 kgf·m
43.4 to 47.0 lbf·ft
• (C) Raise the lock nut on the pipe up to the base of the adapter.
• (D) Screw on by hand until the joint meets the washer.
• (E) Move the joint back until the installation surface of the selector valve and the joint is horizontal. (Part b)
• (F) Tighten the lock nut.
58.8 to 63.7 N·m
Tightening torque Lock nut 6.0 to 6.5 kgf·m
43.4 to 47.0 lbf·ft
• (G) Use the bolts to install on the arm.
48.1 to 55.9 N·m
Tightening torque Bolt 4.9 to 5.7 kgf·m
35.5 to 41.2 lbf·ft
• (H) Set oil passage to thumb bracket side.
RY9212166MBS0049US0
1-S2 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[2] BUCKET INSTALLATION RELEVANT DIMENSIONS
(A) Arm Tip (B) Bucket, Link 1
KX057 KX057 KX057 KX057
No. KX057-4 U55-4 No. U55-4 No. U55-4 No. U55-4 No. U55-4
-4 -4 -4 -4
200 mm 335 mm 10 mm 45 mm 61 mm
(1) (5) (9) (13) (17)
7.87 in. 13.19 in. 0.39 in. 1.77 in. 2.40 in.
1620 mm 1370 mm 1360 mm 145 mm 45 mm 45 mm
(2) (6) (10) (14) (18)
63.78 in. 53.94 in. 53.54 in. 5.71 in. 1.77 in. 1.77 in.
353 mm 315 mm 133 mm 145 mm 45 mm
(3) (7) (11) (15) (19)
13.90 in. 12.40 in. 5.24 in. 5.71 in. 1.77 in.
193 mm 335 mm 145 mm 145 mm
(4) (8) (12) (16)
7.60 in. 13.19 in. 5.71 in. 5.71 in.
RY9212166MBS0002US0
1-S3 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[3] FRONT PIN
Dimension
Pin diameter x 92 x 176 mm
(1)
length 3.62 x 6.93 in.
Pin diameter x 92 x 150 mm
(2)
length 3.62 x 5.91 in.
Pin diameter x 45 x 158 mm
(3)
length 1.77 x 6.22 in.
Pin diameter x 45 x 131 mm
(4)
length 1.77 x 5.16 in.
Pin diameter x 55 x 347 mm
(5)
length 2.17 x 13.66 in.
Pin diameter x 55 x 165 mm
(6)
length 2.17 x 6.50 in.
Pin diameter x 55 x 196 mm
(7)
length 2.17 x 7.72 in.
Pin diameter x 55 x 235 mm
(8)
length 2.17 x 9.25 in.
Pin diameter x 50 x 196 mm
(9)
length 1.97 x 7.72 in.
Pin diameter x 50 x 152 mm
(10)
length 1.97 x 5.98 in.
Pin diameter x 45 x 257 mm
(11)
length 1.77 x 10.12 in.
Pin diameter x 45 x 257 mm
(12)
length 1.77 x 10.12 in.
Pin diameter x 45 x 152 mm
(13)
length 1.17 x 5.98 in.
Pin diameter x 45 x 204 mm
(14)
length 1.77 x 8.03 in.
Pin diameter x 45 x 204 mm
(15)
length 1.77 x 8.03 in.
Pin diameter x 45 x 142 mm
(16)
length 1.77 x 5.59 in.
Pin diameter x 55 x 154 mm
(17)
length 2.17 x 6.06 in.
Pin diameter x 70 x 240 mm
(18)
length 2.8 x 9.5 in.
Pin diameter x 40 x 140 mm
(19)
length 1.6 x 5.5 in.
NOTE
• Service limit of pin and bushing is 1.0 mm (0.04 in.) less and
more than original diameter respectively.
(a) Pin Diameter (b) Pin Length
RY9212166MBS0086US0
1-S4 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[4] BLADE
(1) Blade Dimension
Dimension (STD version)
(a) Pin diameter x length 55 x 65 mm ( 2.2 x 2.6 in.)
(b) Pin diameter x length 55 x 25 mm ( 2.2 x 1 in.)
(c) Blade width 1960 mm (77.2 in.)
(d) Blade height 408 mm (16.1 in.)
(e) Blade length 1365 mm (53.7 in.)
Blade tip plate height
(f) 65 x t12 mm (2.6 x t0.5 in.)
x thickness
Length between
(g) 599 mm (23.6 in.)
blade arms
RY9212050MBS0014US0
Dimension (Angle blade version)
(a) Pin diameter x length 55 x 65 mm ( 2.2 x 2.6 in.)
(b) Pin diameter x length 55 x 25 mm ( 2.2 x 1 in.)
(c) Pin diameter 82 mm ( 3.2 in.)
(d) Blade width 1960 mm (77.2 in.)
(e) Blade height 425 mm (16.7 in.)
(f) Blade length 1526 mm (60.1 in.)
(g) Blade tip plate height x thickness 100 x t12 mm (3.7 x t0.5 in.)
(h) Length between blade arms 599 mm (23.6 in.)
(i) Cutting blade 57 mm (2.2 in.)
(j) Cutting blade 173 mm (6.8 in.)
(k) Cutting blade 346 mm (13.6 in.)
(l) Cutting blade 979 mm (38.5 in.)
RY9212050MBS0015US0
1-S5 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(2) Angle Blade Components
(1) Kit Blade (11) Nipple, Grease (21) Nipple, Grease (31) Cover, Angle
(2) Label (12) Bush (22) Bolt (M12x20) (32) Bolt (M10x20)
(3) Label (13) Seal, Dust (23) Washer, Plain (33) Pin
(4) Blade, Cutting (14) Pin (24) Bracket (34) Bolt (M12x80)
(5) Bolt (15) Nipple, Grease (25) Bolt (M10x20) (35) Nut, Lock
(6) Washer, Spring (16) Bolt (M12x20) (26) Cover, Angle Cylinder (36) Pin
(7) Nut (M14) (17) Washer, Plain (27) Cap, Cylinder Cover (37) Bolt (M12x85)
(8) Assy Frame (18) Collar, Thrust (28) Collar (38) Nut, Lock
(9) Bush (19) Collar, Thrust (29) Bolt (M10x20)
(10) Collar (20) Pin (30) Washer, Plain
RY9212050MBS0016US0
1-S6 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
2. SWIVEL FRAME
[1] WEIGHT DIASSEMBLY / ASSEMBLY
Removing the right bonnet
1. Open the right bonnet, remove the two snap pins, and separate
the gas damper from the bonnet.
2. Slide the right bonnet to the front of the body and remove it.
CAUTION
• The task of removing the right bonnet must be carried out
by at least two persons.
• Weight of right bonnet : 27 kg (60 lbs)
(1) Snap Pin - Flat Metal Washer (3) Gas Damper
(2) Snap Pin - Flat Metal Washer (4) Right Bonnet
RY9212166MBS0003US0
Removing the rear bonnet
1. Open the rear bonnet, remove the fixing bolts and detach the
rear bonnet.
(1) Rear Bonnet (2) Bolt (M10 X 25)
RY9212166MBS0004US0
Removing the left bonnet
1. Remove the left bonnet mounting bolts and the fuel tank cap,
and then remove the left bonnet.
(1) Left Bonnet (3) Bolt (M10 X 25)
(2) Bolt (M10 X 35)
RY9212166MBS0005US0
Removing the bracket
1. Remove the mounting bolts on the rear bonnet fixing bracket
and then remove the bracket.
(1) Bracket
RY9212166MBS0050US0
1-S7 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Removing the DPF muffler pipe
1. Remove the DPF muffler pipe mounting bolts and then remove
the DPF muffler pipe.
(1) DPF Muffler Pipe (3) Bolt (M10 X 20)
RY9212166MBS0051US0
Removing the weight
1. Attach two eyebolts to the weight, connect a nylon sling to these
and support the weight using a crane.
2. Remove the three mounting bolts of the weight, lift slightly with
the crane, slide the weight to the rear, lift the weight and remove
it from the frame.
367.7 to 431.5 N·m
Tightening torque Bolt (3) 37.5 to 44.0 kgf·m
271.2 to 318.3 lbf·ft
Thread locking compound (Loctite® 271)
680 kg
KX057-4
1500 lbs
Mass of weight
700 kg
U55-4
1540 lbs
CAUTION
• When assembling the weight, align the protruding part B of
the weight with the indent part A in the frame and line up
the mounting holes.
(1) Weight A : Indent Part in Frame
(2) Eyebolt (M24 X P3) B : Protruding Part of Weight
(3) Bolt (M20 X 90)
(4) Nylon Sling
RY9212166MBS0006US0
1-S8 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[2] CANOPY
Assembling the canopy
(1) Canopy, Rops
(2) Plug
(3) Bolt (M16 x 1.5)
(4) Washer
(5) Rail, Hand
(6) Bolt
RY9212050MBS0018US0
196.1 to 225.6 N·m
Tightening torque Bolt (3) 20.0 to 23.0 kgf·m
144.6 to 166.4 lbf·ft
(3) Bolt (M16x1.5)
RY9212050MBS0019US0
1-S9 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[3] FUEL TANK
Assembling the fuel tank (KX057-4)
(1) Fuel Tank Assembly (5) Plate, Assy (7) Flat Metal Washer (9) Bolt (M10 x 25)
(2) Band, Assy (Fuel Tank) (1, Fuel Tank Support) (8) Plate, Assy (10) Flat Metal Washer
(3) Lock Nut (6) Bolt (M10 x 20) (2, Fuel Tank Support)
(4) Flat Metal Washer
NOTE
• (a) : Tolerance from the frame (swivel) partition plate to band screw part : 20 to 25 mm (0.79 to 0.98 in.)
RY9212166MBS0007US0
Assembly of fuel hose (KX057-4)
(1) Fuel Tank Assembly (2) Bolt (M10 X 25)
NOTE
• (a) : Cock closed position
• (b) : Make sure the hose does not get caught between the frame (swivel) and the fuel tank.
• (c) : Arrange the hose between the fuel tank and the W separator, on the underside of the machine.
• (d) : Check that the hose is not kinked after assembly.
• (e) : Must not interfere with the corner.
RY9212166MBS0008US0
1-S10 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Assembling the fuel tank (U55-4)
(1) Fuel Tank Assembly (5) Plate, Assy (7) Flat Metal Washer (9) Bolt (M10 x 25)
(2) Band, Assy (Fuel Tank) (1, Fuel Tank Support) (8) Plate, Assy (10) Flat Metal Washer
(3) Lock Nut (6) Bolt (M10 x 20) (2, Fuel Tank Support)
(4) Flat Metal Washer
NOTE
• (a) : Tolerance from the frame (swivel) partition plate to band screw part : 20 to 25 mm (0.79 to 0.98 in.)
RY9212166MBS0040US0
Assembling the fuel hose (U55-4)
(1) Fuel Tank Assembly (2) Bolt (M10 x 25)
NOTE
• (a) : Cock closed position
• (b) : Be careful to make sure the hose does not get caught between the frame (swivel) and the fuel tank.
RY9212166MBS0041US0
1-S11 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Others
SWIVEL FRAME
(1) Drain Cock (4) Fuel Pump (6) Engine (8) Check Valve
(2) Fuel Tank (5) Fuel Filter (7) Fuel Cooler (9) Joint
(3) Sedimenter (Separator)
RY9212166MBS0089US0
List of fuel hoses
KX057-4 (To #27469)
Fuel tube Protection tube Hose band
Part Length Part Length IN / Out side
A RD358-51331 800 mm (31.5 in.) RD358-51341 680 mm (26.8 in.) 09318-88130
B 09664-82100 2100 mm (82.7 in.) RC301-51151 2000 mm (78.7 in.) 14911-42751
C 09664-80550 550 mm (21.7 in.) RD568-51341 450 mm (17.7 in.) 14911-42751
D 09664-81300 1300 mm (51.2 in.) RD568-51491 1200 mm (47.2 in.) 14911-42751
E 09664-81550 1500 mm (61.0 in.) RD568-51461 1450 mm (57.1 in.) 14911-42751
F 09664-81200 1200 mm (47.2 in.) RD568-51351 1100 mm (43.3 in.) 14971-42751
G 09664-80040 40 mm (1.6 in.) – – 14971-42751
H 09664-82300 2300 mm (90.6 in.) RD568-51381 2200 mm (86.6 in.) 14911-42751
I RB238-51361 – – – 14911-42751
J 09664-40950 950 mm (37.4 in.) RD568-51321 850 mm (35.5 in.) 09318-88080
K 09664-40040 40 mm (1.6 in.) – – 09318-88080
L RB238-51361 – – – 14911-42751
M 09661-60400 400 mm (15.7 in.) – – –
N 09661-50480 480 mm (18.9 in.) – – 09318-88085
U55-4 (To #26075)
Fuel tube Protection tube Hose band
Part Length Part Length IN / Out side
A RD451-5132 730 mm (28.7 in.) RD451-51341 610 mm (24 in.) 09318-88130
B 09664-82100 2100 mm (82.7 in.) RC301-51151 2000 mm (78.7 in.) 09318-88130 / 14911-42751
C 09664-80550 550 mm (21.7 in.) RD568-51341 450 mm (17.7 in.) 14911-42751
D 09664-81300 1300 mm (51.2 in.) RD568-51491 1200 mm (47.2 in.) 14911-42751
E 09664-81550 1550 mm (61.0 in.) RD568-51461 1450 mm (57.1 in.) 14911-42751
F 09664-81200 1200 mm (47.2 in.) RD568-51351 1100 mm (43.3 in.) 14971-42751
G 09664-80040 40 mm (1.6 in.) – – 14971-42751
H 09664-82300 2300 mm (90.6 in.) RD568-51381 2200 mm (86.6 in.) 14911-42751
I RB238-51361 – – – 14911-42751
J 09664-40950 950 mm (37.4 in.) RD568-51321 850 mm (33.5 in.) 09318-88080
K 09664-40040 40 mm (1.6 in.) – – 09318-88080
L RB238-51361 – – – 14911-42751
M 09661-60400 400 mm (15.7 in.) – – –
N 09661-50480 480 mm (18.9 in.) – – 09318-88085
1-S12 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
RY9212166MBS0010US0
KTC, KCL
(1) Drain Cock (4) Fuel Pump (6) Engine (8) Check Valve
(2) Fuel Tank (5) Fuel Filter (7) Fuel Cooler (9) Joint
(3) Sedimenter (Separator)
RY9212166MBS0087US0
List of fuel hoses
KX057-4 (From #27470)
Fuel tube Protection tube Hose band
Part Length Part Length IN / Out side
A RD358-51331 800 mm (31.5 in.) RD358-51341 680 mm (26.8 in.) 09318-88130
B 09664-82100 2100 mm (82.7 in.) RC301-51151 2000 mm (78.7 in.) 14911-42751
C 09664-80550 550 mm (21.7 in.) RD568-51341 450 mm (17.7 in.) 14911-42751
D 09664-81300 1300 mm (51.2 in.) RD568-51491 1200 mm (47.2 in.) 14911-42751
E 09664-81550 1500 mm (61.0 in.) RD568-51461 1450 mm (57.1 in.) 14911-42751
F 09664-81200 1200 mm (47.2 in.) RD568-51351 1100 mm (43.3 in.) 14971-42751
G 09664-80040 40 mm (1.6 in.) – – 14971-42751
H 09664-82300 2300 mm (90.6 in.) RD568-51381 2200 mm (86.6 in.) 14911-42751
I RB238-51361 – – – 14911-42751
J 09664-40950 950 mm (37.4 in.) RD568-51321 850 mm (35.5 in.) 09318-88080
K 09664-40040 40 mm (1.6 in.) – – 09318-88080
L RB238-51361 – – – 14911-42751
M 09661-60400 400 mm (15.7 in.) – – –
N 09661-50480 480 mm (18.9 in.) – – 09318-88085
P 09664-80050 50 mm (1.97 in.) – – –
35 x 45 mm
Q RD158-51651 – – 14911-42751
(1.38 X 1.77 in.)
R 09664-80775 775 mm (30.5 in.) RD568-51271 675 mm (26.6 in.) 14911-42751
35 x 60 mm
S RB238-51362 – – 14911-42751
(1.38 X 2.36 in.)
T 09664-80150 150 mm (5.91 in.) RD568-51291 50 mm (1.97 in.) 14911-42751
35 x 60 mm
U RB238-51362 – – 14911-42751
(1.38 X 2.36 in.)
V 09664-80130 130 mm (5.12 in.) – – 14911-42751
1-S13 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
U55-4 (From #26076)
Fuel tube Protection tube Hose band
Part Length Part Length IN / Out side
A RD451-5132 730 mm (28.7 in.) RD451-51341 610 mm (24 in.) 09318-88130
B 09664-82100 2100 mm (82.7 in.) RC301-51151 2000 mm (78.7 in.) 09318-88130 / 14911-42751
C 09664-80550 550 mm (21.7 in.) RD568-51341 450 mm (17.7 in.) 14911-42751
D 09664-81300 1300 mm (51.2 in.) RD568-51491 1200 mm (47.2 in.) 14911-42751
E 09664-81550 1550 mm (61.0 in.) RD568-51461 1450 mm (57.1 in.) 14911-42751
F 09664-81200 1200 mm (47.2 in.) RD568-51351 1100 mm (43.3 in.) 14971-42751
G 09664-80040 40 mm (1.6 in.) – – 14971-42751
H 09664-82300 2300 mm (90.6 in.) RD568-51381 2200 mm (86.6 in.) 14911-42751
I RB238-51361 – – – 14911-42751
J 09664-40950 950 mm (37.4 in.) RD568-51321 850 mm (33.5 in.) 09318-88080
K 09664-40040 40 mm (1.6 in.) – – 09318-88080
L RB238-51361 – – – 14911-42751
M 09661-60400 400 mm (15.7 in.) – – –
N 09661-50480 480 mm (18.9 in.) – – 09318-88085
P 09664-80050 50 mm (1.97 in.) – – –
35 x 45 mm
Q RD158-51651 – – 14911-42751
(1.38 X 1.77 in.)
R 09664-80775 775 mm (30.5 in.) RD568-51271 675 mm (26.6 in.) 14911-42751
35 x 60 mm
S RB238-51362 – – 14911-42751
(1.38 X 2.36 in.)
T 09664-80150 150 mm (5.91 in.) RD568-51291 50 mm (1.97 in.) 14911-42751
35 x 60 mm
U RB238-51362 – – 14911-42751
(1.38 X 2.36 in.)
V 09664-80130 130 mm (5.12 in.) – – 14911-42751
RY9212166MBS0088US0
1-S14 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Fuel hose clamp, guide position
(1) Guide (3) Clamp
(2) Clamp
RY9212166MBS0009US0
1-S15 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[4] HYDRAULIC OIL TANK
(1) Hydraulic Oil Tank Components
(1) Hydraulic Oil Tank (7) Plug (Fill) (13) Bolt (M10 × 16) (20) Sealing Washer
(2) Cover (Tank) (8) O-Ring (14) Plug (G1/4) (21) Flange Holder
(3) O-Ring (9) Bolt (M10 × 16) (15) O-Ring (22) Tube (Blazer)
(4) Filter (Return) (10) Filter, Assy (Suction) (16) Plug (23) Magnet Plug
(5) Stopper (Return Filter) (11) Pin (Suction Filter) (17) Sealing Washer (24) Sealing Washer
(6) Bolt (M8 × 16) (12) O-Ring (18) Filter (Blazer) (25) Bolt (M12 × 30)
(19) Metal Washer
77.5 to 90.2 N·m
Tightening torque Bolt (25) 7.9 to 9.2 kgf·m
57.2 to 66.5 lbf·ft
Apply thread locking compound (Loctite 271) to the bolt (25).
RY9212050MBS0030US0
1-S16 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(2) Hydraulic Oil Return Filter Replacement Procedure
Removing the cover (tank)
1. Loosen the hose clamp (3), remove the hose (return) (4), hose
(return, cooler) (5), from the cover (tank) (1) side.
2. Remove the cover (tank) (1) mounting bolt (2).
(1) Cover (Tank) (4) Hose (Return)
(2) Bolt (5) Hose (Return, Cooler)
(3) Hose Clamp
RY9212166MBS0077US0
3. Pull up the cover (tank) (1) and remove the filter (return) (6).
(1) Cover (Tank) (6) Filter (Return)
RY9212166MBS0078US0
4. Clamp in a vice, loosen the set bolt (7), and remove the stopper
(8).
(7) Set Bolt (8) Stopper
RY9212001MBS0054US0
5. Remove the filter (return) (9) using a wrench (1).
Wrench : 41 mm, 1.6 in. (two opposite faces)
68.6 to 78.4 N·m
Tightening torque Filter (return) (9) 7.0 to 8.0 kgf·m
50.6 to 57.8 lbf·ft
CAUTION
• When tightening the filter (return), tighten with the wrench
(1) on the nut (b) shown in the diagram to the left.
If the wrench (1) is placed on the nut on (a) side, the filter
will break.
• Assemble the filter so that opposite sides of the hexagonal
part of the filter fully engages with the flat surfaces of the
stopper (2).
(1) Wrench (9) Filter (Return)
(2) Stopper
RY9212166MBS0013US0
1-S17 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(3) Filter (Suction) Replacement Procedure
1. Remove the filter (return) from the tank.
(Refer to the chapter Filter (Return) Assembly/Disassembly.)
Remove the wiring harness clamps in three locations.
(1) Wiring Harness (2) Bolt (M10 × 16)
RY9212166MBS0079US0
2. Remove the bolt and the suction filter mounting pin (3).
(3) Pin (Suction)
RY9212166MBS0080US0
3. Hold onto the upper part of the filter (support) and remove the
filter (suction) (4) from the tank.
CAUTION
• Remove only the strainer (1) and when replacing with a new
part, set the overall length (A) to 380 mm (15 in.).
16 to 24 N·m
Tightening torque Nut (2) 1.6 to 2.4 kgf·m
12 to 18 lbf·ft
(1) Strainer (A) 380 mm (15 in.)
(2) Nut
(4) Filter (Suction)
RY9212166MBS0081US0
1-S18 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(4) Filter (Breather) Replacement Procedure
1. Loosen the bolt (1), and remove the washer (2).
(1) Bolt (2) Metal Washer
RY9212166MBS0082US0
2. Remove the filter (breather) (3) from the tank.
(3) Filter (Breather)
RY9212166MBS0083US0
1-S19 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(5) Assembly of Anti Vibration Support for the Hydraulic Oil Tank
(1) Stay
(2) Anti-Vibration Rubber
(3) Frame
(a) Bolt (M12 × 60)
(b) Bolt (M12 × 30)
RY9212166MBS0018US0
Tightening order for each bolt
1. Lightly tighten bolts (a) and (b) together with the assembly of their associated components.
2. Tighten in the order of (a)→(b).
3. Be sure the (a) bolt is assembled straight and not cross threaded.
77.5 to 90.2 N·m
Tightening torque Bolts (a)(b) 7.9 to 9.2 kgf·m
57.2 to 66.5 lbf·ft
Apply thread locking compound (Loctite 271) to (a).
RY9212166MBS0019US0
1-S20 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[5] ENGINE
(1) Engine Diassembly / Assembly
Removing the weight
1. Remove the weight.
(See "Weight Removal and Installation".)
(1) Weight
RY9212166MBS0044US0
Removing the cab
1. Disconnect the negative lead of the battery. Remove the cab.
(Refer to the chapter "Cab Removal and Installation".)
RY9212166MBS0053US0
Removing the fuel tank cover and centre bonnet.
1. Remove the cover of the fuel filler port.
2. Remove the centre bonnet.
(1) Fuel Tank Cover (2) Centre Bonnet
RY9212166MBS0054US0
Draining the coolant
1. Take off the radiator cap, remove the drain plug at the bottom of
the radiator and drain the coolant.
(1) Radiator (2) Drain Plug
RY9212166MBS0055US0
1-S21 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Removal of fuel hose, reserve tank and sedimenter bracket
1. Detach the fuel hose from the engine.
2. Remove the reserve tank.
3. Take out the sedimenter, with the bracket attached.
(1) Reserve Tank (2) Sedimenter Bracket
RY9212166MBS0056US0
Removing the arch
1. Remove the wire harness that is fixed to the arch, and the (7)
arch fixing bolts. Connect a nylon sling about the arch and hoist
with a crane.
123.6 to 147.1 N·m
Tightening torque Arch (1) 12.6 to 15.0 kgf·m
91.1 to 108.5 lbf·ft
Apply thread lock compound (Loctite 271).
(1) Arch
RY9212166MBS0057US0
Removal of the wire harness and air cleaner hose
1. Remove the wire harness about the engine.
2. Remove the air cleaner hose.
(1) Wire Harness (2) Air Cleaner Hose
RY9212166MBS0058US0
Remove the heater hose and compressor.
1. Detach the heater hose from the engine and plug the heater
hose.
Also remove the clamp which is fastened together with the
engine support.
2. Remove the compressor mounting bolts and disconnect from
the engine.
(1) Heater Hose (2) Compressor
RY9212166MBS0059US0
Removing the radiator hoses
1. Loosen the hose clamps on the upper and lower coolant hoses
and detach the hoses from the engine.
(1) Hose Clamp (Upper Hose) (2) Hose Clamp (Lower Hose)
RY9212166MBS0046US0
1-S22 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Removing the pump
1. Remove the pump mounting bolts and disconnect from the
pump connector. Stand pump on wooden block (2).
107.9 to 127.4 N·m
Tightening torque Pump, assy (1) 11.0 to 13.0 kgf·m
79.5 to 93.9 lbf·ft
(1) Pump, Assy (2) Block
RY9212166MBS0045US0
Removing the engine support bolts
1. Remove the engine suport fixing bolts. (4 places)
2. Detach the harness which is connected to the starter.
77.5 to 90.2 N·m
Tightening torque Support (engine) (2) 7.9 to 9.2 kgf·m
57.2 to 66.5 lbf·ft
(1) Bolt (M12 x 35) (2) Support (Engine)
RY9212166MBS0047US0
Removing the engine assembly
1. Attach two shackles to the engine, connect a nylon sling (1) to
these and support the engine using a crane.
(1) Nylon Sling
RY9212166MBS0048US0
1-S23 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(2) Engine Mount Installation
(1) Bracket (1, Engine) (5) Anti-Vibration Rubber (450) (9) Bolt (M16 X 70) (A) Front
(2) Bolt (M12 X 35) (6) Cap (10) Flat Metal Washer (B) Rear
(3) Bracket (2, Engine) (7) Bolt (M16 X 110) (11) Tray (Engine)
(4) Support (Engine) (8) Collar (12) Stay (Harness Coupler)
196.1 to 225.6 N·m
Tightening torque Bolt (7) 20 to 23 kgf·m
144.7 to 166.3 lbf·ft
Apply thread lock compound (Loctite 271) parts numbers (2), (7) and (9).
RY9212166MBS0020US0
1-S24 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(3) Arch, Air Cleaner
(1) Air Cleaner, Assy (5) Hose Clamp (with Screw) (9) Frame (a) Initially Installed on Inlet
(2) Inlet Hose 1 (6) Inlet Case (10) Frame 2 Case.
(3) Hose Clamp (with Screw) (7) Pipe (11) Bolt (M14, Arch)
(4) Inlet Hose 2 (8) Gasket (12) Collar
RY9212166MBS0021US0
Assembling the Arch
There is a counter bore in the arch mounting area on the swivel frame and it has a structure where a collar is
inserted and joined with the arch.
Be careful not to lose the collar when disassembling and reassembling and tighten using the following torque.
123.6 to 147.1 N·m
Tightening torque Bolt (11) 12.6 to 15.0 kgf·m
91.17 to 108.40 lbf·ft
Apply thread lock compound (Loctite 271).
RY9212166MBS0022US0
1-S25 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(4) Radiator
[A] Assembling of the Radiator
(1) Radiator, ASSY (4) Bracket (2, Radiator) (7) Hose (Lower, WP) (10) Band
(2) Rubber (Radiator Mount) (5) Shroud (Fan) (8) Coupler (Drain) (11) Tray (Engine Oil)
(3) Bracket (1, Radiator) (6) Hose (Upper, WP) (9) Hose (Drain) (a) Pass Through Hole
RY9212166MBS0023US0
Assembling the Shroud (fan)
4.5 to 5.5 N·m
Tightening torque Bolt (A) 0.46 to 0.56 kgf·m
3.4 to 4.0 lbf·ft
(1) Radiator, ASSY (a) Tolerance from Shroud (Fan) to
(2) Rubber (Radiator Mount) Fan : 30 ± 3 mm (1.2 ± 0.1 in.)
(3) Bracket (1, Radiator) (b) Gap between Fan and Shroud
(4) Bracket (2, Radiator) (Fan) at Least 10 mm (0.4 in.)
(5) Shroud (Fan) (c) Be sure that the Tab is Fully
Inserted into the Hole in the
(A) Bolt (M6 × 16) Bracket.
RY9212166MBS0024US0
1-S26 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(5) Oil Cooler
[A] Assembling of the Oil Cooler
(1) Oil Cooler
(2) Bracket (Oil Cooler)
(3) Bolt (M8 × 20)
(4) Flat Metal Washer
(5) Bolt (M8 × 25)
(6) Bolt (M8 × 20)
(7) Pipe Joint (Oil Cooler, L)
(8) Pipe Joint (Oil Cooler, R)
(9) Guide (Hose, PP)
(10) Cooler (Fuel)
RY9212166MBS0025US0
Oil cooler assembly procedure
1. Lightly tighten bolts (3), (5), and (6).
2. Tighten bolt (6).
17.7 to 20.6 N·m
Tightening torque Bolt (6) 1.8 to 2.1 kgf·m
13.1 to 15.1 lbf·ft
3. Tighten bolt (3).
9.8 to 11.3 N·m
Tightening torque Bolt (3) 1.0 to 1.15 kgf·m
7.3 to 8.3 lbf·ft
4. Tighten bolt (5).
23.5 to 27.5 N·m
Tightening torque Bolt (5) 2.4 to 2.8 kgf·m
17.4 to 20.2 lbf·ft
(3) Bolt (M6 × 14) (6) Bolt (M8 × 20)
(5) Bolt (M8 × 25)
RY9212166MBS0026US0
1-S27 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[6] DPF MUFFLER
(1) DPF Muffler Diassembly / Assembly
Removing the rear bonnet
1. Open the rear bonnet, remove the fixing bolts and detach the
rear bonnet.
(1) Rear Bonnet (2) Bolt (M10 x 25)
RY9212166MBS0066US0
Removing the left bonnet
1. Remove the left bonnet mounting bolts and the fuel tank cap,
and then remove the left bonnet.
(1) Left Bonnet (3) Bolt (M10 x 25)
(2) Bolt (M10 x 35)
RY9212166MBS0067US0
Removing the bracket and DPF guard
1. Remove the mounting bolts on the rear bonnet fixing bracket
and then remove the bracket.
2. Remove the DPF guard installation bolts and detach the DPF
guard.
(1) Bracket (2) DPF Guard
RY9212166MBS0068US0
Removing the DPF muffler pipe
1. Remove the DPF muffler pipe mounting bolts and then remove
the DPF muffler pipe.
(1) DPF Muffler Pipe (2) Bolt (M10 x 20)
RY9212166MBS0069US0
1-S28 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Removing the DPF muffler 1
CAUTION
• The DPF muffler remains hot, even after the engine has
been switched off. Allow the DPF muffler to cool
sufficiently before removing the connector.
1. Remove the three clamps and remove the connector 1.
2. Remove the connector 2 and the pressure sensor mounting
bolts.
3. Remove the nuts on the exhaust manifold section.
4. Remove the bolts fixing the DPF muffler and bracket.
23.5 to 27.5 N·m
Nut (3) 2.4 to 2.8 kgf·m
17.3 to 20.3 lbf·ft
Tightening torque
48.1 to 55.9 N·m
Bolt (4) 4.9 to 5.7 kgf·m
35.5 to 41.2 lbf·ft
(1) Connector 1 (Exhaust Temperature (4) Bolt (M10 x 30) Flat Washer Nut
Sensor)
(2) Connector 2 (Pressure Sensor)
(3) Nut
RY9212166MBS0070US0
Removing the DPF muffler 2
1. Remove the DPF muffler from the bracket.
IMPORTANT
• Weight of DPF muffler : approx. 13 kg (29 lbs)
• Take care of the sensors when removing the muffler. The
sensors can easily be broken by knocks.
• When reassembling the DPF muffler, loosen all of the DPF
support fixing bolts, and assemble the muffler following
the procedure described on the next page.
(1) DPF Muffler
RY9212166MBS0071US0
1-S29 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(2) DPF Muffler Assembly
(1) Muffler, Full Assy (A) Nut (D) Bolt (M10 x 35) (a) Front
(2) DPF Support (B) Bolt (M10 x 25) (E) Bolt (M10 x 30) (b) Insert Shim if there is a Gap
(3) DPF Bracket (C) Bolt (M12 x 25) (F) Bolt (M10 x 30) of 1.0 mm (0.04 in.) or More.
(4) Flat Metal Washer
[DPF muffler, full assy assembly procedure]
1. Gently tighten all of the bolts (A) to (F).
CAUTION
• Insert shim if there is a gap of 1.0 mm (0.04 in.) or more in part (E).
2. Tighten the exhaust manifold (A).
3. Tighten the DPF front side section (E).
4. Tighten the DPF rear side section (F).
5. Tighten the DPF support section (B).
6. Tighten the DPF support section (C).
7. Tighten the DPF front bracket section (D).
23.5 to 27.5 N·m
Nut (A) 2.4 to 2.8 kgf·m
17.3 to 20.3 lbf·ft
48.1 to 55.9 N·m
Tightening torque Bolt (B), (D), (E), (F) 4.9 to 5.7 kgf·m
35.5 to 41.2 lbf·ft
77.5 to 90.2 N·m
Bolt (C) 7.9 to 9.2 kgf·m
57.2 to 66.5 lbf·ft
RY9212166MBS0072US0
1-S30 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(3) Assembling of DPF Exhaust Pipe and DPF Cover
(1) DPF Pipe 1 (3) DPF Pipe 3 (5) Cover (a) Notch
(2) DPF Pipe 2 (4) Clamp (6) Guard
RY9212166MBS0073US0
Fixing position of clamp and DPF pipe 2
• Fix in centre of notch.
(a) Notch (b) Centre
RY9212166MBS0074US0
Insertion depth of DPF pipe 3 into DPF pipe 2
• To 2 to 3 mm from notch.
(a) Notch (b) 2 to 3 mm (0.08 to 0.10 in.)
RY9212166MBS0075US0
Gap between DPF pipe 1 and DPF pipe 3 (part B)
• (A) no less than 20 mm (0.79 in.)
(1) DPF Pipe 1 (3) DPF Pipe 3
RY9212166MBS0076US0
1-S31 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[7] ASSEMBLING OF OPERATING LEVERS
(1) Travel Lever
(1) Lever (Travel, Left) (a) 193 ± 5 mm (7.6 ± 0.2 in.)
(2) Lever (Travel, Right) (b) When in Neutral
(3) Bolt (M8 × 20) (c) To-and-fro Difference between
(4) Grip (Travel) Left and Right Levers should be
within 2.0 mm (0.08 in.)
(d) Gap between Left and Right
Levers : 11 to 22 mm (0.43 to
0.87 in.)
RY9212032MBS0031US0
Lever (travel, left), lever (travel, right) assembly
The pilot valve side is aluminum die cast so be careful not to
over tighten; tighten to the torques indicated below.
17.7 to 20.6 N·m
Tightening torque Bolt (3) 1.8 to 2.1 kgf·m
13.1 to 15.1 lbf·ft
(1) Lever (Travel, Left) (10) Flat Metal Washer
(2) Lever (Travel, Right) (11) Pedal Assy (Travel Left)
(3) Bolt (M8 × 20) (12) Pedal (Travel 2)
(4) Grip (Travel) (13) Pedal Assy (Travel Right)
(5) Washer Head Bolt (14) Headed Pin
(6) Valve, Assy (PV, Travel) (15) Flat Metal Washer
(7) Damper (HST) (16) Snap Pin
(8) Headed Pin (17) Bolt (M10 × 25)
(9) Snap Pin 8
RY9212032MBS0032US0
1-S32 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(2) Blade Lever
(1) Plate (Blade) A : Angle Version
(2) Bolt (M10x30)
(3) Lever (blade) (a) 62 mm (2.4 in.)
(4) Bolt (M12x25) (b) 39 mm (1.5 in.)
(5) Bolt (M10x25)
(6) Grip
(7) Button
RY9212050MBS0023US0
Assembling the lever (blade)
78 to 90 N·m
Tightening torque Bolt (4) 7.9 to 9.2 kgf·m
58 to 66 lbf·ft
(1) Plate (Blade) (6) Grip
(2) Bolt (M10x30) (7) Button
(3) Lever (blade) (8) Pan Head Machine Screw
(4) Bolt (M8x16)
(5) Bolt (M10x20) A : Angle Version
RY9212050MBS0024US0
Assembling the plate (blade)
48 to 55 N·m
Tightening torque Bolt (2) 4.9 to 5.7kgf·m
35 to 41 lbf·ft
RY9212050MBS0022US0
1-S33 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
3. TRACK FRAME
[1] ASSEMBLING OF SWIVEL BEARING
(1) Swivel bearing assembly procedure
1. Component names
No. in
Component names Q'ty
Figure
(1) Bearing (swivel) 1
(2) Bolt (M16 × 60) 24
(3) Diaphragm spring 48
(4) Bolt (M16 × 55) 24
2. Assembly position
Mount the inner tire soft zone ('S' mark) (d) on the right side of
the body.
3. Swivel bearing tightening torque
After lightly tightening, tighten to the torque indicated below
from a diagonal angle.
259.9 to 304.0 N·m
Tightening torque Swivel bearing (1) 26.5 to 31.0 kgf·m
191.7 to 224.0 lbf·ft
Apply thread lock compound. (Loctite 271)
4. Apply grease to the tooth surfaces
Apply grease so that it covers the entire bearing teeth surfaces.
(a) Ball Insert Groove (External Tire A : Rear of Vehicle
Soft Zone) B : Front of Vehicle
(b) Tooth Surface Grease
Application Zone
(c) Port for Applying Grease to the
Ball (Mate with Hole in Swivel
Frame)
(d) 'S' Mark
RY9212032MBS0003US0
(2) Swivel bearing external dimensions
No. in
Size
Figure
A 60 mm (2.4 in.)
B 47 mm (1.8 in.)
C 770 mm ( 30.3 in.)
D P.C.D. 742 mm (P.C.D. 29.2 in.)
E 689 mm ( 27.1 in.)
F P.C.D. 638 mm (P.C.D. 25.1 in.)
G 610 mm ( 24 in.)
H P.C.D. 588 mm (P.C.D. 23.1 in.)
I 574 mm ( 22.6 in.)
RY9212032MBS0004US0
1-S34 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(3) Measuring the swivel bearing play
1. Attach the dial gauge and the dial gauge fixture on the machine
front. (Measurement position differs with the machine model.)
2. Fully stretch the arm and place the bucket in the crowded
position. Set the dial gauge to the zero point.
3. Using the attachment, tilt up the machine body, and take the dial
gauge reading. Make this measurement several times and take
their average as the final measurement.
CAUTION
• Perform the measurement three times, determine the
average value, and take this as the measured value.
1.08 mm
Factory KX057-4
0.04 in.
specifica-
tion 1.28 mm
U55-4
(L) : 20 mm (0.79 in.) 0.05 in.
away from swivel race 2.16 mm
KX057-4
Allowable 0.09 in.
limit 2.56 mm
U55-4
0.10 in.
(L) Measurement Position
RY9212166MBS0027US0
1-S35 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[2] TRACK
(1) Assembly / Disassembly of Rubber Track
CAUTION
• The pressure in the grease cylinder is high so if loosened quickly, the nipple may pop off and the highly
pressurized grease in the cylinder may fly out. Do not put your face near the nipple or place your body in
front of the nipple, and be sure to loosen the nipple gradually.
• The rubber track is heavy and must be handled with care.
RY9212182MBS0071US0
Removing the grease nipple
1. Place a wrench (socket) at the base of the grease nipple and
loosen slowly.
If there are any rocks or the like caught in the sprocket, remove
the rocks first.
98.0 to 107.8 N·m
Tightening torque Grease nipple 10 to 11 kgf·m
72.0 to 79.5 lbf·ft
(1) Grease Nipple
RY9212182MBS0057US0
Loosen track
1. Jack up the body using the front end and blade, expel grease
from inside the grease cylinder, and fully loosen up the track.
When the track loosens up, attach the grease nipple.
RY9212032MBS0008US0
Removing the rubber tracks
1. With the machine lifted slightly, wedge a steel pipe into the track
and turn the sprocket backwards in direction A.
When the steel pipe reaches halfway up the idler and the track
lifts off the idler, stop turning the sprocket and slide the track
sideways in direction B to remove it.
• Weight of rubber track: approximately 240 kg (529 lbs)
A : Backwards B : Direction to Slide
RY9212166MBS0042US0
Assembling the rubber tracks
1. Jack up the machine with the front attachments and the blade
slightly off the ground, wedge the track onto the sprocket and
set it on the frame.
2. Wedge steel pipes into the track and rotate the sprocket
backwards in direction A. When a steel pipe reaches halfway up
the idler, stop turning the sprocket. Slide the track sideways in
direction B and set the track onto the idler. Lower the machine
and drive it backwards to make sure the tracks are on securely.
Adjust the tension of the track.
CAUTION
• Be sure to assemble the rubber track the right way round.
A : Backwards B : Direction to Slide
RY9212182MBS0102US0
1-S36 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
(2) Assembly / Disassembly of Iron Tracks
CAUTION
• The pressure in the grease cylinder is high so if loosened quickly, the nipple may pop off and the highly
pressurized grease in the cylinder may fly out so do not get your face near the nipple nor place your body
in front of the nipple and loosen the nipple gradually.
RY9212001MBS0008US0
Removing the grease nipple
1. Remove one bolt (2) and then the cover (1).
2. Place a wrench (socket) at the base of the grease nipple and
loosen slowly.
If there is a rock etc. caught in the sprocket, remove the rock
first.
(1) Cover (3) Grease Nipple
(2) Bolt (M10)
RY9212001MBS0009US0
Loosen track
1. Jack up the body using the front end and blade, expel grease
from inside the grease cylinder, and fully loosen up the track.
When the track loosens up, attach the grease nipple.
RY9212032MBS0008US0
Removing the locking pin
1. Turn the track until the master pin (1) is in front of the front idler.
2. Remove the locking pin (3) from the master pin.
(1) Master Pin (3) Locking Pin
(2) Master Link
RY9212001MBS0103US0
1-S37 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Removing the master pin
1. Place a jig on the master pin and tap it out with a hammer.
Use a jig as shown in the diagram to the left for removing the
pin.
(1) Hammer (3) Block
(2) Jig
RY9212001MBS0104US0
Removing the shoe
1. Slowly move the travel lever to the backup position and back up
the mini-excavator.
2. Jack up the mini excavator using the front end and blade and
pull off the shoe.
DANGER
• Do not place feet under the mini excavator.
• Weight of iron track : approximately 285 kg (628 lbs)
RY9212166MBS0028US0
1-S38 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Mounting an iron track
1. Jack up the mini excavator using the front end and blade and
place the track so that the end of the track meshes with the
sprocket under the mini excavator.
Make sure the track is placed in the correct orientation.
(1) Master Link (a) Sprocket Side
(b) Front Idler Side
RY9212001MBS0106US0
2. Raise the track using a crane and mesh it with the sprocket
teeth.
(4) Sprocket
RY9212001MBS0107US0
3. Slowly move the travel lever to the forward travel position to
mesh the track with the shoe (6).
When the track is sufficiently pulled on to where the track link
joint is at the front idler, lower the mini-excavator, and place a
block (7) under the shoe to support the shoe.
Match up both ends of the shoe, insert the master pin from the
outside of the body, insert the locking pin and bend the tip.
(5) Idler (7) Block
(6) Shoe
RY9212001MBS0108US0
1-S39 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[3] RUBBER CRAWLER
Identification mark
∞
(Core metal lapping position)
19 mm
(1) Lug height
0.75 in.
25 mm
(2) Link height
0.96 in.
400 mm
(3) Crawler width
15.75 in.
10 to 15 mm
(4) Crawler sag distance
0.39 to 0.59 in.
91.0 mm
(5) Crawler height
3.58 in.
Number of core metal 74
5365 mm
Circumference
211.2 in.
72.5 mm
Core metal pitch
2.85 in.
RY9212050GEG0006US0
[4] STEEL CRAWLER
STD Wide
400 mm 550 mm
Crawler width
15.75 in. 21.65 in.
540 / 548 mm
(1) 4 links length (a)/(b)
21.26 / 21.57 in.
67.0 mm
(2) Height
2.64 in.
20.0 mm
(3) Grouser height
0.79 in.
35.0 / 34.0 mm
(4) Bushing O. D. (a)/(b)
1.38 / 1.34 in.
22.5 / 23.5 mm
(5) Bushing I. D. (a)/(b)
0.89 / 0.93 in.
22.15 / 21.5 mm
(6) Master pin O. D. (a)/(b)
0.87 / 0.83 in.
80 to 85 mm
(7) Crawler sag distance
3.15 to 3.35 in.
Number of links 39
(a) New machine reference value
(b) Allowable limit
RY9212050GEG0007US0
1-S40 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[5] FRONT IDLER
(1) Assembly/Disassembly of Front Idler
Removing the idler
1. Remove the track.
(Refer to the chapter "Track Assembly/Disassembly".)
Jack up the mini-excavator with the front-end and the blade and
place timbers etc. under the frame.
2. Using a bar, remove the front idler from the track frame along
with the yoke.
• Front idler assy weight : approximately 46 kg (100 lbs)
(1) Block
RY9212032MBS0035US0
(2) Front Idler Structural Components
No. Component names Q'ty
(1) Spring Pins 1
(2) Bracket (R) 1
(3) Shaft (idler) 1
(4) Idler 1
(5) Floating Seal 2
(6) Bushing 1
(7) External circlip 2
(8) O-Ring 2
(9) Bracket (L) 1
(10) Plate (yoke) 1
(11) Bolt 4
(12) Plug (R1/8) 1
RY9212001MBS0112US0
1-S41 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[6] SPRING ASSY
(1) Assembly/Disassembly of Spring Assy
Removing the spring assy
1. Remove the track and the front idler.
(Refer to the "Track and Front Idler" chapters for
assembly/disassembly of the track and front idler.)
After removing the front idler assy, pull out the spring assy (1)
from the track frame.
• Spring assy weight : approximately 17 kg (37 lbs)
(1) Spring Assy
RY9212166MBS0029US0
Rubber track specification
No. Component names Q'ty
(1) Bolt (spring) 1
(2) Spring 1
(3) Retainer (spring) 1
(4) Slotted nut 1
(5) Cotter pin 1
(a) Set Length for Rubber Track :
227.5 mm (8.96 in.)
(b) Make sure the Cotter Pin is Set in the Groove
of the Slotted Nut
(c) Set Position for Iron Track Specifications
RY9212166MBS0030US0
Iron track specifications
No. Component names Q'ty
(1) Bolt (spring) 1
(2) Spring 1
(3) Retainer (spring) 1
(4) Slotted nut 1
(5) Cotter pin 1
(a) Set Length for Iron Track : 242.5 mm (9.55 in.)
(b) Make sure the Cotter Pin is Set in the Groove
of the Slotted Nut
(c) Set Position for Rubber Track Specification
RY9212166MBS0031US0
1-S42 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[7] CYLINDER ASSEMBLY
(1) Assembly/Disassembly of Cylinder Assy
Removing the cylinder assy
1. Remove the track, front idler, and spring assy.
(Refer to the spring idler chapter for assembly/disassembly of
the track, front idler, and spring assy.)
After removing the spring assy, pull out the cylinder assy (1)
from the track frame.
• Cylinder assy weight : approximately 14 kg (31 lbs)
(1) Cylinder Assembly
RY9212166MBS0032US0
(2) Cylinder Assembly Structural Components
No. Component names Q'ty
(1) Rod 1
(2) Rod seal 1
(3) Backup ring 1
(4) O-Ring 1
(5) Cylinder tube 1
(6) Nipple, assy 1
98.0 to 107.8 N·m
Tightening torque Nipple, assy (6) 10 to 11 kgf·m
73.0 to 79.5 lbf·ft
RY9212166MBS0033US0
Rubber track specification structural components
No. Component names
(1) Idler assy
(2) Spring assy
(3) Cylinder assembly
(a) 227.5 mm (8.96 in.)
RY9212166MBS0034US0
Iron track specification structural components
No. Component names
(1) Idler assy
(2) Spring assy
(3) Cylinder assembly
(a) 242.5 mm (9.55 in.)
RY9212166MBS0035US0
1-S43 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Mounting an iron track guide
Tightening torque for iron track guide mounting bolt (2).
103.0 to 117.7 N·m
Tightening torque Guide (1) 10.5 to 12.0 kgf·m
76.0 to 86.8 lbf·ft
Apply thread lock compound (Loctite 271).
(1) Guide (2) Bolt (Diaphragm Spring Flat
Washer)
RY9212166MBS0036US0
1-S44 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[8] TRACK ROLLER
(1) Assembly/Disassembly of Track Roller
CAUTION
• The pressure in the grease cylinder is high so if loosened quickly, the nipple may pop off and the highly
pressurized grease in the cylinder may fly out so do not get your face near the nipple nor place your body
in front of the nipple and loosen the nipple gradually.
RY9212001MBS0008US0
Removing the grease nipple
1. Remove one bolt (2) and then the cover (1).
2. Place a wrench (socket) at the base of the grease nipple and
loosen slowly.
If there is a rock etc. caught in the sprocket, remove the rock
first.
(1) Cover (3) Grease Nipple
(2) Bolt (M10)
RY9212001MBS0009US0
Loosen track
1. Jack up the body using the front end and blade, expel grease
from inside the grease cylinder, and fully loosen up the track.
When the track is loose, attach the grease nipple and place a
block under the track frame.
RY9212032MBS0036US0
Removing the track roller
1. Loosen the track roller mounting bolt, and remove the track
roller.
Track roller weight : 10 kg (22 lbs)
RY9212166MBS0037US0
1-S45 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Mounting the track roller
(1) Track Roller, Assy (2) Bolt (3) Flat Metal Washer (a) Less than 1.5 mm (0.06 in.)
(Gap between Working
Surfaces)
Please perform the procedure in reverse for assembly.
259.9 to 304.0 N·m
Tightening torque Track roller assy 26.5 to 31.0 kgf·m
191.7 to 224.2 lbf·ft
Thread locking compound : Three Bond 1305P
Apply the thread locking compound to the female threads.
RY9212166MBS0038US0
(2) Track Roller Structural Components
No. Component names Q'ty No. Component names Q'ty
1 Shaft assy 1 7 Track roller (body) 1
2 Shaft (track roller) 1 8 Seal (floating) 2
3 Bracket (track roller) 1 9 O-Ring 1
4 Plug (R1/8) 1 10 Bracket (track roller) 1
5 Track roller 1 11 Wire 1
6 Bushing 2
RY9212001MBS0120US0
1-S46 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[9] CARRIER ROLLER
(1) Assembly/Disassembly of Carrier Roller
CAUTION
• The pressure in the grease cylinder is high so if loosened quickly, the nipple may pop off and the highly
pressurized grease in the cylinder may fly out so do not get your face near the nipple nor place your body
in front of the nipple and loosen the nipple gradually.
RY9212001MBS0008US0
Removing the grease nipple
1. Remove one bolt (2) and then the cover (1).
2. Place a wrench (socket) at the base of the grease nipple and
loosen slowly.
If there is a rock etc. caught in the sprocket, remove the rock
first.
(1) Cover (3) Grease Nipple
(2) Bolt (M10)
RY9212001MBS0009US0
Loosen track
1. Jack up the body using the front end and blade, expel grease
from inside the grease cylinder, and fully loosen up the track.
When the track is loose, attach the grease nipple and place a
block under the track frame.
RY9212032MBS0036US0
1-S47 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
Removing the carrier roller
1. Insert a block (2) into the gap between the carrier roller and the
track.
2. Loosen the nut (3) and remove the carrier roller (1).
Carrier weight : approximately 4 kg (9 lbs)
(1) Carrier Roller (3) Nut
(2) Block
RY9212032MBS0037US0
Mounting the carrier roller
Please perform the procedure in reverse for assembly.
77.5 to 90.2 N·m
Tightening torque Carrier roller assy 7.9 to 9.2 kgf·m
57.2 to 66.5 lbf·ft
Apply thread locking compound : (Loctite 271)
(1) Carrier Roller, Assy (3) Spring Washer
(2) Bolt (4) Nut
RY9212166MBS0039US0
(2) Carrier Roller Structural Components
No. Component names Q'ty
1 Roller 1
2 Shaft 1
3 Shaft seal 1
4 Ball bearing 2
5 Ring stopper 1
6 Cap seal 1
7 Spacer 1
8 Plug 1
RY9212001MBS0123US0
1-S48 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM MACHINE BODY
[10] TRUCK ROLLER, IDLER AND SPROCKET DIMENSIONS
Remarks
330 / 294 mm
(1) Idler O.D. (a) / (b)
13 / 11.6 in.
52 / 46 mm
(2) Guide width (a) / (b)
2.05 / 1.8 in.
93 mm
(3) Idler width
3.66 in.
Sprocket wheel O.D. (a) / 429 / 417 mm
(4)
(b) 16.89 / 16.4 in.
43 mm
(5) Sprocket wheel width
1.69 in.
(A) Idler (a) Standard Value when New
(B) Sprocket (b) Allowable Limit
RY9212166MBS0084US0
Remarks
85 / 77 mm
(1) Guide diameter (a) / (b)
3.35 / 3.0 in.
135 / 117 mm
(2) Outer diameter (a) / (b)
5.31 / 4.61 in.
200 mm
(3) Roller width
7.87 in.
Carrier roller diameter (a) / 80 / 74 mm
(4)
(b) 3.15 / 2.91 in.
(A) Truck Roller (a) Standard Value when New
(B) Carrier Roller (b) Allowable Limit
RY9212166MBS0085US0
1-S49 KiSC issued 04, 2021 A
2 ENGINE
KiSC issued 04, 2021 A
GENERAL
CONTENTS
1. SPECIFICATIONS...................................................................................................................... 2-G1
2. EXTERNAL DIMENSIONS ......................................................................................................... 2-G2
3. LAYOUT OF MAIN PARTS ........................................................................................................ 2-G3
4. PERFORMANCE CURVE .......................................................................................................... 2-G4
5. FAN DRIVE................................................................................................................................. 2-G5
KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ENGINE
1. SPECIFICATIONS
KX057-4, U55-4
Model V2607-CR-E4-BH1 V2607-CR-E4-BH2
No. of cylinders 4
Cylinder Bore X Stroke 87.0 × 110 mm (3.43 × 4.33 in.)
Total displacement 2615 cm3 (159.6 cu.in.)
Idling RPM 1100 min-1
Rated RPM 2200 min-1
Maximum RPM 2300 min-1
34.5 kW / 2200 min-1 33.8 kW / 2200 min-1
Net
Rated output/RPM (46.2 HP / 2200 min-1) (45.3 HP / 2200 min-1)
Gross 35.5 kW / 2200 min-1 (47.6 HP/ 2200 min-1)
170.7 N·m / 1500 min-1 169.7 N·m / 1500 min-1
Net (17.40 kgf·m / 1500 min-1) (17.30 kgf·m / 1500 min-1)
(125.9 lbf·ft / 1500 min-1 ) (125.2 lbf·ft / 1500 min-1 )
Max torque/RPM
174.1 N·m / 1500 min-1
Gross (17.75 kgf·m / 1500 min-1)
(128.4 lbf·ft / 1500 min-1 )
Machine dimensions (L x W x H) 691 x 535 x 731 mm (27.2 x 21.1 x 28.8 in.)
Dry weight 267 kg (589 lbs)
Combustion type Re-entrant, direction injection type (E-CDIS)
Fuel injection pump type
Governor type
Nozzle type Denso common rail system
Fuel injection timing
Fuel injection pressure
Rotation direction Counterclockwise viewed from flywheel side
Firing order 1-3-4-2
Compression ratio 18
EGR External EGR
Compression pressure 3.2 MPa (33 kgf/cm2, 464 psi)
Fuel consumption (at Net –
rated RPM) Gross 221.8 g/kW·h (165.4 g/HP·h, 0.365 lb/HP·h)
Engine oil consumption (at rated RPM) 0.54 g/kW·h (0.40 g/PS·h) or less
Alternator 12 V, 720 W
Battery JIS 12V72AH, 115D31L
Starter motor 12 V, 2.0 W
* Fan drive specifications, so stated net value is same as E3.
RY9212166END0001US0
2-G1 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ENGINE
2. EXTERNAL DIMENSIONS
A 690.7 mm (27.19 in.) G 296.5 mm (11.67 in.)
B 321 mm (12.6 in.) H 10 mm (0.39 in.)
C 8.4 mm (0.33 in.) I 730.7 mm (28.77 in.)
D 80 mm (3.1 in.) J 233.1 mm (9.17 in.)
E 160 mm (6.3 in.) K 290 mm (11.4 in.)
F 534.5 mm (21.04 in.) L 160 mm (6.3 in.)
RY9212166END0002US0
2-G2 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ENGINE
3. LAYOUT OF MAIN PARTS
No. Name of part No. Name of part
(1) Injector (10) Starter
(2) Fan drive (11) SCV (front)
(3) EGR valve (12) Fuel temperature sensor (rear)
(4) EGR cooler (13) Oil filter
(5) Intake throttle valve (14) Alternator
(6) Water temperature sensor (15) Rail pressure sensor
(7) Common rail (16) Blow-by gas filter
(8) NE sensor (17) G sensor
(9) Supply pump
RY9212166END0003US0
2-G3 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ENGINE
4. PERFORMANCE CURVE
(a) Engine RPM (rpm) (d) Fuel Consumption (g/kW·h) (f) Torque (ft·lb) A : SI Unit
(b) Output (kW) (e) Output (HP) (g) Fuel Consumption (g/HP·h) B : Industrial Unit of the United
(c) Torque (N·m) States
RY9212166END0004US0
2-G4 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ENGINE
5. FAN DRIVE
(1) Bimetallic Strip (4) Feed Orifice (6) Collection Orifice A : At High Temperature
(2) Piston (5) Torque Transmission (7) Oil Collection Chamber B : At Low Temperature
(3) Flat Spring (Valve) Chamber
[At high temperature]
• When the temperature rises, the bimetallic strip (1) bends slightly, opening the supply orifice (4) via the linkage
of the piston (2) and the valve (3).
• Silicon oil flows from the supply orifice (4) into the torque transmission chamber (5), increasing the transmitted
torque and increasing fan RPM.
[At low temperature]
• The supply orifice (4) closes and oil is not supplied to the torque transmission chamber (5).
• As the part colored in blue is directly coupled to the engine, it rotates at the same speed as the engine.
Conversely, the fan drive body turns at a lower RPM as there is little oil remaining in the torque transmission
chamber (5) (The blue part turns at high RPM and the fan body turns at low speed).
• The oil from the torque transmission chamber (5) returns to the oil collection chamber (7) via the collection orifice
(6).
RY9212148END0004US0
2-G5 KiSC issued 04, 2021 A
3 HYDRAULIC SYSTEM
KiSC issued 04, 2021 A
MECHANISM
CONTENTS
1. DIAGRAM OF HYDRAULIC CIRCUIT [KX057-4, U55-4 STANDARD SPECIFICATION
(ANGLE BLADE OPTION)]......................................................................................................... 3-M1
2. HYDRAULIC DEVICE LAYOUT ................................................................................................. 3-M2
3. PUMP ......................................................................................................................................... 3-M3
[1] PUMP WITH LS CONTROL FUNCTIONS ........................................................................... 3-M3
(1) Specifications ................................................................................................................. 3-M3
(2) Function and Structure ................................................................................................... 3-M7
4. CONTROL VALVE.................................................................................................................... 3-M14
[1] SPECIFICATIONS.............................................................................................................. 3-M14
[2] DIAGRAM OF HYDRAULIC CIRCUIT ............................................................................... 3-M17
[3] FUNCTION AND STRUCTURE ......................................................................................... 3-M17
(1) Independent Travel Circuit ........................................................................................... 3-M17
(2) When Traveling Independently (Operation of Left/Right Forward Travel) .................... 3-M18
(3) When Operating Multiple Functions (Travel and Front-End Operation(s)) ................... 3-M20
(4) Front-End Operation..................................................................................................... 3-M21
(5) Compensator Spool (Pressure Compensator Valve) ................................................... 3-M24
5. SWIVEL MOTOR...................................................................................................................... 3-M25
[1] SPECIFICATIONS.............................................................................................................. 3-M25
[2] COMPONENTS .................................................................................................................. 3-M26
[3] FUNCTION AND STRUCTURE ......................................................................................... 3-M28
(1) Operating Principles ..................................................................................................... 3-M28
(2) Make Up Circuit ............................................................................................................ 3-M28
(3) Shockless Valves ......................................................................................................... 3-M29
(4) Parking Brake ............................................................................................................... 3-M30
6. TRAVEL MOTOR ..................................................................................................................... 3-M31
[1] SPECIFICATIONS.............................................................................................................. 3-M31
[2] COMPONENTS .................................................................................................................. 3-M32
[3] FUNCTION AND STRUCTURE ......................................................................................... 3-M34
(1) Operating Principles ..................................................................................................... 3-M34
(2) Counter-Balance Valve................................................................................................. 3-M34
(3) Anti-Cavitation Valve .................................................................................................... 3-M36
(4) Auto-Decelerator Function............................................................................................ 3-M38
(5) Parking Brake ............................................................................................................... 3-M39
(6) Decelerator ................................................................................................................... 3-M40
7. HYDRAULIC CYLINDER.......................................................................................................... 3-M41
[1] BOOM CYLINDER ............................................................................................................. 3-M41
(1) Specifications ............................................................................................................... 3-M41
(2) Components ................................................................................................................. 3-M41
(3) Function and Structure ................................................................................................. 3-M42
[2] ARM CYLINDER ................................................................................................................ 3-M43
(1) Specifications ............................................................................................................... 3-M43
(2) Components ................................................................................................................. 3-M43
(3) Function and Structure ................................................................................................. 3-M44
[3] BUCKET CYLINDER .......................................................................................................... 3-M45
(1) Specifications ............................................................................................................... 3-M45
(2) Components ................................................................................................................. 3-M45
[4] SWING CYLINDER ............................................................................................................ 3-M46
(1) Specifications ............................................................................................................... 3-M46
(2) Components ................................................................................................................. 3-M46
KiSC issued 04, 2021 A
[5] BLADE CYLINDER ............................................................................................................. 3-M47
(1) Specifications................................................................................................................ 3-M47
(2) Components ................................................................................................................. 3-M47
[6] ANGLE CYLINDER ............................................................................................................ 3-M48
(1) Specifications................................................................................................................ 3-M48
(2) Components ................................................................................................................. 3-M48
8. PILOT VALVE ........................................................................................................................... 3-M49
[1] PILOT VALVE (BOOM, ARM, BUCKET, SWIVEL) ............................................................ 3-M49
(1) Specifications................................................................................................................ 3-M49
(2) Components ................................................................................................................. 3-M51
(3) Function and Structure ................................................................................................. 3-M52
[2] PILOT VALVE (TRAVEL) ................................................................................................... 3-M53
(1) Specifications................................................................................................................ 3-M53
(2) Components ................................................................................................................. 3-M54
(3) Function and Structure ................................................................................................. 3-M55
[3] PILOT VALVE (SWING) ..................................................................................................... 3-M57
(1) Specifications................................................................................................................ 3-M57
(2) Components ................................................................................................................. 3-M58
(3) Function and Structure ................................................................................................. 3-M59
[4] PILOT VALVE (BLADE)...................................................................................................... 3-M60
(1) Specifications................................................................................................................ 3-M60
(2) Components ................................................................................................................. 3-M61
(3) Function and Structure ................................................................................................. 3-M62
9. UNLOAD VALVE ...................................................................................................................... 3-M64
[1] SPECIFICATIONS .............................................................................................................. 3-M64
[2] COMPONENTS .................................................................................................................. 3-M65
[3] FUNCTION AND STRUCTURE ......................................................................................... 3-M66
(1) Function ........................................................................................................................ 3-M66
(2) Operation ...................................................................................................................... 3-M66
10. SOLENOID VALVE................................................................................................................... 3-M68
[1] SOLENOID VALVE FOR ANGLE BLADE .......................................................................... 3-M68
(1) Specifications................................................................................................................ 3-M68
(2) Components ................................................................................................................. 3-M68
(3) Function and Structure ................................................................................................. 3-M69
[2] SOLENOID VALVE FOR AUX............................................................................................ 3-M70
(1) Specifications................................................................................................................ 3-M70
(2) Components ................................................................................................................. 3-M72
(3) Function and Structure ................................................................................................. 3-M74
[3] EP MODE SOLENOID VALVE ........................................................................................... 3-M81
(1) Specifications................................................................................................................ 3-M81
KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
1. DIAGRAM OF HYDRAULIC CIRCUIT [KX057-4, U55-4 STANDARD SPECIFICATION (ANGLE BLADE OPTION)]
3-M1 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
2. HYDRAULIC DEVICE LAYOUT
(1) Pump (7) Arm Cylinder (13) Pilot Valve (Blade) (18) AUX 2 (Thumb)
(2) Control Valve (8) Bucket Cylinder (14) Pilot Valve (Swing) (19) Angle Cylinder
(3) Swivel Motor (9) Swing Cylinder (15) Unload Valve (20) Solenoid Valve (ANG)
(4) Swivel Joint (10) Blade Cylinder (16) Solenoid Valve (21) TPSS Valve
(5) Travel Motor (11) Pilot Valve (Control) (AUX1 / AUX2 (Thumb)) (22) EP Mode Solenoid Valve
(6) Boom Cylinder (12) Pilot Valve (Travel) (17) AUX1
RY9212050HYM0009US0
3-M2 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
3. PUMP
[1] PUMP WITH LS CONTROL FUNCTIONS
(1) Specifications
(1) Variable Pump (Piston Pump) (3) Gear Pump (Pilot Pump) (6) P1 Port (9) Port T
(P1, P2) (4) L/S Regulator (7) P2 Port (10) PPS Port
(2) Gear Pump P3 (5) PS Port (Section) (8) P3 Port (11) PLS Port
RY9212166HYM0001US0
3-M3 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Specifications of pump
Notes
Maker KYB
Pump type PSVL2-27CG
Max. Shaft speed 2200 rpm
Main relief 27.4 MPa
pressure 280 kgf/cm2
a LS 3983 psi
Main relief 26.5 MPa
pressure 270 kgf/cm2 at travel open
a TR/TL 3843 psi
Max. Pressure
Main relief 19.1 MPa
pressure 195 kgf/cm2
a P3 2770 psi
3.92 MPa
Pilot pump 40 kgf/cm2
569 psi
Split flow of variable
displacement piston pump
Main pump 25.5 / 25.5 cc/rev
At 1000 rpm
P1/P2 1.56 / 1.56 cu.in./rev
5.2 x 2 cc/rev
Max. Displacement (0.32 x 2 cu.in./rev)
Main pump 16.8 cc/rev
Gear pump
P3 1.03 cu.in./rev
Pilot pump 7.1 cc/rev
Gear pump
Pp 0.43 cu.in./rev
Main pump 56.1 / 56.1 L/min
P1/P2 14.82 / 14.82 USGPM
Main pump 37.0 L/min
Max. Pump flow
P3 9.78 USGPM
Pilot pump 15.6 L/min
Pp 4.12 USGPM
1.65 MPa Engine rpm proportional control
Flow amount (pump) control LS control
16.8 kgf/cm2 with P4, Idling / Rated = about
differential pressure valve
239 psi 50 - 70 %
10.4 to 22.9 L/min
Standby flow rate At 1000 to 2200 rpm
2.75 to 6.04 USGPM
PC horsepower control valve: With P3 horsepower shift
Swash plate control aided by self-tilting moment (Small piston
Horsepower control
deleted.)
P1 + P2 pressure: Average pressure by orifice
Bearing: Cradle
Structure Shoe plate: Spherical
Large-diameter piston (with shoe)
RY9212166HYM0002US0
3-M4 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Piston pump power constant characteristics 1 (Bench test values)
(1) Pi = 3.6 MPa (PA, QA) (2) Pi = 0 MPa (PB, QB) (a) Discharge Flow Rate : Q (b) Discharge Pressure : P
(L/min) (MPa)
Pump input RPM : 2200 rpm
Gear pump pressure : P3 = 2 MPa Gear pump pressure : P3 = 2 MPa
Pi pressure : Pi = 3.6 MPa Pi pressure : Pi = 0 MPa
Pump input torque : 131 to 134 N·m Pump input torque : 72 to 87 N·m
Discharge pressure (MPa) Discharge flow rate (L/min) Discharge pressure (MPa) Discharge flow rate (L/min)
PA = 2.0 QA = 111.1 ±3.3 PB = 4.4 QB = 110.5 ±3.3
PA = 12.7 QA = 108.5 (target value) PB = 5.3 QB = 110.2 (target value)
PA = 17.3 QA = 63.7 (target value) PB = 9.5 QB = 66.4 (target value)
PA = 27.4 QA = 28.5 ±10.3 PB = 24.1 QB = 20.0 (target value)
PB = 27.4 QB = 18.0 + 10.3, – 4.2
PA1 = 2.0 QA1 = 111.1 ±3.3 PB1 = 4.4 QB1 = 110.5 ±3.3
PA2 = 4.4 QA2 = 110.5 ±3.3 PB2 = 6.4 QB2 = 99.4 ±9.8
PA3 = 11.6 QA3 = 108.8 ±3.9 PB3 = 8.2 QB3 = 80.8 ±10.3
PA4 = 14.8 QA4 = 89.8 ±8.4 PB4 = 11.2 QB4 = 61.2 ±10.3
PA5 = 16.0 QA5 = 76.2 ±9.8 PB5 = 22.6 QB5 = 24.8 ±10.3
PA6 = 19.0 QA6 = 57.6 ±10.3 PB6 = 27.4 QB6 = 18.0 + 10.3, – 4.2
PA7 = 27.4 QA7 = 28.5 ±10.3
RY9212166HYM0009US0
3-M5 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Piston pump power constant characteristics 2 (Bench test values)
(1) Pi = 3.6 MPa (PA, QA) (2) Pi = 0 MPa (PB, QB) (a) Discharge Flow Rate : Q (b) Discharge Pressure : P
(L/min) (MPa)
Pump input RPM : 2200 rpm
Gear pump pressure : P3 = 19.1 MPa Gear pump pressure : P3 = 19.1 MPa
Pi pressure : Pi = 3.6 MPa Pi pressure : Pi = 0 MPa
Pump input torque : 147 N·m max. Pump input torque : 147 N·m max.
Discharge pressure (MPa) Discharge flow rate (L/min) Discharge pressure (MPa) Discharge flow rate (L/min)
PA = 2.0 QA = 111.1 ±3.3 PB = 2.0 QB = 97.6 ±10.3
PA = 7.5 QA = 110.3 (target value) PB = 4.5 QB = 68.8 (target value)
PA = 12.1 QA = 64.8 (target value) PB = 18.7 QB = 23.0 (target value)
PA = 27.4 QA = 18.5 + 10.3, – 4.8 PB = 27.4 QB = 17.4 + 10.3, – 4.2
PA1 = 2.0 QA1 = 111.3 ±3.3 PB1 = 2.0 QB1 = 97.6 ±10.3
PA2 = 6.2 QA2 = 110.4 ±10.3 PB2 = 3.5 QB2 = 80.2 ±10.3
PA3 = 9.2 QA3 = 93.1 ±10.3 PB3 = 5.5 QB3 = 65.6 ±10.3
PA4 = 10.7 QA4 = 78.1 ±10.3 PB4 = 17.2 QB4 = 27.8 ±10.3
PA5 = 13.7 QA5 = 59.6 ±10.3 PB5 = 21.5 QB5 = 21.8 + 10.3, – 8.6
PA6 = 27.4 QA6 = 18.5 ±10.3, -4.8 PB6 = 27.4 QB6 = 17.4 + 10.3, – 4.2
RY9212166HYM0010US0
Diagram of Hydraulic Circuit
P1/P2: Piston Pump Discharge PPS: Valve Inlet Pressure
Pressure PS: Suction Pressure
P3: Gear Pump Discharge CH: Air Bleeds
Pressure Pi: E Mode Control Pressure
PP: Pilot Pump Discharge
Pressure
PLS: Load Pressure
RY9212166HYM0003US0
3-M6 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Configuration Diagram
(1) L/S Regulator (3) Swash Plate (5) Control Pin A (7) Gear Pump
(2) Control Pin B (4) Horsepower Control Spring (6) Horsepower Control Valve
RY9212166HYM0011US0
(2) Function and Structure
[A] Structure
This pump is a quadruple pump configuration
consisting of one cylinder block (1), a piston pump (2)
with a 2-pump function and a twin gear pump (3), all
arranged in-line.
It has a fixed horsepower control function that
controls maximum discharge according to the load and a
load sensing control function (hereafter, L/S), which
supplies the pressure and flow required by the load
within that control range.
The fixed horsepower control (4) is built into the
piston pump and the L/S regulator (5) is attached outside
the piston pump.
(1) Cylinder Block (3) Gear Pump
(2) Piston Pump (Variable (4) Constant Horsepower
Pump) Controller
(5) L/S Regulator
RY9212001HYM0034US0
3-M7 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[B] Operating Principles
(1) Piston (4) Swash Plate (7) Suction Port A : Discharge Side
(2) Retainer Plate (5) Cylinder Block (8) Discharge Port (P1) B : Suction Side
(3) Shoe (6) Valve Plate (9) Discharge Port (P2)
There are 10 pistons (1) built into the cylinder block (5) and coupled to the axle via a spline.
Also, one end of the cylinder block is in contact with a valve plate (6), which has two half-moon shaped ports
(kidney ports); these two kidney ports are connected to suction and discharge ports respectively, so when the cylinder
block rotates, the pistons are connected to the passage on the suction side for an interval of 180 degrees and to the
discharge side for the remaining interval.
The shoes (3) crimped so they can rotate freely against the ball on the end of the piston, and the retainer plate
(2) presses them against the swash-plate (4).
As a result, the shoes are always in contact with the swash-plate as it moves, so as the angle of the swash-plate
changes, that translates into changes in the stroke of the piston and ultimately alters the amount of discharge from
the pump.
As a result of the cylinder block rotation, the side that is pressed into the cylinder block by the piston via the
swash-plate is the discharge path.
At this time the compressed chambers of the cylinder block are connected to the kidney ports on the discharge
side A and the side where the pistons are being withdrawn become the suction path and are connected to the suction
side kidney port.
As a consequence, during the interval of one revolution of the cylinder block, each piston alternately provides
suction at the suction port and then discharge at the discharge port. Thus, smooth pump operation is achieved by
having 10 pistons constantly alternating between suction and discharge.
The ports of the cylinder block are arranged alternately in different diameters; the discharge ports of the valve
plate also have two kinds of ports arranged inside/outside to match, so the flow to be discharged can be split off to
the inner/outer ports and consequently equivalent flow amounts can be obtained simultaneously.
RY9212001HYM0035US0
3-M8 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[C] Horsepower Control
1. Horsepower Control
Horsepower control is a matter of controlling the discharge flow of the piston pump in such a way that the total
consumed horsepower (torque) of the pump does not exceed the specified horsepower (torque) of the engine.
(1) Discharge Pressure P (3) Horsepower Control Spool (5) Horsepower Control Valve (7) Swash Plate
(2) Control Pin A (4) Control Pin B (6) Horsepower Control Spring (8) Reaction Pin
RY9212166HYM0012US0
2. When pressure P is low (when the load is low)
The discharge pressure (1) from the piston pump is
guided to control pin A (2) via oil passages inside the
case. The pressure guided to control pin A produces a
bias pressure equivalent to the pressure P against the
swash-plate, thus pressuring the swash-plate. When
pressure P is low, the horsepower control spool (3) is
positioned at the far left, thus connecting control pin B (4)
to the tank via the horsepower control spool, so there is
no force on control pin B, which results in the maximum
swash-plate tilt angle and discharge flow.
P1/P2: Piston Pump Discharge PPS:Valve Inlet Pressure
Pressure PS: Suction Pressure
P3: Gear Pump Discharge CH: Air Bleeds
Pressure Pi: E Mode Control Pressure
PP: Pilot Pump Discharge
Pressure
PLS: Load Pressure
RY9212166HYM0004US0
3-M9 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
3. When pressure P increases (when the load is great)
(1) Discharge Pressure P (3) Horsepower Control Spool (5) Horsepower Control Valve (9) Reaction Pin
(2) Control Pin A (4) Control Pin B (6) Horsepower Control Spring
When the piston pump discharge pressure P (1) rises due to the load, the horsepower control spool (3) in the
middle of the diagram moves to the right. This connects discharge pressure P to control pin B (4), creating pressure
on control pin B and thus reducing the swash-plate tilt angle and reducing discharge flow. The pump discharge
pressure P is also connected to control pin A (2), but due to the difference in surface area, the swash-plate tilt angle
is reduced. When the swash-plate tilt angle is reduced, the horsepower control spool is moved back to the left by the
horsepower control springs (6), cutting off the connection between discharge pressure P and control pin B, and this
results in a balance of pressure.
Increasing pressure on the E-mode control pressure (Pi) exerts a load on the horsepower control spool (3)
pushing to the left, so compared to when pressure is not applied to the E-mode control pressure (Pi), it allows an
increase in the pump's effective horsepower.
RY9212166HYM0013US0
[D] LS Control
1. LS Control
LS control supplies the pressure and flow needed for
a given load by controlling the pump's discharge
pressure and flow so that pump discharge pressure PPS
= load pressure PLS + spring pressure.
(10) Spring (12) L/S Regulator
(11) Spool
RY9212001HYM0004US0
3-M10 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
2. When the control valve is open wide
If the control valve is opened wide (14) in order to
quickly actuate the actuator, the pressure differential
between the pump discharge pressure P (1) and the load
pressure drops temporarily, moving the spool (11) of the
L/S regulator (12) to the right; this connects control pin B
(4) to the horsepower control valve (5). When this
happens, the horsepower control spool (3) moves to the
left, connecting the control pin B to the tank, thus
increasing the swash-plate tilt angle and increasing
discharge flow. This equalizes the differential pressure
and moves the L/S regulator spool back to the left.
(1) Discharge Pressure P (10) Spring
(2) Control Pin A (11) Spool
(3) Horsepower Control Spool (12) L/S Regulator
(4) Control Pin B (13) Compensator Spool
(5) Horsepower Control Valve (14) Opening Area
(6) Horsepower Control Spring
RY9212166HYM0014US0
3-M11 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
3. When the control valve is slightly open
By contrast, when the control valve is only slightly
open, it produces a large difference in pressure between
the pump discharge pressure P (1) and the load
pressure, so the spool of the L/S regulator moves to the
left and the discharge pressure P and control pin B (4)
are connected. When this happens, it creates pressure
on control pin B, thus reducing the swash-plate tilt angle
and reducing the discharge flow. The pump discharge
pressure is also connected to control pin A (2), but due
to the difference in surface area, the swash-plate tilt
angle is reduced.
(1) Discharge Pressure P (5) Horsepower Control Valve
(2) Control Pin A (6) Horsepower Control Spring
(3) Horsepower Control Spool (11) Spool
(4) Control Pin B (12) L/S Regulator
RY9212166HYM0015US0
[E] Gain Control
There is an orifice (15) in the discharge circuit of the
pilot pump (16) that leads to the spool of the L/S
regulator for differential pressures that arise from
acceleration in engine RPM. This orifice makes it
possible to control pump discharge pressure and flows
so that pump discharge pressure PPS = load pressure
PLS + spring pressure + differential pressure. In other
words, it changes the PPS and PLS differential pressure
control from a constant control to a variable control and
enables the proportional flow control of the engine RPM
by how wide the same control valve is open.
(15) Orifice (16) Gear Pump (Pilot Pump)
RY9212001HYM0041US0
3-M12 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[F] Standby Flow Amount
A standby flow volume is established so that oil is
always flowing in the hydraulic system, even when idling.
Because oil is always flowing to the oil cooler, it is
possible to lower the oil temperature. The front end
(AUX1, swivel, bucket, arm, boom) is in a center closed
circuit, so when all the sections are in neutral, the
operating oil returns to the tank via an unload valve.
(17) Horsepower Control Curve (a) Discharge Pressure
(18) Standby Flow Amount (b) Discharge Flow
RY9212001HYM0042US0
3-M13 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
4. CONTROL VALVE
[1] SPECIFICATIONS
• Standard Specifications
(1) T1 Port (11) Boom Rod (Pa5) (21) P2 Port (31) PAi Port
(2) AUX1 (Pb1) (12) Travel Right Forward (Pb6) (22) P3 Port (32) PLS Port
(3) AUX1 (Pa1) (13) Travel Right Reverse (Pa6) (23) T2 Port (33) AUX2 (Pb10)
(4) Swivel Right (Pb2) (14) Travel Left Forward (Pb7) (24) T3 Port (34) AUX2 (Pa10)
(5) Swivel Left (Pa2) (15) Travel Left Reverse (Pa7) (25) PP1 Port
(6) Bucket Bottom (Pb3) (16) Swing Bottom (Pb8) (26) PP2 Port (a) Main Travel Right Relief
(7) Bucket Rod (Pa3) (17) Swing Rod (Pa8) (27) PP3 Port Valve (aTR)
(8) Arm Bottom (Pb4) (18) Blade Rod (Pb9) (28) PPS1 Port (b) Main Travel Left Relief Valve
(9) Arm Rod (Pa4) (19) Blade Bottom(Pa9) (29) PF1 Port (aTL)
(10) Boom Bottom (Pb5) (20) P1 Port (30) PF2 Port (c) Main P3 Relief Valve (aP3)
(d) Main LS Relief Valve (aLS)
RY9212166HYM0005US0
3-M14 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
• Angle Specification
(1) T1 Port (12) Travel Right Forward (Pb6) (23) T2 Port (33) AUX2 (Pb10)
(2) AUX1 (Pb1) (13) Travel Right Reverse (Pa6) (24) T3 Port (34) AUX2 (Pa10)
(3) AUX1 (Pa1) (14) Travel Left Forward (Pb7) (25) PP1 Port (35) Angle Blade Bottom (Pb11)
(4) Swivel Right (Pb2) (15) Travel Left Reverse (Pa7) (26) PP2 Port (36) Angle Blade Rod (Pa11)
(5) Swivel Left (Pa2) (16) Swing Bottom (Pb8) (27) PP3 Port
(6) Bucket Bottom (Pb3) (17) Swing Rod (Pa8) (28) PPS1 Port (a) Main Travel Right Relief
(7) Bucket Rod (Pa3) (18) Blade Rod (Pb9) (29) PF1 Port Valve (aTR)
(8) Arm Bottom (Pb4) (19) Blade Bottom(Pa9) (30) PF2 Port (b) Main Travel Left Relief Valve
(9) Arm Rod (Pa4) (20) P1 Port (31) PAi Port (aTL)
(10) Boom Bottom (Pb5) (21) P2 Port (32) PLS Port (c) Main P3 Relief Valve (aP3)
(11) Boom Rod (Pa5) (22) P3 Port (d) Main LS Relief Valve (aLS)
RY9212166HYM0006US0
3-M15 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Item Notes
Maker KYB
Model KVSX-14C-72
26.5 MPa
P1 (aTR) 270 kgf/cm2 at 13 L/min (790 cu.in./min, 3.4 USGPM)
3840 psi
26.5 MPa
P2 (aTL) 270 kgf/cm2 at 13 L/min (790 cu.in./min, 3.4 USGPM)
Main relief valve 3840 psi
pressure setting 19.1 MPa
P3 (aP3) 195 kgf/cm2 at 37 L/min (2300 cu.in./min, 9.8 USGPM)
2770 psi
27.4 MPa
LS (aLS) 280 kgf/cm2 at 11 L/min (670 cu.in./min, 2.9 USGPM)
3980 psi
2.55 MPa
Unload LS valve pressure setting (aUN) 26 kgf/cm2 at 23 L/min (1400 cu.in./min, 6.1 USGPM)
370 psi
17.2 MPa
AUX1 (2), (3)
175 kgf/cm2 at 5 L/min (300 cu.in./min, 1.3 USGPM)
AUX2 (33), (34)
2490 psi
31.4 MPa
Bucket (6), (7) 320 kgf/cm2 at 5 L/min (300 cu.in./min, 1.3 USGPM)
4550 psi
31.4 MPa
Arm (8), (9) 320 kgf/cm2 at 5 L/min (300 cu.in./min, 1.3 USGPM)
4550 psi
31.4 MPa
Overload relief valve Boom (10), (11) 320 kgf/cm2 at 5 L/min (300 cu.in./min, 1.3 USGPM)
pressure setting 4550 psi
Blade (18) – Anti-void valve
27.4 MPa
Blade (19) 280 kgf/cm2 at 5 L/min (300 cu.in./min, 1.3 USGPM)
3980 psi
19.0 MPa
Angle blade (35) 190 kgf/cm2 at 5 L/min (300 cu.in./min, 1.3 USGPM)
2800 psi
27.4 MPa
Angle blade (36) 280 kgf/cm2 at 5 L/min (300 cu.in./min, 1.3 USGPM)
3980 psi
RY9212166HYM0016US0
3-M16 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] DIAGRAM OF HYDRAULIC CIRCUIT
Angle Specification
(1) AUX1 (9) Communication Valve (A) Spool Stroke (mm) (a) Boom, Arm, Bucket, AUX1,
(2) Swivel (10) Swing (B) Spool Stroke (mm) Swivel
(3) Bucket (11) Blade (C) Spool Stroke (Main Spool) (b) Travel, AUX2, Swing, Blade
(4) Arm (12) AUX2 (mm) (c) Spool Closed
(5) Boom (13) Angle Blade (D) Pilot Pressure (MPa)
(6) Independent Travel Valve A: Main Spool Pressure
(7) Travel Right Receiver Characteristics
(8) Travel Left B: Independent Travel Valve
C: Communication Valve
RY9212166HYM0007US0
[3] FUNCTION AND STRUCTURE
(1) Independent Travel Circuit
When the travel lever is operated, the hydraulic oil from pumps P1 and P2 passes through the independent travel
valve and the oil from P1 is supplied to the travel right motor while the oil from P2 goes to the travel left motor.
When a front-end operation (AUX1, swivel, boom, arm or bucket) is executed at the same time, oil from the gear
pump P3 is supplied to the front (AUX1, swivel, boom, arm or bucket), so there is little change in speed and the
mini-excavator harnesses a great deal of horsepower for traveling.
RY9212001HYM0054US0
3-M17 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) When Traveling Independently (Operation of Left/Right Forward Travel)
• Angle Specification
(1) Pilot Pressure (8) Swing (15) Boom (a) To Travel Left Section
(2) Pilot Pressure (9) Blade (17) Communication Valve Section (b) To Travel Right Section
(3) Independent Travel Valve (10) PAI Port Differential Pressure (18) Communication Valve (c) To Tank
Spool (11) AUX1 Sub-Spool
(4) Independent Travel Valve (12) Swivel (19) Communication Valve Spool
Section (13) Bucket (20) Tank Circuit
(5) Travel Left section (14) Arm (21) AUX2
(6) Travel Right Section (22) Angle Blade
(7) Main Spool Signal Passage
Section
(To be continued)
3-M18 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(Continued)
When forward travel is initiated, the pilot pressure (1) from the pilot valve presses the main spool for right/left travel
down, as in the circuit diagram.
The pilot pressure (2) from the pilot pump is cut off by the travel left section (5), which raises the pressure inside
the pilot circuit and causes the independent travel spool (3) to be pressed upwards, as in the circuit diagram.
As a result, the oil from the P1 pump is supplied to the travel right section (6) and the oil of the P2 pump goes to
the travel left section (5).
That being the case, the communication valve sub-spool (18) is pressed upwards, as in the diagram, but the pilot
circuit is linked to the hydraulic oil tank, so the communication valve spool (19) does not switch.
RY9212166HYM0017US0
3-M19 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) When Operating Multiple Functions (Travel and Front-End Operation(s))
• Angle Specification
(1) Arm Dump (7) Communication Valve Section (14) Bucket (a) Front (AUX1, Swivel,
(2) Pilot Pressure (8) Blade (15) Swivel Bucket, Arm and Boom)
(3) Communication Valve (9) Swing (16) AUX1 Section
Sub-Spool (10) Travel Left (17) Check Valve
(4) Communication Valve Spool (11) Travel Right (18) AUX2
(5) Outlet Section (12) Boom (19) Angle
(6) Independent Travel Valve (13) Arm
Section
(To be continued)
3-M20 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(Continued)
When travel and front-end operations (AUX1, swivel, boom, arm and bucket) are executed at the same time, the
travel is supplied by oil from pumps P1 and P2, while front operations are supplied by oil from pump P3. Refer to
section [B] "When traveling independently" for information on oil flow for traveling. If a front-end operation (arm dump
(1) operation for example) is initiated while traveling or traveling is initiated while operating the front-end, the pilot
pressure (2) passes through PF1 and is cut off by the arm section, so the pilot pressure passes through the
communication valve sub-spool (3) and presses the communication valve spool (4) upwards, as in the circuit diagram.
Once the communication valve spool is pressed, the oil from pump P3 is cut off by the communication valve spool
and unable to return to the tank, the oil flows to the front-end operation section (arm dump for example).
RY9212166HYM0018US0
(4) Front-End Operation
During front-end operations (AUX1, swivel, boom, arm or bucket) the LS control functions.
RY9212001HYM0057US0
Unload LS Valve
• When spool is in neutral
• When spool is under fine control (unload LS valve control)
(1) Unload LS Spool
(2) Independent Travel Valve Section
(3) Outlet Section
(4) PPS
(5) Notch
(6) Unload LS Valve Spring Chamber
(7) Main Travel Relief Valve
(8) LS Drain Plug
(9) Micro Orifice
(10) PLS Pressure Passage
(11) Tank Line
(12) Main LS Relief Valve
(a) PLS Passage
(b) To Variable Pump
RY9212001HYM0058US0
When main spool is in neutral
• When the main spool is in neutral, no load pressure
PLS is generated, so the PLS pressure does not
work on the unload LS spool (1).
• The oil from pumps P1 and P2 come together inside
the independent travel valve (2) and is guided to the
outlet section (3) via each valve section, but it is
dead-ended by the pump's LS controller so the pump
pressure PPS (4) rises.
• The pump pressure PPS rises until it reaches the
pressure setting of the unload LS valve, at which
point the unload LS spool (1) moves to the right and
the hydraulic oil passes through the notch (5) and
returns to the hydraulic oil tank.
• The discharge flow of the pump when the main spool
is in neutral is controlled by the pressure setting of
the unload LS valve. (Standby Flow Amount)
RY9212032HYM0001US0
3-M21 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
When main spool is under fine control (unload LS
control)
When the main spool moves (fine control), the
hydraulic oil from the pump is channeled to the acutator.
(For example, to A1)
On the other hand, the load pressure on the actuator
passes through the PLS line (a) and operates the unload
LS valve spring chamber (6).
When the main spool is under fine control, the
opening at the spool is small, so the pressure differential
between PPS and PLS becomes great.
The pressure differential increases until it reaches
the pressure setting of the unload LS valve, at which
point the unload LS spool (1) moves to the right, the
opening of the notch between the pump pressure
passage and the tank line is adjusted automatically, thus
maintaining a constant differential pressure between
PPS and PLS.
Consequently, even if the load changes, the
differential pressure between PPS and PLS is
maintained constantly.
RY9212032HYM0002US0
• When spool is operating normally (pump operating)
(1) Unload LS Spool (6) Unload LS Valve Spring (11) Micro Orifice (a) PLS Passage
(5) Notch Chamber
When the main spool moves, the hydraulic oil from the pump is channeled to the acutator. (For example, to A1)
On the other hand, the load pressure on the actuator passes through the PLS line (a) and operates the unload
LS valve spring chamber (6).
When the stroke of the main spool is large, the opening of the spool also becomes large and the pressure
differential between PPS and PLS becomes small. When the differential pressure drops below the pressure setting
of the unload LS valve, the unload LS spool (1) moves to the left, closing off the notch (5). Furthermore, the differential
pressure drops and once it drops to the pump's LS control differential pressure setting (refer to the pump's chapter),
the pump's swash-plate tilt angle becomes large and it causes an increase in the pump's discharge.
In order to prevent pressure from getting pent up in the PLS circuit in cases such as when the operator releases
the control lever, some of the hydraulic oil in the PLS circuit is released via the orifice (11) back to the tank.
RY9212001HYM0059US0
3-M22 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
High Pressure Selection Function
• When operating independently (when an AUX1 Pa port has been added, for example)
(1) Pilot Pressure (6) Shuttle Poppet (11) LS Drain Plug (a) To Variable Pump
(2) Main Spool (7) PLS Pressure Passage (12) Micro Orifice (b) From Unload LS Valve to
(3) Load Check Poppet (8) Independent Travel Valve (13) Tank Line Tank Line
(4) Control Spool Section (14) Air Bleed Micro-Orifice (c) Pump Passage
(5) LS Pressure Inlet Orifice (9) Main Travel Relief Valve
(10) PPS Pressure
When the pilot pressure (1) operates the Pa port, it moves the main spool (2) to the left and the pressurized oil
from the pump passes through the Pc notch in the main spool and then the pressurized oil flows through the C notch
of the compensator spool (pressure compensator valve), the right side load check (3) and the LSC notch and then
from port A to the actuator.
Part of the oil that passed through the Pc notch goes through the LS pressure inlet orifice (5) of the compensator
spool (4), pushing up the shuttle poppet (6), passing through the PLS pressure passage (7) and to the variable pump
as the PLS pressure.
RY9212001HYM0060US0
When operating multiple functions (when using AUX1 and swiveling, for example)
(1) High Pressure Selection (2) Compensator Spool (A) AUX1 (B) Swivel
Location
When AUX1 (A) and swivel (B) are operated at the same time, if the pressure load of swiveling is higher than that
of AUX1, the load pressure of swiveling is selected as the PLS pressure.
RY9212001HYM0005US0
3-M23 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(5) Compensator Spool (Pressure Compensator Valve)
When operating independently
The hydraulic oil passes through the pump pressure
passage (1), the PC passage (2) and the compensator
spool (3) and is guided to the top of the compensator
spool as the PLS pressure (4). When operating
independently, the PC passage pressure acts as the
load pressure, so the compensator spool is adjusted to a
position that matches this pressure.
When operating multiple functions
• Sections with a heavy load pressure
The load pressure of such a section is selected as
the PLS pressure (4), so it operates the same way as
with independent operation.
• Sections with a light load pressure
The load pressure of a section with a heavy load
pressure is selected as the PLS pressure (4) and the
swash-plate is controlled by this PLS pressure (4),
so an almost identical pressure is exerted on each
section of PC passage pressure.
The difference between the PC passage pressure
and the load pressure of a section with a low load
pressure is generated by the orifice built into the
compensator spool (3), the compensator spool (3)
moves to the position where the differential pressure
is balanced (when the compensator spool (3) is
down, the total area of the compensator spool's
orifice is small, so the difference between PC
passage pressure and load pressure becomes
great).
As a result, even if the load pressures of two sections
are different, the compensator spool (3) works to
equalize pressure so an almost identical pressure
exists in the PC passage, thus changes in load are
not received and a flow is obtained simply by the size
of the opening in the spool.
(1) Pump Pressure Passage (3) Compensator Spool
(2) PC Passage (4) PLS Pressure
RY9212001HYM0006US0
3-M24 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
5. SWIVEL MOTOR
[1] SPECIFICATIONS
(1) Port A (3) Make-Up Port (5) Pilot Port (Parking Brake) (6) Relief Valve
(2) Port B (4) Drain Port
RY9212032HYM0012US0
Item Notes
Maker Kubota Seiki
Model SM29G2
29.271 cc/rev
Motor Displacement
1.786 cu.in./rev
Reduction Ratio 21.263
622.4 cc/rev
Total Displacement
37.98 cu.in./rev
41.0 L/min
Max Flow
2500 cu.in./min
Theoretical RPM 65.9 rpm
20.6 MPa at 41 L/min
Relief Valve Brake Pressure 210 kgf/cm2 (2500 cu.in./min,
2990 psi 10.8 USGPM)
2040 N·m
Mechanical Brake Torque 208.0 kgf·m
2958 lbf·ft
1.5 MPa ≥
Parking Brake Release Pressure 15 kgf/cm2 ≥
220 psi ≥
RY9212166HYM0032US0
3-M25 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] COMPONENTS
(A) Plug Parts (1) (B) Plug Parts (2) (C) Drain Parts
3-M26 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(2),(20),
(1) Motor ASSY (with valves) 1 (46) Nut 2
(47) to (57)
(2) Motor ASSY 1 (3) to (19),(58) (47) Cover (motor) 1
(3) Ball bearing 1 (48) Plug (R1/4) 2
(4) Shaft 1 (49) Ball bearing 1
(5) Thrust plate 1 (50) Plate (valve) 1
(6) Cylinder block (swivel) 1 (51) Parallel pin 1
(7) Metal washer (spring) 1 (52) Parallel pin 2
(8) Spring CY 1 (53) Parallel pin 2
(9) Metal washer (spring) 1 (54) O-Ring 1
(10) Internal circlip 1 (55) O-Ring 2
(11) Pin 1 (56) Hex socket bolt 7
(12) Piston ASSY 9 (57) O-Ring 1
(13) Plate (retainer) 1 (58) O-Ring 2
(14) Holder (retainer) 1 (59) Gear case ASSY (swivel) 1 (60) to (82)
(15) Plate (friction) 1 (60) Gear case 1
(16) Piston (brake) 1 (61) Tapered roller bearing 1
(17) O-Ring 1 (62) Plate (valve) 1
(18) O-Ring 1 (63) Plate (pinion) 1
(19) Spring (NB) 12 (64) Plate (pinion 2) 1
(20) Valve ASSY (swivel) 1 (21) to (46) (65) Shaft (pinion) 1
(21) Housing (motor and valves) 1 (66) Oil Seal 1
(22) Poppet 2 (67) Tapered roller bearing 1
(23) Compression spring 2 (68) Spacer 2
(24) Plug 2 (69) Holder (2) 1
(25) O-Ring 2 (70) Collar (2) 4
(26) Piston (shockless) 1 (71) Needle bearing 4
(27) Plug (G1/2) 2 (72) Gear (planetary 2) 4
(28) O-Ring 2 (73) Plate (thrust 2) 4
(29) Valve ASSY (relief) 2 (30) to (46) (74) External circlip 4
(30) Housing (relief) 2 (75) Gear (sun) 1
(31) O-Ring 2 (76) External circlip 1
(32) O-Ring 2 (77) Holder (1) 1
(33) Ring (backup) 2 (78) Collar (1) 3
(34) Plug (relief) 2 (79) Needle bearing 3
(35) O-Ring 2 (80) Gear (planetary 1) 3
(36) Guide (spring) 2 (81) Plate (thrust) 1
(37) O-Ring 2 (82) Gear (drive) 1
(38) Ring (backup) 2 (83) Hex socket bolt 2
(39) Compression spring 2 (84) Filter 1
(40) Ring (spring seat) 2 (85) O-Ring 1
(41) Poppet 2 (86) Plug (G1/2) 1
(42) Ring (Poppet seat) 2 (87) O-Ring 1
(43) O-Ring 2 (88) Plug (G1/4) 1
(44) Backup ring 4 (89) O-Ring 1
(45) Set screw 2
RY9212001HYM0065US0
3-M27 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[3] FUNCTION AND STRUCTURE
(1) Operating Principles
The pressurized oil from port A (1) goes through
valve plate (3), enters piston (5) inside cylinder block (4)
and presses against the swash-plate (6). The pistons
receive the counterforce from the swash-plate, part of
which becomes rotational force, and the block rotates
due to the sum total of the rotational forces exerted by
the pistons that the hydraulic oil entered. The cylinder
block and the shaft (7) are linked via a spline, so rotation
is transferred to the shaft.
When in reverse, hydraulic oil flows in via port B (2)
and is discharged via port A.
(1) Port A (5) Piston
(2) Port B (6) Swash Plate
(3) Valve Plate (7) Shaft
(4) Cylinder Block
RY9212001HYM0066US0
(2) Make Up Circuit
If the swivel is decelerated with the pressurized oil
supplied via port A, the motor rotates due to the inertia of
the swiveling equipment, and the motor drives the pump.
As a result, the load shifts to the port A side.
In order to prevent this, the oil on the return side
passes through the poppet (1) in the make up circuit and
is supplied to the port A side.
(1) Poppet (a) To Motor MA Circuit
RY9212001HYM0067US0
3-M28 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Shockless Valves
• At start up and shutdown, the oil that has flowed into
port A passes through the orifice (2) of the relief
valve (1) and into chamber A (3). At such time, the
Pa pressure > Pb pressure, so the relief valve
operates at a pressure lower than its pressure
setting. (Primary relief pressure)
• When piston (4) reaches the left side as in the
diagram, the pressure in chamber A rises, so Pa=Pb.
For this reason, the relief valve operates at the
pressure setting. (Secondary relief pressure)
• Because of this, the system can suppress dramatic
changes in pressure and can mitigate the shock of
starting up and stopping the equipment.
(1) Relief Valve (a) From Port A
(2) Orifice
(3) Chamber A
(4) Piston
RY9212001HYM0068US0
3-M29 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(4) Parking Brake
1. When the parking brake is operated
When the unload lever is raised, the oil in the brake
piston chamber (1) passes through the unload valve and
returns to the hydraulic oil tank, thus allowing the force
of the spring (2) to press the brake piston (3) downwards.
As a result, the friction plate (4) is squeezed between
the brake piston and the case (5), and the friction
prevents any rotation.
The friction plate and the cylinder block (6), the
cylinder block and the shaft (7) are coupled via a spline,
so the motor (shaft) will not rotate.
2. When the parking brake is released
When the unload lever is lowered, the oil from the
pilot pump passes through the unload valve and flows
into the brake piston chamber, overpowering the spring
and pressing the brake piston upwards, as in the
diagram.
By doing so, the friction of the friction plate is
released and the motor (shaft) rotates.
(1) Brake Piston Chamber (5) Case
(2) Spring (6) Cylinder Block
(3) Brake Piston (7) Shaft
(4) Friction Plate
RY9212001HYM0069US0
3-M30 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
6. TRAVEL MOTOR
[1] SPECIFICATIONS
(1) Counterbalance Valve/ (2) Travel 2-Speed/Travel (4) Port P2 (G1/2) (6) Drain Port (G1/4)
Anticavitation Valve Automatic Reduction (5) Port PS (G1/4) (7) Oil Inspection Port
(3) Port P1 (G1/2) (2-Speed Travel Switch) (8) Oil Fill Drain Port
RY9212032HYM0013US0
Item
Maker KYB
Model MAG-33VP-650F-4
1674 cc / 943 rev
Total displacement 1-speed/2-speed
102.2 cu.in. / 57.5 rev
28.4 cc / 16.0 rev
Motor displacement 1-speed/2-speed
1.73 cu.in. / 0.98 rev
Reduction Ratio 1 : 58.943
26.5 MPa
Max Pressure 270 kgf/cm2
3840 psi
Rated Flow 56.1 L/min (3420 cu.in./min, 14.8 USGPM)
33.5 / 59.5 rpm
Theoretical RPM 1-speed/2-speed
at 56.1 L/min (3420 cu.in./min, 14.8 USGPM)
7060 / 3980 N·m
719.9 / 405.8 kgf·m
Theoretical Torque Output 1-speed/2-speed
5207 / 2935 lbf·ft
at 26.5 MPa (270 kgf/cm2 , 3840 psi)
4456 N·m
Parking Brake Control Torque 454.4 kgf·m
3287 lbf·ft
1.2 MPa
Parking Brake Release Pressure 12.2 kgf/cm2
174 psi
3.92 MPa
Auto 2-speed Control Pilot Pressure (PS) 40.0 kgf/cm2
569 psi
20.0 MPa
2nd speed→
202.7 kgf/cm2
1st speed
Motor Displacement Control Pressure 2883 psi
when PS=3.92 MPa, 40 kgf/cm2, 570 psi 20.6 MPa
1st speed→
208.8 kgf/cm2
2nd speed
2970 psi
RY9212166HYM0019US0
3-M31 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] COMPONENTS
(A) Anticavitation Valve
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Decelerator ASSY 1 (1) to (28) (12) Inner race 4
(2) Flange holder 1 (13) Thrust washer 4
(3) Floating Seal 2 (14) Thrust plate 1
(4) Angular bearing 1 (15) Screw 4
(5) Ring nut 1 (16) Sun gear 1
JIS B 2804, 42
(6) Plug 2 (17) Thrust washer 3
SHAFT
(7) Housing 1 (18) Holder 1
(8) Steel ball 99 JIS B 1501, 1/4 (19) Planetary gear A 3
(9) Plug 2 PT1/8 (20) Cage and roller 3
(10) Planetary gear B 4 (21) Inner race 3
(11) Needle bearing 4 (22) Drive gear 1
3-M32 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(23) Thrust plate 1 (62) Spool ASSY 1 (63), (64)
(24) Cover 1 (63) Spool A 1
JIS B 2401, 1B,
(25) O-Ring 1 (64) Spool C 1
G190
(26) Wire 1 (65) Spring 1
(27) Plug 3 (66) Plug 1 PF3/8
(28) O-Ring 3 JIS B 2401, 1B, P14 (67) O-Ring 2 JIS B 2401, 1B, P14
(29) Shaft 1 (68) Plug 3 NPTF1/16
(30) Ball bearing 1 (69) Plug 1
(31) Oil Seal 1 (70) Orifice 6 M5x0.8x5L 0.5
JIS B 1176,
(32) Swash-plate 1 (71) Socket head bolt 6
M12x25L
(33) Steel ball 2 (72) Pin 4
(34) Cylinder block 1 (73) Valve ASSY 1 (74) to (81)
(35) Spring seat 1 (74) Valve body 1
(36) Spring 1 (75) Spool 1
(37) Washer 1 (76) Spring 2
JIS B 2804, 37
(38) Snap ring 1 (77) Spring seat 2
HOLE
(39) Pin 3 2.5x15.8L (78) Plug 2 PF3/8
(40) Retainer holder 1 (79) O-Ring 2 JIS B 2401, 1B, P14
(41) Retainer plate 1 (80) O-Ring 3 JIS B 2401, 1B, P12
(42) Piston ASSY 9 (81) Socket head bolt 3 JIS B 1176, M8x30L
(43) Piston 2 (82) Nameplate 1
(44) Spring 2 (83) Drive screw 2 1.85x4.8L
(45) Valve plate 1 (84) Shipping plug 2 PT1/2
(46) Pin 1 4x12L (85) Shipping plug 1 9/16UNF
(47) Ball bearing 1 (86) Plug 1 PT1/8
(48) O-Ring 1 AS568-25B, 1A (87) O-Ring 2 JIS B 2401, 1B, P8
(49) O-Ring 4 JIS B 2401, 1B, P7 (88) Plug 2
(50) Baseplate 1 (89) Plug 2
(51) Plunger ASSY 1 (52) to (56) (90) Brake piston 1
(52) Spool 1 (91) Disc 1
(53) Check valve 2 (92) Spring 8
(54) Spring 2 (93) Spring 4
(55) Plug 2 (94) O-Ring 1
(56) O-Ring 2 JIS B 2401, 1B, P10 (95) O-Ring 1
(57) Spring seat 2 (96) Orifice 2 M5x0.8x5L 0.5
(58) Spring 2 (97) Spring seat 1
(59) Cap 2 (98) Plug 2
(60) O-Ring 2 JIS B 2401, 1B, P29 (99) O-Ring 2 JIS B 2401, 1B, P14
(61) Orifice 2 M5x0.8x5L 0.5
RY9212001HYM0082US0
3-M33 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[3] FUNCTION AND STRUCTURE
(1) Operating Principles
• Nine pistons are built into the cylinder block, and the
end section of the block is in contact with a valve
plate, which has two half-moon shaped ports (port B
and port C for switching between high and low
pressure).
• If high-pressure oil is guided to port B, the
pressurized oil passes through port B and presses
on the swash-plate.
• The pistons receive the counterforce from the
swash-plate, part of which is converted into
rotational force, and the block rotates due to the sum
total of the rotational forces exerted by pistons that
the hydraulic oil entered.
• The cylinder block and the shaft are linked via a
spline, so the rotation is transferred to the shaft.
(1) Cylinder Block B : Port B
(2) Piston C : Port C
(3) Valve Plate
(4) Swash Plate
(5) Shaft
RY9212001HYM0002US0
(2) Counter-Balance Valve
When in neutral
Role of the counter-balance valve
1. Stops the motor (b).
2. Prevents overrun.
When control valve (a) is in neutral, no pressure is
generated at either port P1 or P2, so ports M1 and M2
are blocked by plunger (1), check valve L (2) and check
valve R (3), so the motor does not rotate.
(1) Plunger (a) Control Valve
(2) Check Valve L (b) Motor
(3) Check Valve R
RY9212001HYM0083US0
3-M34 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
If pressurized oil flows to P1
The pressurized oil that passed through P1 flows
through check valve L (2) to the motor (b) via the M1
port, thus turning the motor.
The oil returning from the motor flows to the
counter-balance valve from port M2, but it is blocked by
the check valve R (3), so the pump discharge pressure
rises. Pressurized oil passes through orifice L (4) and
acts on the left side of plunger (1), moving the plunger to
the right.
Oil returning from port M2 passes through the
plunger notch (5) and while generating back pressure on
port M2, returns to the tank via port P2 and the control
valve (a).
As the pump's discharge pressure rises further, the
plunger moves further to the right, enlarging the opening
of the orifice at the plunger notch, thus reducing the back
pressure.
In this way the degree of opening of the plunger
notch orifice automatically adjusts the return passage
area so that the motor rotates at a speed that matches
the pressure on the port P1 side.
(1) Plunger (a) Control Valve
(2) Check Valve L (b) Motor
(3) Check Valve R
(4) Orifice L
(5) Plunger Notch Section
RY9212001HYM0084US0
Brake operation
When the control valve (a) returns to neutral, it cuts
off the supply of pressurized oil from the pump, and the
pressures at ports P1 and P2 equalize, so spring R (3)
works to return the plunger (1) to its neutral position.
(moves to the left)
When the plunger moves to the left, the size of the
orifice in the plunger notch (5) becomes smaller. Also,
the motor (b) tries to turn due to inertia, which causes the
pressure on the port M2 side to rise. When the plunger
moves to the left, the oil in the left pressure chamber (2)
escapes to the port P1side, but due to the constricting
effect of orifice L (4), the speed with which the plunger
moves to the left is limited.
By controlling the speed of the plunger, the motor is
stopped without generating cavitation while also
absorbing the shock pressure from the inertia of the
motor.
(1) Plunger (a) Control Valve
(2) Left Pressure Chamber (b) Motor
(3) Spring R
(4) Orifice L
(5) Plunger Notch Section
RY9212001HYM0085US0
3-M35 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Anti-Cavitation Valve
The anti-cavitation valve functions in conjunction
with the counterbalance valve.
The figure at left shows the counterbalance valve in
neutral.
(1) Plunger (7) Oil Passage A
(2) Oil Passage C (8) Orifice B
(3) Spool (9) Orifice C
(4) Oil Passage M2
(5) Oil Passage M1 (b) Motor
(6) Oil Passage B
RY9212001HYM0086US0
Motor stopped → start
If pressurized oil flows to port P1, plunger (1) moves
to the right and oil flows to the motor (b) via passage
M1(5), passes through passage M2 (4) and is expelled
from port P2.
Although pressurized oil also flows to oil passage A
(7), since it is cut off by the spool (3), pressurized oil
does not flow to oil passage C (2).
Under steady motor rotation
Although pressurized oil also flows to oil passage A
(7), since it is cut off by the spool, the pressurized oil
does not flow to oil passage C.
(1) Plunger (b) Motor
(2) Oil Passage C
(3) Spool (A) [High Pressure] Inflow
(4) Oil Passage M2 (B) [Low Pressure] Discharge
(5) Oil Passage M1
(6) Oil Passage B
(7) Oil Passage A
RY9212001HYM0087US0
3-M36 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
When going from a steady motor speed →
deceleration
When decelerating, the motor (b) continues to turn
due to its inertia.
As long as the counterbalance valve is open (the
plunger (1) is moved to the right), the motor's return oil
passes through oil passage M2 (4) and is expelled from
port P2. At that time, there is not enough oil supplied
under pressure from port P1, resulting in cavitation.
On the other hand, the pressure in oil passage M2
rises due to inertia, moving the spool (3) to the left, and
during the interval until the plunger moves to the left, it
passes through oil passage M2 → orifice C (9) → oil
passage C (2) → spool (3) → oil passage A (7) → P1 →
oil passage M1 (5) and resupplies the motor, thus
reducing cavitation. (Anticavitation function)
The mechanism is structured so the spool (3)
switches instantaneously and the anti-cavitation function
starts operating. (High-pressure selection method)
(1) Plunger (b) Motor
(2) Oil Passage C
(3) Spool (A) Inflow
(4) Oil Passage M2 (B) Discharge
(5) Oil Passage M1
(7) Oil Passage A
(9) Orifice C
RY9212001HYM0088US0
When motor decelerating → stop
The anticavitation function moves the plunger (1)
further to the left until oil passage A (2) and port P1 are
cut off.
(1) Plunger (b) Motor
(2) Oil Passage A (c) Position that Cuts Oil
(3) Spool Passage A Off from P1
(4) Oil Passage M2
(5) Oil Passage M1 (A) Inflow
(B) Discharge
RY9212001HYM0089US0
3-M37 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(4) Auto-Decelerator Function
When under low load
(1) PS Port (3) Motor Load Pressure (5) Pilot Pressure Area (a) Motor Load Pressure
(2) Spool Chamber (6) 2-Speed Switch Piston (b) Low Pressure
(4) Motor Load Pressure Area (c) High Pressure
When the mini-excavator is traveling in 2nd speed, if the travel load becomes great, this function gives priority to
power for traveling, automatically decelerating to 1st speed (low-speed). When the load is low, it operates in the 2nd
speed (high-speed).
When the green button on top of the dozer lever is pressed, it actuates the solenoid of the unload valve, thus
guiding oil from the pilot pump to the PS port (1). When pressure oil flows to the PS port, it moves the spool (2) to the
right.
On one hand, the motor load pressure (a) is applied in the motor load chamber (3) and moves the spool to the
left. When the load is low, the force applied in the motor load pressure chamber is slight and the motor load pressure
area (4) is also small, due to the pilot pressure area (5), so the spool is pushed to the right and the pressurized oil
from P1 is supplied to the 2-speed switch piston (6) on the P1 side.
RY9212001HYM0090US0
3-M38 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
When the load is heavy
(1) PS Port
(2) Spool
(3) 2-Speed Switch Piston
(a) Motor Load Pressure
(b) Case Drain
(c) Low Pressure
The motor load pressure (a) rises, so it overpowers the oil pressure from the PS port (1) and moves the spool (2)
to the left, and switches to 1st speed (low speed).
When traveling in 1st speed, pressurized oil is not applied to the PS port, so it acts the same as when under a
heavy load.
RY9212001HYM0091US0
(5) Parking Brake
The parking brake is a negative brake composed of
a rotating disc (friction material) (4), a brake piston (3)
and a spring (1). When the travel motor is stopped (the
travel lever in neutral), the parking brake takes effect.
The cylinder block (5) and the disc are linked via a
spline (6) and a friction material is applied to both sides
of the disc. The disc is spring-loaded and friction is
generated between the flange holder and the brake
piston, and this limits the force with which the motor can
turn, allowing it to function as a parking brake.
When pressurized oil is guided into the brake piston
chamber (2), it generates an amount of thrust that
matches the area of the brake piston that receives the
pressure and overcomes the spring, thus moving the
brake piston. The disk rotates freely between the flange
holder and the brake piston, eliminating the parking
brake function.
(1) Spring (4) Disc (Friction Material)
(2) Brake Piston Chamber (5) Cylinder Block
(3) Brake Piston (6) Spline
RY9212001HYM0092US0
3-M39 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(6) Decelerator
• The drive gear meshes with the 1st stage planetary
gear while the 2nd stage sun gear meshes with the
2nd stage planetary gear.
• The 2nd stage planetary carrier is fixed to the body
of the decelerator.
• Planetary gears and mesh with ring gear (the
housing).
• The drive force from the piston motor is transmitted
to the drive gear, which is decelerated by each of the
gears.
• The decelerated drive force is transmitted to the ring
gears via the 2nd stage planetary gear of the 2nd
stage planetary carrier, which is fixed to the final
stage of the decelerator. (The drive force from the
1st stage planetary gear is also transmitted.)
• However, the input rotation is opposite the output
rotation.
(1) Drive Gear (5) 2nd Stage Planetary Gear
(2) 1st Stage Planetary Gear (6) 2nd Stage Planetary Carrier
(3) 1st Stage Planetary Carrier (7) Ring Gear (Housing)
(4) 2nd Stage Sun Gear
RY9212001HYM0003US0
3-M40 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
7. HYDRAULIC CYLINDER
[1] BOOM CYLINDER
(1) Specifications
Maker KYB
Tube outer diameter 117 mm (4.61 in.)
Tube inner diameter 95 mm (3.7 in.)
Rod diameter 55 mm (2.2 in.)
Stroke 690 mm (27.2 in.)
Max compressed length 1,074 mm (42.28 in)
RY9212166HYM0020US0
(2) Components
(a) G1/2 (O-Ring Type) (b) Cushion Stroke 40 mm
(1.6 in)
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Cylinder tube ASSY 1 (13) Cushion seal 2
(2) Piston rod ASSY 1 (14) Collar 1
(3) Cylinder head 1 (15) Backup ring 1
(4) Bushing 1 (16) Cushion bearing 1
(5) Snap ring 1 (17) Piston 1
(6) Buffer ring 1 (18) Sealing ASSY 1
(7) U-ring 1 (19) Slide ring 2
(8) Wiper ring 1 (20) Set screw 1 B1177 M10x10
(9) O-Ring 2 B2401 1B G 90 (21) Steel ball 1
(10) Backup ring 1 (22) Pin bushing 2
(11) O-Ring 1 B2401 1A G 95 (23) Grease nipple 1 B1575 B-PT1/8
(12) Holder 1
RY9212166HYM0038US0
3-M41 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Function and Structure
Cushion Function
A cushion is utilized on the lift end of the boom (side of cylinder that extends) to prevent dirt from spilling.
• Cushion function on the lift end of the boom
(a) Flow via a Slit (b) Flow from Indentation
The discharge pressurized oil is automatically reduced on the lift end of the boom, slowing the operation of the
cylinder and cushioning the shock on the lift end of the boom. An indentation and a split in the cushion bearing are
provided as a means to reduce the pressure.
RY9212001HYM0096US0
3-M42 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] ARM CYLINDER
(1) Specifications
Maker KYB
Tube outer diameter 105 mm (4.13 in)
Tube inner diameter 85 mm (3.3 in.)
Rod diameter 55 mm (2.2 in.)
Stroke 691 mm (27.2 in.)
Max compressed length 1,105 mm (43.5 in.)
RY9212166HYM0021US0
(2) Components
(a) G1/2 (O-Ring Type) (b) Cushion Stroke 35 mm
(1.4 in.)
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Cylinder tube ASSY 1 (15) Collar 1
(2) Piston rod ASSY 1 (16) Backup ring 1
(3) Cylinder head 1 (17) Cushion bearing 1
(4) Bushing 1 (18) Piston 1
(5) Snap ring 1 (19) Sealing ASSY 1
(6) Buffer ring 1 (20) Slide ring 2
(7) U-ring 1 (21) Set screw 1 B1177 M10x10
(8) Wiper ring 1 (22) Steel ball 1
(9) O-Ring 2 B2401 1B G 80 (23) Cushion bearing 1
(10) Backup ring 1 (24) Cushion seal 1
(11) O-Ring 1 B2401 1A G 85 (25) Snap ring 1
(12) Holder 1 (26) Stopper 2
(13) Cushion seal 1 (27) Pin bushing 2
(14) Spacer 1
RY9212032HYM0017US0
3-M43 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Function and Structure
Cushion Function
A cushion is utilized on the rake end of the arm (side of cylinder that extends) to prevent dirt from spilling.
• Cushion function on the rake end of the arm
(a) Flow via a Slit (b) Flow from Indentation
The discharge pressurized oil is automatically reduced on the rake end of the arm, slowing the operation of the
cylinder and cushioning the shock on the rake end of the arm. An indentation and a split in the cushion bearing are
provided as a means to reduce the pressure.
RY9212001HYM0100US0
• Cushion function on dumping end of arm
(1) Port (3) Cushion Plunger A : Before Cushion Enters
(2) Cushion Chamber (4) Piston B : After Cushion Enters
RY9212001HYM0101US0
3-M44 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[3] BUCKET CYLINDER
(1) Specifications
Maker KYB
Tube outer diameter 91 mm (3.6 in.)
Tube inner diameter 75 mm (3.0 in.)
Rod diameter 45 mm (1.8 in.)
Stroke 589 mm (23.2 in.)
Max compressed length 896 mm (35.3 in.)
RY9212166HYM0022US0
(2) Components
(a) G1/2 (O-Ring Type)
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Cylinder tube ASSY 1 (14) Slide ring 2
(2) Piston rod ASSY 1 (15) Set screw 1
(3) Cylinder head 1 (16) Steel ball 1
(4) Bushing 1 (17) Pin bushing 1
(5) Snap ring 1 (18) Pin bushing 1
(6) Buffer ring 1 (19) Pipe ASSY 1
(7) U-ring 1 (20) Pipe ASSY 1
(8) Wiper ring 1 (21) Plug 2
(9) O-Ring 1 B2401 1B G 70 (22) O-Ring 4 B2401 1B P 22A
(10) Backup ring 1 (23) Bolt ASSY 2
(11) O-Ring 1 B2401 1A G 75 (24) Pipe holder 2
(12) Piston 1 (25) Grease nipple 1 B1575 B-PT1/8
(13) Seal ring ASSY 1
RY9212001HYM0104US0
3-M45 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[4] SWING CYLINDER
(1) Specifications
Model KX057-4 U55-4
Maker Kubota Seiki
Tube outer diameter 107 mm (4.21 in.)
Tube inner diameter 90 mm (3.5 in.)
Rod diameter 50 mm (2.0 in.)
Stroke 486 mm (19.1 in.)
Max compressed length 930 mm (36.7 in.) 790 mm (31.1 in.)
RY9212166HYM0023US0
(2) Components
(a) G1/4
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Cylinder tube (W) 1 (8) Gasket (dual) 1
(2) Rod (swing) 1 (9) O-Ring 1
(3) Bushing 2 (10) Piston 1
(4) Cylinder head 1 (11) Seal (piston) 1
(5) DU bushing 1 (12) Bushing 2
(6) Gasket 1 (13) Nut (SSN36) 1 M36×3
(7) Scraper 1
RY9212001HYM0106US0
3-M46 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[5] BLADE CYLINDER
(1) Specifications
Maker Koretsune Seiko
Tube outer diameter 131 mm (5.16 in.)
Tube inner diameter 110 mm (4.33 in.)
Rod diameter 60 mm (2.4 in.)
Stroke 170 mm (6.69 in.)
Max compressed length 515 mm (20.3 in.)
RY9212166HYM0024US0
(2) Components
(a) G3/8 (b) G1/2
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Tube ASSY 1 (12) Backup ring 1
(2) Rod ASSY 1 (13) Seal 1
(3) Bearing 2 (14) O-Ring 1
(4) Piston 1 (15) Backup ring 1
(5) Nut 1 (16) O-Ring 1
(6) Seal ASSY 1 (17) Grease nipple 1
(7) Ring 2 (18) Grease nipple 1
(8) Head 1 (19) Pipe ASSY 1
(9) Bushing 1 (20) Clamp 1
(10) Circlip 1 (21) Bolt 1
(11) Seal 1
RY9212001HYM0108US0
3-M47 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[6] ANGLE CYLINDER
(1) Specifications
Maker Koretsune Seiko
Tube outer diameter 78 mm (3.1 in.)
Tube inner diameter 65 mm (2.6 in.)
Rod diameter 35 mm (1.4 in.)
Stroke 412 ± 1.5 mm (16.2 ± 0.06 in.)
Max compressed length 515 mm (20.3 in.)
RY9212166HYM0025US0
(2) Components
(a) G3/8 (O-Ring Type)
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Tube ASSY 1 (9) Snap ring 1
(2) Rod ASSY 1 (10) Seal 1
(3) Piston 1 (11) Backup ring 1
(4) Lock nut 1 (12) Seal 1
(5) Head 1 (13) O-Ring 1
(6) Seal ASSY 1 (14) Backup ring 1
(7) Ring 2 (15) O-Ring 1
(8) Bearing 1 (16) Bearing 2
RY9212050HYM0017US0
3-M48 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
8. PILOT VALVE
[1] PILOT VALVE (BOOM, ARM, BUCKET, SWIVEL)
(1) Specifications
1. Pilot Valve Left
(1) Port P (7) Independent Operation (a) Secondary Pressure (e) Pushrod Stroke (mm)
(2) Port 1 (Swivel Left) Torque (Port 1, 3) (kgf/cm2) (f) Operating Angle (deg)
(3) Port 2 (Arm Dump) (8) Independent Operation (b) Secondary Pressure (MPa)
(4) Port 3 (Swivel Right) Torque (Port 2) (c) Operating Torque (N·m)
(5) Port 4 (Arm Rake) (9) Independent Operation (d) Operating Torque (kgf·cm)
(6) Port T Torque (Port 4)
(10) Secondary Pressure
Maker KPM (Kawasaki Precision Machinery)
Model PV48M2197 (LH)
Secondary pressure Noted separately
RY9212166HYM0026US0
3-M49 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
2. Pilot Valve Right
(1) Port P (7) Independent Operation (a) Secondary Pressure (e) Pushrod Stroke (mm)
(2) Port 1 (Bucket Rake) Torque (Port 1) (kgf/cm2) (f) Operating Angle (deg)
(3) Port 2 (Lower Boom) (8) Independent Operation (b) Secondary Pressure (MPa)
(4) Port 3 (Dump Bucket) Torque (Port 2) (c) Operating Torque (N·m)
(5) Port 4 (Lift Boom) (9) Independent Operation (d) Operating Torque (kgf·cm)
(6) Port T Torque (Port 4)
(10) Secondary Pressure
Maker KPM (Kawasaki Precision Machinery)
Model PV48M2198 (RH)
Secondary pressure Noted separately
RY9212166HYM0027US0
3-M50 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Components
Pilot valves left and right
No. Name of part Q'ty Notes
(1) Casing 1
(2) Plate 1
(3) Spool 4
(4) Plug 4
(5) Pushrod 4
(6) Seal 4
(7) O-Ring 4
(8) Spring seat 4
(9) Washer 2 4
(10) Spring 1 For port 1
(11) Spring 1 For port 2
(12) Spring 1 For port 3
(13) Spring 1 For port 4
(14) Spring 4
(15) Joint 1
(16) Round plate 1
(17) Adjusting nut 1
(18) Bellows 1
(a) Port 2, 4 (b) Port 1, 3
RY9212001HYM0111US0
3-M51 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Function and Structure
[A] Function
The pilot valve is the valve that controls the direction and volume of the stroke of the control valve, and lowers the
primary pressure from the unload valve to a secondary pressure only as much as is necessary to move the control
valve spool.
RY9212001HYM0001US0
[B] Operation
1. When the control lever is in neutral
The force of the secondary pressure setting spring
(14) does not press on the spool (3). As a result, the
spool is held in a neutral position by return spring (11) or
(13). At such time, the output port (control valve port) (a)
and port T (b) are connected.
(3) Spool (a) Output Port
(11) Return Spring (b) Port T
(13) Return Spring
(14) Secondary Pressure Setting
Spring
RY9212001HYM0112US0
2. When the control lever has been actuated
When the control lever is actuated, the pushrod (5)
presses down on the spool (3) via the spring seat (8) and
the secondary pressure setting spring (14). When doing
so, port P (b) and the output port (a) are connected, so
the oil from the pilot pump flows through the output port
to the control valve.
The pressure at the output port rises until it is
equivalent to the force of the secondary pressure setting
spring, thus balancing the hydraulic pressure on the
spool with the tension of the secondary pressure setting
spring and maintaining a fixed output port pressure.
(3) Spool (a) Output Port
(5) Pushrod (b) Port P
(8) Spring Seat
(14) Secondary Pressure Setting
Spring
RY9212001HYM0113US0
3-M52 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] PILOT VALVE (TRAVEL)
(1) Specifications
(1) Port P (4) Port 2 (7) Operating Torque (a) Secondary Pressure (MPa)
(2) Port T (5) Port 3 (8) Secondary Pressure (b) Operating Angle (deg)
(3) Port 1 (6) Port 4 (c) Operating Torque (N·m)
Maker Nishina Industrial
Model –
Secondary pressure Noted separately
RY9212166HYM0033US0
3-M53 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Components
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Shim 4 0.1T (17) Bushing 2
(2) Shim 4 0.2T (18) Plug 1
(3) Seat 3 (19) Collar 4
(4) Spring seat 4 (20) Flanged plug 6
(5) Pushrod 4 (21) Hex socket bolt 4 JISB1176 M4×12×P0.7
JISB1176
(6) Pin 2 (22) Hex socket bolt 2
M10×25×P1.5
(7) Plate, name 1 (23) Hex set screw 4 JISB1177 M6x6
(8) Shim 4 0.2T (24) Flat metal washer 4 JISB1256
(9) Shim 4 0.1T (25) Rivet screw 2 #2×4.8
(10) Spool 4 (26) Parallel pin 4 JISB1354
(11) Body 1 (27) Steel ball 7 JISB1501
(12) Cover 2 (28) O-Ring 4 JISB2401 1A P10
(13) Cam 2 (29) O-Ring 6 JISB2401 1B P11
(14) Spring 4 (30) O-Ring 4 1B AS568-022
(15) Spring 4 (31) O-Ring 1 1B AS568-904
(16) Collar 4 (32) Expander 2
RY9212001HYM0115US0
3-M54 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Function and Structure
[A] Function
The pilot valve is the valve that controls the direction and volume of the stroke of the control valve, and lowers the
primary pressure from the unload valve to a secondary pressure only as much as is necessary to move the control
valve spool.
RY9212001HYM0001US0
[B] Operation
1. When the control lever is in neutral
The oil from the pilot pump that flows into Port P (a)
via the unload valve is cut off from port T (b) and port 1
(c) by the spool (10).
And port 1 is connected to port T through the inside
of the spool, so port 1 is at the tank pressure.
(10) Spool (a) Port P
(b) Port T
(c) Port 1
(d) Port 2
RY9212001HYM0116US0
2. When the control lever has been actuated (during
governing pressure)
When the cam (13) operating angle exceeds 1.9 °,
the pushrod (5) presses down on the spool (10) via the
spring seat (4) and the secondary pressure setting
spring (14).
At part A, port P (a) and port 1 (c) are connected,
while at part B, port 1 and port T (b) are cut off, so the oil
flows from port P to port 1.
When the pressure at port 1 gets high enough, it
counters the secondary pressure setting spring and
presses the spool up, thus cutting off port P and port 1 at
part A and allowing port 1 and port T to be connected at
part B, and lowering the pressure at port 1.
The repetition of this process maintains a constant
pressure equal to the secondary pressure setting spring
load.
If the cam is depressed further, the position of the
spool does not change and the pushrod and spring seat
move downwards, compressing the secondary pressure
setting spring and putting a large load on the spring; this
generates pressure equivalent to this load at port 1.
(4) Spring Seat (a) Port P
(5) Pushrod (b) Port T
(10) Spool (c) Port 1
(13) Cam (d) Port 2
(14) Spring
RY9212001HYM0117US0
3-M55 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
3. When the control lever has been actuated (during
short-circuit)
When the cam (13) operating angle exceeds 7.8 °,
the pushrod (5) and the hex socket bolt (22) come in
contact at part C and the spool (10) stops providing
control by balancing the pressure. As a result, part A is
left open, part B is left closed and the pressures of port
P and port 1 equalize.
(5) Pushrod (a) Port P
(10) Spool (b) Port T
(13) Cam (c) Port 1
(22) Hex Socket Bolt (d) Port 2
RY9212001HYM0118US0
3-M56 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[3] PILOT VALVE (SWING)
(1) Specifications
(1) Port P (5) Operating Torque (a) Secondary Pressure (e) Pushrod Stroke (mm)
(2) Port T (6) Secondary Pressure (kgf/cm2) (f) Pedal Operating Angle (deg)
(3) Port 1 (b) Secondary Pressure (MPa)
(4) Port 2 (c) Operating Torque (N·m)
(d) Operating Torque (kgf·cm)
Maker KPM (Kawasaki Precision Machinery)
Model PV6P1082A
Secondary pressure Noted separately
RY9212166HYM0034US0
3-M57 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Components
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Casing 1 (12) Spring seat 2
(2) Cover 1 (13) Washer 2
(3) Plug 2 (14) Spring 2
(4) Gasket 2 (15) Spring 2
(5) O-Ring 2 AS568-017 (16) Cam axle 1
(6) Pushrod 2 (17) Bushing 2
(7) Shim 2 (18) Cam 1
(8) RO plug 1 G1/4 (19) Steel ball 2
(9) O-Ring 1 JISB2401 P11 Hs90 (20) Hex set screw 1
(10) Hex socket bolt 2 JIS B 1176 SB-M6-16 (21) Bellows 1 HS50
(11) Spool 2
RY9212001HYM0120US0
3-M58 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Function and Structure
[A] Function
The pilot valve is the valve that controls the direction and volume of the stroke of the control valve, and lowers the
primary pressure from the unload valve to a secondary pressure only as much as is necessary to move the control
valve spool.
RY9212001HYM0001US0
[B] Operation
1. When the control lever or pedal are in neutral
The force of the secondary pressure setting spring
(14) does not press on the spool (11). As a result, the
spool is held in a neutral position by the return spring
(15). At such time, the output port (control valve port and
port 1 (a) and port 2 (b)) and port T (d) are connected.
2. When the control lever or pedal have been actuated
The cam (18) is turned counterclockwise, the port 1
side pushrod (6) presses down on the spool (11) via the
spring seat (12) and the secondary pressure setting
spring (14). When doing so, port P (c) and port 1 (a) are
connected, so the oil from the pilot pump flows through
port 1 to the control valve.
The pressure at port 1 rises until it is equivalent to the
force of the secondary pressure setting spring, thus
balancing the hydraulic pressure on the spool with the
tension of the secondary pressure setting spring and
maintaining a fixed port 1 pressure.
(6) Pushrod (a) Port 1
(11) Spool (b) Port 2
(12) Spring Seat (c) Port P
(14) Spring (d) Port T
(15) Spring
(18) Cam
RY9212001HYM0121US0
3-M59 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[4] PILOT VALVE (BLADE)
(1) Specifications
(1) Port 1 (a) Secondary Pressure (d) Operating Torque (kgf·cm) (g) Front
(2) Port 2 (kgf/cm2) (e) Push-Rod Stroke (mm) (h) Rear
(3) Port P (b) Secondary Pressure (MPa) (f) Operating Angle (deg)
(4) Port T (c) Operating Torque (N·m)
Maker KPM (Kawasaki Precision Machinery)
Model TH40P1048B
Secondary pressure Noted separately
RY9212166HYM0035US0
3-M60 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Components
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Casing 1 (19) Top cover 1
(2) Port plate 1 (20) Lever 1
(3) O-Ring 1 JIS B 2401 860 HS90 (21) Hex socket set screw 2 JIS B 1177 SSS-M12-10
(4) Socket head bolt 2 JIS B 1176 SB-M8-20 (22) Socket head bolt 2 JIS B 1176 SB-M8-16
(5) Bushing 1 (23) Disc 1
(6) Spool 2 (24) Cam axle 1
(7) Plug 2 (25) Hex socket set screw 1 JIS B 1177 SSS-M8-8
(8) Pushrod 1 (26) Bushing 2
(9) Pushrod 1 (27) Detent plug 2
(10) Seal 2 (28) Holder 2
(11) O-Ring 2 JIS B 2401 P20 HS90 (29) Steel ball 2 JIS B 1501, -3/16
(12) Washer 1 4 (30) Spring 2
(13) Spring seat 1 (31) Lock nut 2
(14) Spring seat 1 (32) Adjusting nut 2
(15) Washer 2 6 (33) O-Ring 2 JIS B 2401 P16 HS70
(16) Spring 2 (34) Socket head bolt 2 JIS B 1176 SB-M6-60
(17) Spring 1 (35) Bellows 1
(18) Spring 1
RY9212050HYM0001US0
3-M61 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Function and Structure
[A] Function
The pilot valve is the valve that controls the direction and volume of the stroke of the control valve, and lowers the
primary pressure from the unload valve to a secondary pressure only as much as is necessary to move the control
valve spool.
RY9212001HYM0001US0
[B] Operation
1. When the control lever is in neutral
The force of the secondary pressure setting spring
(17) does not come into effect. Consequently, spool (6)
is pushed up by the return spring (16), and port 1 (c) and
port T (b) are connected.
(6) Spool (a) Port P
(16) Spring (b) Port T
(17) Spring (c) Port 1
(d) Port 2
RY9212050HYM0018US0
2. When the control lever has been actuated
When the control lever is tilted and pushrod (8) goes
through its stroke, spool (6) moves downwards, port P
(a) and port 1 (c) are connected, and oil from the pilot
pump flows via port 2 to the control valve.
The pressure at port 1 rises until it is equivalent to the
force of the secondary pressure setting spring (17), thus
balancing the hydraulic pressure on the spool with the
tension of the secondary pressure setting spring and
maintaining a fixed port 1 pressure.
(6) Spool (a) Port P
(8) Pushrod (b) Port T
(17) Spring (c) Port 1
(d) Port 2
RY9212050HYM0019US0
3-M62 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
3. Pre-detent operation
Pre-detent is activated at a specified operating
angle. When steel ball (29) in the stepped section of the
disc (23) passes the step, operating torque increases
owing to compression of the spring (30). Due to this
change in operating torque, the operator knows he is
close to the actuation angle of detent operation at a
predetermined actuation angle.
(23) Disc (a) Port P
(29) Steel Ball (b) Port T
(30) Spring (c) Port 1
(d) Port 2
RY9212050HYM0020US0
4. When detent is activated
At the detent operation activation angle before the
end of stroke, the steel ball (29) slides into the V-shaped
groove of the disc (23), which is detent operation status.
If the operator releases the lever during detent
operation, the lever control angle is maintained and a
fixed secondary pressure continues to be applied.
(23) Disc (a) Port P
(29) Steel Ball (b) Port T
(c) Port 1
(d) Port 2
RY9212050HYM0021US0
5. When detent is released
Detent can be released manually by applying a force
greater than the release torque to the operating lever in
the direction of neutral.
RY9212050HYM0022US0
3-M63 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
9. UNLOAD VALVE
[1] SPECIFICATIONS
(1) PAC Port (Accumulator) (3) Port B (2-Speed Travel (5) Port P (to Control Valve) (7) Pilot Primary Relief Valve
(2) Port A (Pilot Operation, Swivel Switch) (6) Port C (from Pilot Pump) (aPP)
Parking Brake) (4) Drain Port (to Hydraulic Oil (8) Check Valve
Tank)
Maker Nishina Industrial Notes
Rated Voltage 12 V
3.92 +0.21 MPa
Relief Valve at Temp. 50 °C (144 °F),
40 +3.0 kgf/cm2
Pressure Setting 14.7 L/min (897 cu.in./min, 3.9 USGPM)
570 +43 psi
130 ml/min
Leak volume port P
7.9 cu.in./min at 2.5 MPa (25.5 kgf/cm2, 363 psi)
→ port T
0.03 USGPM
90 ml/min
Leak volume port
5 cu.in./min at 3.9 MPa (40.0 kgf/cm2, 569 psi)
PAC → other ports
0.02 USGPM
RY9212166HYM0036US0
3-M64 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] COMPONENTS
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Plug 1 (12) Solenoid 2
(2) Plunger 1 (13) Screw adjustment 1
(3) Spring 1 (14) Flanged plug 2
(4) Spring 2 (15) Hex socket bolt 4
(5) Spool 2 (16) Hex socket bolt 2
(6) Plunger 1 (17) Hex nut 1
(7) Spring 1 (18) Rivet screw 2
(8) Plate, name 1 (19) O-Ring 2
(9) Cover 1 (20) O-Ring 1
(10) Plug 1 (21) O-Ring 1
(11) Body 1 (22) O-Ring 2
RY9212001HYM0123US0
3-M65 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[3] FUNCTION AND STRUCTURE
(1) Function
The unload valve consists of two directional change valves operated by solenoid, a check valve and a relief valve;
it perform functions such as unloading control pressure from the pilot pump (returning oil to the hydraulic oil tank) and
supplying control pressures to pilot valves for operation and travel, as well as to the swivel motor (for the parking
brake) and the travel motor (for switching the two speeds).
RY9212001HYM0124US0
(2) Operation
With this device, oil from the pilot pump enters port C and is supplied to the control valve from port P, but that is
functionally identical to when oil from the pilot pump enters from port P and supplied to the control valve from port C.
Following is a description of when oil enters from port P from the pilot pump.
RY9212001HYM0125US0
1. When the solenoid is off
Oil from port P is cut off from passages to port A and
port T by a spool and plunger. Ports A and T are
connected. And Port C and Port P are connected, so the
pressures at port C and port P are always the same.
When the pressure from port P reaches the relief
valve pressure setting, the oil from port P returns to the
tank via the relief valve (pushes the plunger up).
(5) Spool A: Port A
(6) Plunger C: Port C
P: Port P
T: Port T
RY9212001HYM0126US0
3-M66 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
2. When the solenoid is on
When the solenoid is energized, the solenoid's
pushrod presses the spool down, connecting port P to
port A and cutting off port A and port T, so the oil from
port P flows to port A.
When port P pressure reaches a pressure at or
greater than the spring, the plunger moves to the right
and pressure oil flows from port P to port PAC.
When the pressure at port P is low, the oil from port
PAC is cut off, preventing backflow.
(3) Spring A: Port A
(5) Spool C: Port C
(6) Plunger P: Port P
(12) Solenoid T: Port T
RY9212001HYM0127US0
3-M67 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
10. SOLENOID VALVE
[1] SOLENOID VALVE FOR ANGLE BLADE
(1) Specifications
A : Port A B : Port B P : Port P T : Port T
Maker Nishina Industrial
Rated Voltage DC 12 V
220 ml/min or less
Leak Volume at Temp. 50 °C (122 °F), 4.9 MPa (50 kgf/cm2,
3130 psi) pressure
RY9212166HYM0037US0
(2) Components
No. Part Name Q'ty Notes No. Part Name Q'ty Notes
(1) Spring 2 (5) Flanged plug 3
(2) Spool 2 (6) Hex set screw 4
(3) Body 1 (7) O-Ring 2
(4) Solenoid 2 (8) O-Ring 3
RY9212050HYM0024US0
3-M68 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Function and Structure
The pressure from port P is supplied or cut off from port A or port B by the solenoid valve used when operating
the angle blade.
RY9212050HYM0025US0
1. When the solenoid is off
When the solenoid (4) is off, port P and Port B are cut
off by the spool (2). Port B and port T are connected, so
no pressure is produced at port B.
(2) Spool A: Port A
(4) Solenoid B: Port B
P: Port P
T: Port T
RY9212050HYM0026US0
2. When the solenoid is on
When the solenoid (4) is on, the spool (2) is pressed
down, connecting port P and port B. And as port B and
port T are cut off, the oil from port P flows to port B.
(2) Spool A: Port A
(4) Solenoid B: Port B
P: Port P
T: Port T
RY9212050HYM0027US0
3-M69 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] SOLENOID VALVE FOR AUX
(1) Specifications
This valve is an electromagnetic solenoid valve. Normally, a solenoid valve is turned off and on via 12V battery
voltage, but this valve is controlled via pulsed signals from the computer built into the ECU and the meter panel. (Duty
Control)
Item Specifications
3.9 MPa
Max operating pressure
40 kgf/cm2
(input pressure)
570 psi
1.0 MPa
Allowable back pressure
10 kgf/cm2
(pressure T)
100 psi
Maximum proportional valve
operating flow volume 15.6 L/min, 4.1 GPM
(input flow volume)
AUX1: 0.4 L/min ≥
AUX1, 2: 0.8 L/min ≥
Drain volume when solenoid off
(At 20 cST, port P pressure =
4.9 MPa, 50 kgf/cm2, 710 psi)
Waterproof Standard JIS D 0203 S2 equivalent
Vibration Proof Standard JIS D 1601–1995
Hydraulic Oil Grade ISO VG32 to 68 equivalent
Hydraulic Oil Contamination
NAS Class 10 ≥
Level
Rated Amperage: 1600 mA
Electrical Specifications Coil resistance: 3.2 ± 0.5 Ω
(at 20 °C, 68 °F)
0 to 2.7 MPa
Second pressure control range 0 to 27 kgf/cm2
0 to 390 psi
(1) Solenoid (A) AUX1
(2) Case (B) AUX1, 2
RY9212166HYM0028US0
3-M70 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Hydraulic Circuit Diagram
(1) Port P (A) AUX1
(2) Port T (B) AUX1, 2
(3) AUX1 High Pressure Port
(4) AUX1 Low Pressure Port
(5) AUX2 High Pressure Port
(6) AUX2 Low Pressure Port
RY9212032HYM0033US0
(1) Port P (A) Control Diagram
(2) Port T
(3) AUX1 High Pressure Port (a) Secondary Pressure (MPa)
(4) AUX1 Low Pressure Port (b) Input Current (mA)
(5) AUX2 High Pressure Port
(6) AUX2 Low Pressure Port
RY9212166HYM0029US0
3-M71 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Components
AUX1
(1) Filter (2) Adapter (3) AUX1 (SP1 High) (4) AUX1 (SP1 Low)
RY9212032HYM0038US0
AUX1, 2
(1) Filter (3) AUX1 (SP1 High) (5) AUX2 (SP2 High) (7) Base
(2) Adapter (4) AUX1 (SP1 Low) (6) AUX2 (SP2 Low)
RY9212032HYM0039US0
3-M72 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Solenoid Valve Installation
1. Adapter (3) installation (install as in the figure at left)
2. Adapter size: G1/4
24.5 to 29.4 N·m
Tightening torque Adapter (3) 2.5 to 3.0 kgf·m
18.1 to 21.7 lbf·ft
Be careful of hose contact when connecting.
For AUX1 Specification
3. Installation to the base (valve) (8)
23.5 to 27.5 N·m
Tightening torque M8 bolt (1) 2.4 to 2.8 kgf·m
17.4 to 20.2 lbf·ft
When equipped with both AUX 1 and 2
39.2 to 45.1 N·m
Tightening torque M10 bolt (1) 4.0 to 4.6 kgf·m
28.9 to 33.3 lbf·ft
(1) Bolt (5) AUX1 (SP1 Low)
(2) Filter (6) AUX2 (SP2 High)
(3) Adapter (7) AUX2 (SP2 Low)
(4) AUX1 (SP1 High) (8) Base
RY9212032HYM0040US0
3-M73 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Function and Structure
[A] Function
PWM (Pulse Width Modulation) Control
A PWM circuit is a method for controlling an actuator
by changing the duty cycle (ratio between pulse width H
and L), given a fixed cycle, of the pulse width according
to the magnitude of the input signal.
PWM control is an advanced form of pulse control
method and this method freely alters the width of the on
pulses of electricity.
In other words, PWM controls the energy supplied to
the actuator (cylinder) by controlling the pulse width.
• With the duty ratio (small at 20 %) of (1), the cylinder
only slightly in response, and the off time is the
longest.
• In (2) the duty ratio is 50 %, so the on time and off
time are equal, representing the middle of the control
circuit.
• In (3) the duty ratio of 80 % exerts the most energy,
which is reflected in the substantial movement of the
cylinder.
In short, PWM achieves its effect by controlling the
ratio of on-off time. This switching time is extremely
short.
RY9212032HYM0041US0
Merits:
Very little power is lost and fine movements of work
equipment can be controlled.
Demerits:
The circuitry is complex. And this complexity can
easily lead to high rates of failure and increased costs.
• PWM Cycle and Analog Strength Levels
The figure at left takes a motor as an example and
shows the relationship between the duty ratio and
analog strength. Even though previously it was
difficult to control the analog strength, with PWM
control it is easy to achieve precise control by
manipulating the duty ratio.
RY9212032AVM0023US0
3-M74 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Relationship between Lever Operation and Hydraulic Flow (Proportional Control)
(1) Right (Max) (3) Right (Idle) (A) AUX2 (a) Flow Volume L/min
(2) Left (Max) (4) Left (Idle) (B) AUX1 (b) Operating Lever Knob
(Limit Value)
The relationship between pressure P, flow Q and lever knob operation (limit value) changes proportionally as
shown in the figures above.
CAUTION
• There is deviation between machines on account of the n = 1 measurement being entered.
RY9212050HYM0008US0
3-M75 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[B] Structure
(A) Solenoid Valve Cross-section (AUX1 Spec)
(1) Hex Bolt (M5x0.8) (2) Proportional Control Solenoid (a) Port P (c) Port T
(b) Port A
7 ± 1 N·m
Tightening torque Hex bolt (1) 0.7 ± 0.1 kgf·m
5.2 ± 0.7 lbf·ft
NOTE
• The adjustment nut on top of the solenoid is set in advance when shipped from the factory.
• Service port flow. Do not adjust the feel with this nut. (Adjust according to the digital panel procedures.)
RY9212166HYM0041US0
3-M76 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(B) Function and Structure
The pressure from port P is supplied or cut off from port A or port B by the solenoid valve used when operating
the AUX.
RY9212095HYM0019US0
1. When the solenoid is off
When the solenoid is off, port P and port B are cut off
by the spool. Port B and port T are connected, so no
pressure is produced at port B.
(1) Spool A: Port A
(2) Solenoid B: Port B
P: Port P
T: Port T
RY9212095HYM0020US0
2. When the solenoid is on
When the solenoid is on, the spool is pressed down,
connecting port P and port B. And as port B and port T
are cut off, the oil from port P flows to port B.
(1) Spool A: Port A
(2) Solenoid B: Port B
P: Port P
T: Port T
RY9212095HYM0021US0
3-M77 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Knob Switch Configuration and Functions
Operating lever right
(1) Knob's Slide Switch (5) Knob Characteristics (a) Red (g) Green
(2) Remote Operation Control (6) Characteristic Circuit Diagram (b) Black (h) Blanking Pin
Knob (W/ One-Way Hold) (7) Diagram of Hydraulic Circuit (c) White (i) Proportional Control
(3) Harness Coupler (d) Blue (j) 45 °
(4) Side View of Entire Knob (e) Gray (k) 19 °
(f) Yellow (L) 25 °
This knob switch comes equipped with an IC chip that processes the signal of the potentiometer.
1. Service mode: set up in the service mode of the meter panel.
2. Knob control: Output can be controlled with the left/right knob switch to suit operating conditions.
3. Breaker operation: the button on the front of the operation lever can be used to switch to one-way hold.
RY9212166HYM0030US0
3-M78 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Knob Switch Configuration and Functions
Operating lever left
(1) Knob's Slide Switch (5) Knob Characteristics (a) Red (g) Green
(2) Remote Operation Control (6) Characteristic Circuit Diagram (b) Black (h) Blanking Pin
Knob (W/ One-Way Hold) (7) Diagram of Hydraulic Circuit (c) White (i) Proportional Control
(3) Harness Coupler (d) Blue (j) 45 °
(4) Side View of Entire Knob (e) Gray (k) 19 °
(f) Yellow (L) 25 °
This knob switch comes equipped with an IC chip that processes the signal of the potentiometer.
1. Service mode: set up in the service mode of the meter panel.
2. Knob control: Output can be controlled with the left / right knob switch to suit operating conditions.
RY9212166HYM0031US0
3-M79 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(Ex.) Thumb Hydraulic Circuit Diagram
(1) Main Pump (3) Main Control Valve, Service (4) Thumb Cylinder (a) PWM Signal
(2) Main Pump Pp Port Section (b) Bottom (Thumb Crowd)
(c) Rod (Thumb Dump)
RY9212032AVM0029US0
3-M80 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[3] EP MODE SOLENOID VALVE
(1) Specifications
Item Specifications
3.9 MPa
Max operating pressure
40 kgf/cm2
(input pressure)
570 psi
1.0 MPa
Allowable back pressure
10 kgf/cm2
(pressure T)
100 psi
Maximum proportional valve
operating flow volume 10.0 L/min (2.64 U.S. gal./min.)
(input flow volume)
0.6 L/min (0.2 U.S. gal./min.) ≥
Drain volume when solenoid off [At 20 cST, port P pressure =
4.9 MPa (50 kgf/cm2, 710 psi)]
Rated Amperage: 1600 mA
Electrical Specifications Coil resistance: 3.3 Ω (at 20 °C
(68 °F))
(1) Solenoid A : Port A
(2) Case P: Port P
T: Port T
(a) Hydraulic Pressure
Symbols
RY9212166HYM0040US0
(A) Control Characteristics (a) Secondary Pressure (MPa)
Chart (b) Input Amperage (mA)
RY9212166HYM0042US0
3-M81 KiSC issued 04, 2021 A
SERVICING
CONTENTS
1. PUMP ..........................................................................................................................................3-S1
[1] PUMP DISASSEMBLY / ASSEMBLY ...................................................................................3-S1
2. CONTROL VALVE.......................................................................................................................3-S5
[1] CONTROL VALVE REMOVAL ..............................................................................................3-S5
3. SWIVEL MOTOR.........................................................................................................................3-S9
[1] REMOVAL AND INSTALLATION OF THE SWIVEL MOTOR...............................................3-S9
[2] SWIVEL MOTOR ASSEMBLY PROCEDURES ..................................................................3-S12
(1) Assembly Procedures....................................................................................................3-S14
4. SWIVEL JOINT..........................................................................................................................3-S23
[1] SWIVEL JOINT INSTALLATION AND REMOVAL ..............................................................3-S23
[2] SWIVEL JOINT....................................................................................................................3-S25
5. TRAVEL MOTOR ......................................................................................................................3-S29
[1] REMOVAL AND INSTALLATION OF THE TRAVEL MOTOR ............................................3-S29
[2] TRAVEL MOTOR DISASSEMBLY / ASSEMBLY PROCEDURES .....................................3-S32
(1) Disassembly Procedures...............................................................................................3-S34
(2) Assembly Procedures....................................................................................................3-S44
[3] SPECIAL TOOLS ................................................................................................................3-S58
6. HYDRAULIC CYLINDER...........................................................................................................3-S61
[1] HYDRAULIC CYLINDER DISASSEMBLY / ASSEMBLY PROCEDURES..........................3-S61
(1) Cylinder Components ....................................................................................................3-S61
(2) Disassembly Procedures...............................................................................................3-S63
(3) Assembly Procedures....................................................................................................3-S67
7. PILOT VALVE (CONTROL).......................................................................................................3-S74
[1] PILOT VALVE (CONTROL) ASSEMBLY ...........................................................................3-S74
[2] PILOT VALVE (CONTROL) DISASSEMBLY / ASSEMBLY PROCEDURES......................3-S75
(1) Pilot Valve Components ................................................................................................3-S75
(2) Disassembly ..................................................................................................................3-S75
(3) Assembly .......................................................................................................................3-S79
(4) U-Joint Tightening Tool .................................................................................................3-S82
8. PILOT VALVE (TRAVEL) ..........................................................................................................3-S83
[1] PILOT VALVE (TRAVEL) ASSEMBLY ................................................................................3-S84
[2] PILOT VALVE (TRAVEL) DISASSEMBLY / ASSEMBLY PROCEDURES .........................3-S85
(1) Disassembly Procedures...............................................................................................3-S85
(2) Assembly Procedures....................................................................................................3-S89
9. PILOT VALVE (SWING) ............................................................................................................3-S94
[1] PILOT VALVE (SWING) DISASSEMBLY............................................................................3-S94
[2] PILOT VALVE (SWING) ASSEMBLY..................................................................................3-S97
10. PILOT VALVE (BLADE)...........................................................................................................3-S102
[1] PILOT VALVE (BLADE) ASSEMBLY ................................................................................3-S102
[2] PILOT VALVE (BLADE) DISASSEMBLY GUIDE..............................................................3-S103
(1) Disassembly ................................................................................................................3-S104
(2) Assembly .....................................................................................................................3-S106
11. UNLOAD VALVE .....................................................................................................................3-S109
[1] UNLOAD VALVE ASSEMBLY...........................................................................................3-S109
[2] UNLOAD VALVE DISASSEMBLY / ASSEMBLY PROCEDURES ....................................3-S110
(1) Disassembly / Assembly Procedures ..........................................................................3-S111
12. TPSS VALVE...........................................................................................................................3-S114
[1] TPSS VALVE.....................................................................................................................3-S114
(1) Specifications ..............................................................................................................3-S114
KiSC issued 04, 2021 A
(2) Components ................................................................................................................3-S115
13. THIRD LINE VALVE ASSEMBLY ............................................................................................3-S116
[1] THIRD LINE VALVE ASSEMBLY COMPONENTS ...........................................................3-S116
[2] THIRD LINE HOSE ROUTE ..............................................................................................3-S117
14. ROUTING OF HYDRAULIC HOSES .......................................................................................3-S118
[1] TABLE OF HYDRAULIC HOSES ......................................................................................3-S118
(1) Hydraulic Hoses...........................................................................................................3-S118
(2) Table of High-Pressure Hoses.....................................................................................3-S119
(3) Deliver Hose Routing...................................................................................................3-S122
(4) Delivery Hose Clamp Positions ...................................................................................3-S123
(5) Suction Pipe and Hose Routing...................................................................................3-S124
(6) Installation of Pipes (Suction) ......................................................................................3-S125
(7) Front Hose Routing (U55-4) ........................................................................................3-S125
(8) Front Hose Routing (KX057-4) ....................................................................................3-S126
(9) High-Pressure Hydraulic Hose Routing (Front) ...........................................................3-S127
(10)High-Pressure Hydraulic Hose Routing (Travel, Swivel, Blade, Swing) ......................3-S127
(11)High-Pressure Hydraulic Hose Routing (Travel, Swivel, Blade, Angle, Swing)...........3-S128
(12)High-Pressure Hydraulic Hose Routing (Travel, Blade Swivel)...................................3-S128
(13)High-Pressure Hydraulic Hose Routing (Travel, Blade, Angle, Swivel).......................3-S129
(14)Hose Routing Inside the Track Frame (Standard Spec) .............................................3-S130
(15)Hose Routing Inside the Track Frame (Angle Spec) ...................................................3-S131
(16)Swivel Hose Routing (KX057-4) ..................................................................................3-S132
(17)Swivel Hose Routing (U55-4) ......................................................................................3-S133
[2] TABLE OF HYDRAULIC HOSES (LOW-PRESSURE HOSES) ........................................3-S134
(1) Table of Hydraulic Hoses.............................................................................................3-S134
(2) Table of Protective Tubing...........................................................................................3-S134
(3) Drain Hose Routing .....................................................................................................3-S135
[3] TABLE OF HYDRAULIC HOSES (PILOT HOSES)...........................................................3-S136
(1) Table of Pilot Hoses.....................................................................................................3-S136
(2) Pilot Hose Routing (P) .................................................................................................3-S140
(3) Pilot Hose Routing (P) .................................................................................................3-S140
(4) Pilot Hose Routing (T) .................................................................................................3-S141
(5) Pilot Hose Routing (Front) ...........................................................................................3-S142
(6) Pilot Hose Routing (Travel, Blade, Swing, AUX1, AUX2)............................................3-S143
(7) Pilot Hose Routing (Travel, Blade, Swing, AUX1, AUX2, Angle).................................3-S144
(8) Pilot Hose Routing (Control Valve) (KX057-4).............................................................3-S145
(9) Pilot Hose Routing (Control Valve) (U55-4).................................................................3-S146
(10)Overall Routing of Pilot Hoses (Front of Machine) (KX057-4).....................................3-S147
(11)Overall Routing of Pilot Hoses (Front of Machine) (U55-4) .........................................3-S148
(12)Overall Routing of Pilot Hoses (Right Side of Machine) (KX057-4) ............................3-S149
(13)Overall Routing of Pilot Hoses (Right of Machine) (U55-4) .........................................3-S150
(14)Pilot Hose Routing (Around the Driver's Seat) ............................................................3-S151
15. HYDRAULIC DEVICE PERFORMANCE MEASUREMENT....................................................3-S152
16. CHART OF MEASURED VALUES FOR HYDRAULIC DEVICE PERFORMANCE ................3-S170
17. TROUBLESHOOTING.............................................................................................................3-S177
KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
1. PUMP
[1] PUMP DISASSEMBLY / ASSEMBLY
CAUTION
• When removing a hydraulic device after operating the machine, lower the bucket and blade to the ground
and turn off the engine.
• Each of the devices and the hydraulic oil are hot and under high pressure immediately after operating the
machine. If the hydraulic oil reached a high operating temperature, it may cause a burn.
• Oil gushing out under pressure has enough force to pierce your skin and may cause you injury.
Always allow the temperature to drop and relieve any remaining pressure prior to working to remove any
hydraulic equipment.
RY9212001MBS0004US0
Removing the rear bonnet
1. Open the rear bonnet, remove the bolts and detach the rear
bonnet.
(1) Rear Bonnet (2) Bolt
RY9212166HYS0132US0
Removing the left bonnet
1. Remove the left bonnet mounting bolts and the fuel tank cap,
and then remove the left bonnet.
(1) Left Bonnet (3) Bolt (M10 X 25)
(2) Bolt (M10 X 35)
RY9212166HYS0109US0
Removing the cover
1. Remove the bolts in two locations, and remove the cover.
(1) Cover (2) Bolt (M10 x 30)
RY9212166HYS0110US0
Removing the cover and bracket
1. Remove the bolts at four points, and remove the bottom cover
of the fuel filler port.
Remove the mounting bolts on the rear bonnet fixing bracket
and then remove the bracket.
(1) Bolt (M10 X 20) (3) Bracket
(2) Cover
RY9212166HYS0133US0
3-S1 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Removing the pump bottom cover
1. Remove the bolts in three locations, and remove the bottom
cover from the underside of the pump.
(1) Cover (2) Bolt (M10 × 20)
RY9212166HYS0111US0
Attaching the vacuum pump
1. Attach the breather hose of the hydraulic tank to the vacuum
pump, and apply vacuum pressure to the hydraulic tank.
(1) Breather Hose (2) Pneumatic Vacuum Pump
RY9212166HYS0112US0
Removing the main pump
1. Remove all hoses from the pump, and fit plugs to the adapter
and disconnected hoses.
2. Loosen the suction hose tightening clamp, and remove the
suction hose from the pump.
(1) Pump Assembly (Piston) (4) Hose (Suction 1)
(3) Hose Clamp
RY9212166HYS0113US0
3-S2 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
3. Suspend the pump by a nylon sling, and support with a crane.
Remove the bolts in two locations, and pull the shaft of the pump
suspended by the crane from the coupling.
196.1 to 225.6 N·m
Tightening torque Pump assembly (piston) 20 to 23 kgf·m
144.6 to 166.4 lbf·ft
• Pump weight : Approx. 38 kg (84 lbs)
(2) Bolt (M16 x 35) (6) Coupling
(5) Nylon Sling
RY9212166HYS0135US0
Pump adapter angles
(1) Pipe Joint (L, G4-G4) P1
(2) Pipe Joint (G4-G4) P2
(3) Pipe Joint (L, G4-G4) P3
(4) Straight Pipe Joint Pp
(5) Pipe Joint (L, G1/4-G1/4)
PPS
(6) Pipe Joint (L, G1/4-G1/4)
PLS
(7) Pipe Joint (L, G1/4-G1/4) Air
Bleed
(8) Pipe Joint (L, G1/4-G1/4)
(a) 60 °
(b) 45 °
(c) 30 °
RY9212166HYS0008US0
3-S3 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Pump coupling block diagram
Tightening the coupling assembly bolts
Apply an extremely thin layer of lubricating oil to the coupling
seat surface, then tighten to the torque indicated in the following
table.
85 to 94 N·m
Tightening torque Bolt (coupling) (2) 8.7 to 9.6 kgf·m
63 to 69 lbf·ft
IMPORTANT
• Do not apply a threadlock.
(1) Coupling (a) Spline Section Grease
(2) Bolt (Coupling) Application
(3) Housing (Pump) (b) Apply an Extremely thin Layer of
(4) Bolt (M10 × 25) Lubricating Oil to the Coupling
Seat Surface before Tightening
RY9212166HYS0010US0
3-S4 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
2. CONTROL VALVE
[1] CONTROL VALVE REMOVAL
CAUTION
• When removing a hydraulic device after operating the machine, lower the bucket and blade to the ground
and turn off the engine.
• Each of the devices and the hydraulic oil are hot and under high pressure immediately after operating the
machine. If the hydraulic oil reached a high operating temperature, it may cause a burn.
• Oil gushing out under pressure has enough force to pierce your skin and may cause you injury.
Always allow the temperature to drop and relieve any remaining pressure prior to working to remove any
hydraulic equipment.
RY9212001MBS0004US0
Removing the right bonnet
1. Open the right bonnet, remove the two snap pins, and separate
the gas damper from the bonnet.
2. Slide the right bonnet to the front of the body and remove.
CAUTION
• The task of removing the right bonnet must be carried out
by at least two persons.
• Weight of right bonnet : approx. 27 kg (60 lbs)
(1) Snap Pin - Flat Metal Washer (3) Gas Damper
(2) Snap Pin - Flat Metal Washer (4) Right Bonnet
RY9212166HYS0114US0
Removing the right cover assembly
1. Remove the fixing bolts on the right cover assembly, and
remove the right cover assembly.
(1) Right Cover Assembly (2) Bolt (M10 X 25)
RY9212166HYS0115US0
3-S5 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Removing the battery
1. Remove the retainer (3) fastening nuts (6), and remove the
cover (2) and retainer (3).
2. Disconnect the battery cord (negative) (8) and battery cord
(positive) (7) from the battery side, and remove the battery from
the machine.
WARNING
• When disconnecting the battery cords, be sure to
disconnect the negative cord first. When re-connecting,
connect the positive cord first.
(1) Battery (105D31L) (5) Flat Metal Washer
(2) Cover (6) Nut
(3) Retainer (7) Battery Cord (Positive)
(4) Bolt (8) Battery Cord (Negative)
RY9212001HYS0132US0
Removing the hydraulic hoses
1. Attach the breather hose of the hydraulic fluid tank to the
vacuum pump, and apply vacuum pressure to the hydraulic fluid
tank.
2. Disconnect all hydraulic hoses and electrical wiring from the
control valve.
CAUTION
• Plug all disconnected hydraulic hoses, and affix
identification labels on each for reassembly.
RY9212001HYS0133US0
Removing the control valve
1. Fit an eyebolt (M10 pitch 1.25) (6) into the bracket (1) bolt hole,
and suspend the control valve assembly (2) by the crane.
2. Remove the mounting bolts (3) and (4) (six locations) of the
bracket (1), and remove using the crane.
• Control valve weight :
59.5 kg (131 lbs) [STD version]
63 kg (140 lbs) [Angle blade version]
77.5 to 90.2 Nm
Tightening torque Bracket (1) 7.9 to 9.2 kgf·m
57.2 to 66.5 lbf·ft
IMPORTANT
• Apply a threadlock (Loctite #271).
(1) Bracket (4) Bolt (M12x25)
(2) Control Valve Assembly (5) Flat Metal Washer
(3) Bolt (M12x25) (6) Eyebolt (M10 Pitch 1.25)
RY9212050HYS0105US0
3-S6 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Control valve assembly diagram
(1) Bracket (3) Bolt (M12 x 25) (a) Mounting Hole Always Used (d) Mounting Hole to Use for
(2) Control Valve (4) Bolt (M12 x 25) (b) Mounting Hole Always Used AUX2 Spec
(c) Hole Not Used (e) Mounting Hole to Use for
Angle Spec
RY9212050HYS0040US0
Removing the control valve assembly
1. Remove the control valve assembly (1) mounting bolts (3), and
remove the control valve assembly from the bracket (2).
48.1 to 55.9 N·m
Tightening torque Control valve assembly (1) 4.9 to 5.7 kgf·m
35.5 to 41.2 lbf·ft
IMPORTANT
• Apply a threadlock (Loctite #271).
(1) Control Valve Assembly (3) Flange Bolt (M10 × 20)
(2) Bracket
RY9212032HYS0015US0
3-S7 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Control Valve (Angle Specs) Adapter Installation Angles
(1) Control Valve Assembly (11) Boom, Bottom (20) Swing, Rod (a) 20 °
(2) T1, PLS (12) Boom, Rod (21) Blade, Rod (b) 30 °
(3) AUX1. Low (13) P1, P2, PPS (22) Blade, Bottom (c) 45 °
(4) AUX1. High (14) Travel Right Forward (23) AUX2, Low (d) 60 °
(5) Swivel Right (15) Travel Right Rear (24) AUX2, High
(6) Swivel Left (16) Travel Left Forward (25) Angle, Bottom
(7) Bucket, Bottom (17) Travel Left Rear (26) Angle, Rod
(8) Bucket, Rod (18) P3, T2 (27) Pp1, Pai
(9) Arm, Bottom (19) Swing, Bottom (28) T3
(10) Arm, Rod
RY9212050HYS0041US0
3-S8 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
3. SWIVEL MOTOR
[1] REMOVAL AND INSTALLATION OF THE SWIVEL MOTOR
CAUTION
• When removing a hydraulic device after operating the machine, lower the bucket and blade to the ground
and turn off the engine.
• Each of the devices and the hydraulic oil are hot and under high pressure immediately after operating the
machine. If the hydraulic oil reached a high operating temperature, it may cause a burn.
• Oil gushing out under pressure has enough force to pierce your skin and may cause you injury.
Always allow the temperature to drop and relieve any remaining pressure prior to working to remove any
hydraulic equipment.
RY9212001MBS0004US0
Removing the cab
1. Put the bucket on the ground and stop the engine.
Remove the cab.
(Refer to the chapter Cab Removal and Installation.)
107.9 to 127.4 N·m
Tightening torque Nut 11.0 to 13.0 kgf·m
79.6 to 94.0 lbf·ft
RY9212166HYS0116US0
Removing the step
1. Remove the step (1) and the cover (2).
(1) Step (2) Cover
RY9212166HYS0136US0
Removing ducts
1. Remove the cover (duct) (1) and the duct ASSY (2).
(1) Cover Duct (2) Duct, ASSY
RY9212001HYS0170US0
3-S9 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Removing the swivel motor
1. Disconnect the hydraulic hoses (1) to (6) around the motor
ASSY (swivel) at the motor.
2. Remove the eight mounting bolts (7) to the motor ASSY
(swivel).
IMPORTANT
• Apply a threadlock (Loctite #271).
259.9 to 304.0 N·m
Tightening torque Motor ASSY (swivel) 26.5 to 31.0 kgf·m
191.7 to 224.2 lbf·ft
(1) Hydraulic Hose (5) Hydraulic Hose
(2) Hydraulic Hose (6) Hydraulic Hose
(3) Hydraulic Hose (7) Bolt (M16 × 45)
(4) Hydraulic Hose
RY9212166HYS0022US0
3. Suspend the motor ASSY (swivel) (9) from a nylon sling (8) and
hoist it up with a crane.
(8) Nylon Sling (9) Motor ASSY (Swivel)
RY9212050HYS0111US0
3-S10 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Swivel Motor Adaptor Layout Diagram
(1) Motor, ASSY (Swivel) (5) Pipe Joint (T, G2, G2-G2) (a) Swivel Right (d) P-Block (Tank)
(2) Pipe Joint (S G4, G4) (6) Pipe Joint (L, G1/4-G3/8) (b) Swivel Left (e) Travel Pilot V and Swing
(3) Pipe Joint (S G4, G4) (7) Pipe Joint (L, G2-13) (c) Apply Grease to and Install Pilot V
(4) Pipe Joint (S G4, G4) the Rabbeted Flange and (f) Front of Machine
the Pinion.
RY9212001HYS0175US0
3-S11 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] SWIVEL MOTOR ASSEMBLY PROCEDURES
No. Part Name Q'ty No. Part Name Q'ty
(1) Shaft (pinion) 1 (14) Plate (thrust 2) 4
(2) Plate (pinion 2) 1 (15) External circlip 4
(3) Plate (pinion) 1 (16) Gear (sun) 1
(4) Plate (valve) 1 (17) External circlip 1
(5) Tapered roller bearing 1 (18) Holder (1) 1
(6) Gear case 1 (19) Collar (1) 3
(7) Oil Seal 1 (20) Needle bearing 3
(8) Tapered roller bearing 1 (21) Gear (planetary 1) 3
(9) Spacer (t = 5.30 mm, 0.21 in.) 2 (22) Gear (drive) 1
(9) Spacer (t = 5.45 mm, 0.22 in.) 2 (23) Plate (thrust) 1.8 mm, 0.07 in. 1
(9) Spacer (t = 5.60 mm, 0.22 in.) 2 (23) Plate (thrust) 2.3 mm, 0.09 in. 1
(9) Spacer (t = 5.75 mm, 0.23 in.) 2 (23) Plate (thrust) 2.9 mm, 0.11 in. 1
(9) Spacer (t = 5.90 mm, 0.23 in.) 2 (23) Plate (thrust) 3.2 mm, 0.13 in. 1
(10) Holder 2 1 (24) O-Ring 1
(11) Collar 2 4 (25) Hex socket bolt 2
(12) Needle bearing 4 (26) O-Ring 1
(13) Gear (planetary 2) 4 (27) Filter 1
3-S12 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
No. Part Name Q'ty No. Part Name Q'ty
(28) O-Ring 1 (57) Ball bearing 1
(29) Plug (G1/2) 1 (58) Shaft 1
(30) O-Ring 1 (59) Thrust plate 1
(31) Plug (G1/4) 1 (60) Plate (retainer) 1
(32) Poppet 2 (61) Holder (retainer) 1
(33) Compression spring 2 (62) Piston, ASSY 9
(34) O-Ring 2 (63) Pin 3
(35) Plug 2 (64) Plate (friction) 1
(36) Piston (shockless) 1 (65) Cylinder block (swivel) 1
(37) O-Ring 2 (66) Metal washer (spring 2) 1
(38) Plug (G1/2) 2 (67) Spring (CY) 1
(39) Housing (motor and valves) 1 (68) Metal washer (spring 2) 1
(40) Backup ring 4 (69) Internal circlip 1
(41) O-Ring 2 (70) O-Ring 1
(42) Ring (Poppet seat) 2 (71) Piston (brake) 1
(43) Poppet 2 (72) Spring (NB) 12
(44) Ring (backup) 4 (73) O-Ring 1
(45) O-Ring 2 (74) Plate (valve) 1
(46) O-Ring 2 (75) Ball bearing 1
(47) Housing (relief) 2 (76) O-Ring 1
(48) Ring (spring seat) 2 (77) Parallel pin 1
(49) Compression spring 2 (78) Plug (R1/4) 2
(50) Backup ring 2 (79) O-Ring 2
(51) O-Ring 2 (80) Parallel pin 2
(52) Guide (spring) 2 (81) Parallel pin 2
(53) O-Ring 2 (82) O-Ring 2
(54) Plug (relief) 2 (83) Hex socket bolt 7
(55) Set screw 2 (84) Cover (motor) 1
(56) Nut 2
RY9212001HYS0177US0
3-S13 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(1) Assembly Procedures
1. Use the jig (7) to tap the oil seal into the gear case (6).
IMPORTANT
• Apply grease to the lip and circumference of the oil seal.
(6) Gear Case (A) Tap in Tool
(7) Oil Seal (a) 99 ± 0.05 mm ( 3.9 ± 0.002 in.)
(b) 89 ± 0.05 mm ( 3.5 ± 0.002 in.)
RY9212166HYS0023US0
2. Press the outer race of the tapering roller bearing all the way
into the gear case (6).
(6) Gear Case (7) Oil Seal
RY9212001HYS0179US0
3-S14 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
3. Install to the shaft (pinion) (1) in order of plate (pinion 2) (2),
plate (pinion) (3) and plate (seal) (4).
IMPORTANT
• Be careful of its direction when pressing the inner race of
the tapering roller bearing (5) onto the shaft (1).
• After installing it, encapsulate the inner race of the tapering
roller bearing with grease.
• Amount of grease : about 50 cc (0.04 U.S.gal)
(1) Shaft (Pinion) (A) Grease
(2) Plate (Pinion 2)
(3) Plate (Pinion)
(4) Plate (Valve)
(5) Tapered Roller Bearing
RY9212001HYS0180US0
4. Press the shaft (pinion) (1) into the gear case.
IMPORTANT
• Do not scratch the oil seal.
(1) Shaft (Pinion)
RY9212001HYS0181US0
3-S15 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
5. Press the inner race of the tapering roller bearing (8) onto the
shaft.
IMPORTANT
• Be careful to install the inner race facing the right direction.
• After installing it, rotate the shaft by hand.
• Select and install a spacer (9) so that the gap is between 0
to 0.15 mm (0.006 in.).
(6) Gear Case (9) Spacer
RY9212001HYS0182US0
6. Install the collar (11), needle bearing (12), gear (planetary 2)
(13) and plate (thrust 2) (14) onto holder 2 (10).
7. Install the gear (sun) (16).
IMPORTANT
• Be careful to install the gears (planetary 2) facing the right
direction.
• Install the gears (planetary 2) so the end without an
indentation faces the holder 2.
• Install the plates (thrust 2) and external circlips (15) with
the R face down.
• Tool to use : snap ring pliers
(10) Holder 2 (14) Plate (Thrust 2)
(11) Collar 2 (15) External Circlip
(12) Needle Bearing (16) Gear (Sun)
(13) Gear (Planetary 2) (17) External Circlip
RY9212001HYS0183US0
3-S16 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
8. Install the collar (19), needle bearing (20) and gear (planetary 1)
(21) onto holder 1 (18).
9. Install the gear (drive) (22).
10. Install the O-ring (24) on the gear case(6).
IMPORTANT
• Be careful to install the gears (planetary 1) and (drive)
facing the right direction.
• Install the gear (drive) so the indented face is toward the
holder 1.
• Install the gear (planetary 1) so the indented face is toward
the plate (thrust).
• Apply grease to the O-ring.
(6) Gear Case (21) Gear (Planetary 1)
(18) Holder (1) (23) Plate (Thrust)
(19) Collar (1) (22) Gear (Drive)
(20) Needle Bearing (24) O-Ring
RY9212001HYS0184US0
11. Measure the distance A between the top of the gear (planetary
1) and the top of the gear case.
IMPORTANT
• Select the appropriate plate (thrust) from the table below to
suit the measurement of distance A.
Distance A Part to Install Thickness
5.50 to 6.00 mm 1.8 mm
FD411-1727
0.22 to 0.24 in. 0.07 in.
6.00 to 6.60 mm 2.3 mm
FD411-1728
0.24 to 0.26 in. 0.09 in.
6.60 to 6.90 mm 2.9 mm
FD411-1729
0.26 to 0.27 in. 0.11 in.
6.90 to 7.40 mm 3.2 mm
FD411-1730
0.27 to 0.29 in. 0.13 in.
(6) Gear Case (39) Housing (Motor and Valves)
(23) Plate (Thrust)
RY9212166HYS0024US0
12. Install the selected plate (thrust) (23).
(23) Plate (Thrust)
RY9212001HYS0186US0
3-S17 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
13. Install the ball bearing (57) on the shaft (58).
14. Install the shaft ASSY into the housing (39).
IMPORTANT
• When installing the bearing (57) in the housing (motor,
valve), install it so its inscription is visible.
• Dip the thrust plate (59) in hydraulic oil and install it so the
beveled side faces the housing.
• Tool to use : plastic hammer
(39) Housing (Motor and Valves) (76) O-Ring
(57) Ball Bearing (79) O-Ring
(58) Shaft (82) O-Ring
(59) Thrust Plate
RY9212001HYS0187US0
15. Install the metal washer (spring) (66), spring CY (67), metal
washer (spring) (68) and internal circlip (69) in the cylinder block
(65).
IMPORTANT
• Install the internal circlip (69) so its R face is toward the
piston.
• Apply grease to the pin and install it in the holder (retainer)
(61) and the plate (retainer) (60) in order.
(60) Plate (Retainer) (65) Cylinder Block (Swivel)
(61) Holder (Retainer) (66) Metal Washer (Spring)
(62) Piston (67) Spring CY
(63) Pin (68) Metal Washer (Spring)
(64) Plate (Friction) (69) Internal Circlip
RY9212001HYS0188US0
3-S18 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
16. Lay the housing on its side.
17. Install the cylinder block sub-assembly B1, using the spline of
the shaft (58) as a guide.
IMPORTANT
• Be careful not to drop the pin.
• Dip the whole ASSY in hydraulic oil and then install it.
• After installing the ASSY, check and make sure the plate
(friction) is not tilted.
• Press on the cylinder block sub-assembly B1 and make
sure the spring CY is working.
(57) Ball Bearing (72) Spring (NB)
(58) Shaft (73) O-Ring
(59) Thrust Plate (76) O-Ring
(64) Plate (Friction)
(70) O-Ring B1 : Cylinder Block Sub-Assembly
(71) Piston (Brake)
RY9212001HYS0189US0
18. Check the O-ring on the gear case side and install the housing
(motor, valves) on the gear case.
19. Fasten it with the hex socket bolts (25).
102.9 to 117.6 N·m
Tightening torque Hex socket bolt (25) 10.5 to 12.0 kgf·m
75.9 to 86.7 lbf·ft
• Tool to use : M10 hex socket
(25) Hex Socket Bolt (M12)
RY9212166HYS0025US0
20. Install O-rings (73) and (70) to the piston (brake) (71).
IMPORTANT
• Apply grease to the O-ring.
(70) O-Ring (73) O-Ring
(71) Piston (Brake)
RY9212001HYS0191US0
3-S19 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
21. Install the piston (brake) (71), keeping it parallel to its mating
surface (housing and motor valves) as you do so.
IMPORTANT
• Be careful to install the piston (brake) facing the right
direction.
• Check and make sure that the rotation-checking holes in
the piston (brake) line up with the center of the shaft and
the center of the pin.
• Tool to use : plastic hammer
(58) Shaft (81) Pin
(71) Piston (Brake)
RY9212001HYS0192US0
22. Install O-rings (76) and (79).
23. Install the spring (NB) (72) in the piston.
IMPORTANT
• Apply grease to the O-ring.
(72) Spring (NB) (79) O-Ring
(76) O-Ring (82) O-Ring
RY9212001HYS0193US0
24. Install the ball bearing (75) on the cover (motor) (84).
25. Install the plate (valve) (74) on the cover (84).
IMPORTANT
• When installing the ball bearing (75), install it so its
inscription is visible.
• Apply grease on the plate (74) and stick it to the cover (84).
• Tool to use : plastic hammer
(74) Plate (Valve) (84) Cover (Motor)
(75) Ball Bearing
RY9212001HYS0194US0
26. Install the cover on the housing (motor, valves).
27. Fasten it with the hex socket bolts (83).
IMPORTANT
• Be careful not to drop any valves (plate).
102.9 to 117.6 N·m
Tightening torque Hex socket bolt (83) 10.5 to 12.0 kgf·m
75.9 to 86.7 lbf·ft
• Tool to use : M10 hex socket
(83) Hex Socket Bolt (M12)
RY9212166HYS0026US0
3-S20 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
28. Install the valve ASSY (relief) (47).
58.5 to 68.6 N·m
Tightening torque Valve ASSY (relief) (47) 6.0 to 7.0 kgf·m
43.1 to 50.6 lbf·ft
• Tool to use : wrench (socket) M26
(47) Valve ASSY (Relief)
RY9212166HYS0027US0
29. Apply hydraulic oil to the piston (shockless) (36) and install it.
58.5 to 68.6 N·m
Tightening torque Plug (38) 6.0 to 7.0 kgf·m
43.1 to 50.6 lbf·ft
• Tool to use : M10 hex socket
(36) Piston (Shockless) (38) Plug (G1/2)
(37) O-Ring
RY9212166HYS0028US0
3-S21 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
30. Install the poppet (makeup) (32).
49.0 to 58.8 N·m
Tightening torque Plug (35) 5.0 to 6.0 kgf·m
36.1 to 43.4 lbf·ft
• Tool to use : M8 hex socket
(32) Poppet (35) Plug
(33) Compression Spring (39) Housing (Motor and Valves)
RY9212166HYS0029US0
3-S22 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
4. SWIVEL JOINT
[1] SWIVEL JOINT INSTALLATION AND REMOVAL
CAUTION
• When removing a hydraulic device after operating the machine, lower the bucket and blade to the ground
and turn off the engine.
• Each of the devices and the hydraulic oil are hot and under high pressure immediately after operating the
machine. If the hydraulic oil reached a high operating temperature, it may cause a burn.
• Oil gushing out under pressure has enough force to pierce your skin and may cause you injury.
Always allow the temperature to drop and relieve any remaining pressure prior to working to remove any
hydraulic equipment.
RY9212001MBS0004US0
Removing the cab
1. Remove the cab.
(Refer to the chapter Cab Removal and Installation.)
107.9 to 127.4 N·m
Tightening torque Nut (cab) 11.0 to 13.0 kgf·m
79.6 to 94.0 lbf·ft
RY9212166HYS0117US0
Stabilizing the Mini-excavator
1. Position the mini-excavator on hard, level ground, operating the
equipment and blade to lift the body.
DANGER
• Put blocks under the crawler to prevent the mini-excavator
from lowering.
(1) Block
RY9212166HYS0118US0
Removing the step
1. Remove the step and cover.
(1) Step (2) Cover
RY9212166HYS0134US0
Attaching the vacuum pump
1. Attach the breather hose (1) of the hydraulic tank to the vacuum
pump (2), and apply vacuum pressure to the hydraulic tank.
(1) Breather Hose (2) Pneumatic Vacuum Pump
RY9212166HYS0119US0
3-S23 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Removing the hydraulic hoses
1. Remove all the hydraulic hoses on the swivel joint side (inside
the travel frame) and plug or cap the adapters and hoses to
prevent foreign matter from getting into them. Remove the
stopper mounting bolt and the stopper.
IMPORTANT
• Apply a threadlock (Loctite #271).
259.9 to 304.0 N·m
Tightening torque Stopper (2) 26.5 to 31.0 kgf·m
191.7 to 224.2 lbf·ft
(1) Stopper Mounting Bolt (2) Stopper
RY9212166HYS0120US0
Removing the hydraulic hoses
1. Remove the bottom cover of the track frame.
2. Remove all the hydraulic hoses on the body side (inside the
track frame). Plug or cap the adapters and hoses to prevent
foreign matter from getting into them.
RY9212166HYS0121US0
Removing the swivel joint
1. To stop the swivel joint from falling, attach a nylon sling to the
body and suspend.
2. Remove the four swivel joint fixing bolts.
IMPORTANT
• Apply thread lock (Loctite® 271).
166.7 to 196.1 N·m
Tightening torque Swivel joint 17.0 to 20.0 kgf·m
123.0 to 144.6 lbf·ft
3. Turn the swivel joint, remove from the track frame and lower
slowly.
Weight of swivel joint : approx. 28 kg. (62 lbs.)
(1) Bolt (M14 X 45)
RY9212166HYS0122US0
3-S24 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] SWIVEL JOINT
Swivel Joint Exploded View (Standard Spec)
(1) Body
(2) Collar
(3) Packing (U)
(4) O-Ring
(5) Seal
(6) Shaft
(7) Collar
(8) External Circlip
(9) Plug (PT1/4)
(10) Hex Socket Plug
(11) Hex Socket Bolt
(12) Cover (Bottom, RJ)
(13) O-Ring
(14) Bolt (M10x25)
RY9212050HYS0022US0
Swivel joint assembly diagram
1. Packing (U) (3) fitting orientation
Apply grease to the inner and outer surfaces of the packing (U),
and install with the seal lip on the outer side.
2. Tightening torque of screw base (11)
IMPORTANT
• Apply a threadlock (Loctite #271).
196.1 to 225.6 N·m
Tightening torque Hex socket bolt (11) 20.0 to 23.0 kgf·m
144.6 to 166.4 lbf·ft
3. Tightening torque of cover (bottom, RJ) (12) mounting bolt (14)
48.1 to 55.9 N·m
Tightening torque Bolt (14) 4.9 to 5.7 kgf·m
35.5 to 41.2 lbf·ft
Apply threadlock (ThreeBond 1324).
(1) Body (7) Collar
(2) Collar (8) External Circlip
(3) Packing (U) (11) Hex Socket Bolt
(4) O-Ring (12) Cover (Bottom, RJ)
(5) Seal (13) O-Ring
(6) Shaft (14) Bolt (M10 × 25)
RY9212166HYS0030US0
3-S25 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Swivel Joint Exploded View (Angle Spec)
(1) Body
(2) Collar
(3) Packing (U)
(4) O-Ring
(5) Seal
(6) Shaft
(7) Collar
(8) External Circlip
(9) Plug (PT1/4)
(10) Hex Socket Plug
(11) Hex Socket Bolt
(12) Cover (Bottom, RJ)
(13) O-Ring
(14) Bolt (M10x25)
RY9212050HYS0044US0
Swivel Joint ASSY Diagram (Angle Spec)
1. Packing (U) (3) fitting orientation
Apply grease to the inner and outer surfaces of the packing (U),
and install with the seal lip on the outer side.
2. Tightening torque of screw base (11)
IMPORTANT
• Apply a threadlock (Loctite #271).
196.1 to 225.6 N·m
Tightening torque Hex socket bolt (11) 20.0 to 23.0 kgf·m
145 to 165 lbf·ft
3. Tightening torque of cover (bottom, RJ) (12) mounting bolt (14)
48.1 to 55.9 N·m
Tightening torque Bolt (14) 4.9 to 5.7 kgf·m
35.5 to 41.2 lbf·ft
Apply threadlock (ThreeBond 1324).
(1) Body (7) Collar
(2) Collar (8) External Circlip
(3) Packing (U) (11) Hex Socket Bolt
(4) O-Ring (12) Cover (Bottom, RJ)
(5) Seal (13) O-Ring
(6) Shaft (14) Bolt (M10 x 25)
RY9212050HYS0045US0
3-S26 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Swivel Joint Adapter Angles (Standard Spec)
(1) Body Side A: 2-Speed Pilot E: Right Forward (a) 90 °
(2) Shaft Side B: Dozer Lowering F: Left Backward (b) 45 °
(3) Back of Machine C: Dozer Raising G: Right Backward (c) 10 °
(4) Front of Machine D: Left Forward H: Drain
(5) Bolt
IMPORTANT
• Apply a threadlock (Locktite #271).
166.7 to 196.1 N·m
Tightening torque Bolt (5) 17.0 to 20.0 kgf·m
123.0 to 144.6 lbf·ft
RY9212050HYS0023US0
3-S27 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Swivel Joint Adapter Angles (Angle Spec)
(1) Body Side A: 2-Speed Pilot F: Left Backward (a) 90 °
(2) Shaft Side B: Dozer Lowering G: Right Backward (b) 45 °
(3) Back of Machine C: Dozer Raising H: Drain (c) 10 °
(4) Front of Machine D: Left Forward I: Angle Left
(5) Bolt E: Right Forward J: Angle Right
IMPORTANT
• Apply a threadlock (Locktite #271).
166.7 to 196.1 N·m
Tightening torque Bolt (5) 17.0 to 20.0 kgf·m
123.0 to 144.6 lbf·ft
RY9212050HYS0046US0
3-S28 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
5. TRAVEL MOTOR
[1] REMOVAL AND INSTALLATION OF THE TRAVEL MOTOR
CAUTION
• When removing a hydraulic device after operating the machine, lower the bucket and blade to the ground
and turn off the engine.
• Each of the devices and the hydraulic oil are hot and under high pressure immediately after operating the
machine. If the hydraulic oil reached a high operating temperature, it may cause a burn.
• Oil gushing out under pressure has enough force to pierce your skin and may cause you injury.
Always allow the temperature to drop and relieve any remaining pressure prior to working to remove any
hydraulic equipment.
RY9212001MBS0004US0
Removing the travel motor
1. Remove the crawler track. Refer to the chapter Crawler Track
for the removal and installation of the crawler track.
DANGER
• Jack up the mini-excavator with the front-end and the blade
and place timbers under the frame.
RY9212032HYS0082US0
2. Position the swing and swivel as in the photo at left and lower
the bucket and blade to the floor.
RY9212032HYS0083US0
3. Remove the three cover mounting bolts (2) and take the cover
(1) off.
(1) Cover (2) Bolt (M10 × 20)
RY9212001HYS0210US0
4. Connect a vacuum pump to the breather hose of the hydraulic
oil tank and exert negative pressure inside the tank.
Remove the hydraulic hoses (3), (4), (5) and (6).
(3) Hydraulic Hose (5) Hydraulic Hose
(4) Hydraulic Hose (6) Hydraulic Hose
RY9212001HYS0211US0
3-S29 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
5. Temporarily suspend the travel motor with a nylon sling (8) and
remove the nine bolts (7).
IMPORTANT
• Apply a threadlock (Loctite #271).
166.7 to 196.1 N·m
Tightening torque Motor, ASSY (wheel) (1) 17 to 20 kgf·m
123.0 to 144.6 lbf·ft
(7) Bolt (M14)
RY9212166HYS0031US0
6. Hoist and remove the motor and ASSY (wheel) (1) with a crane.
IMPORTANT
• Apply a threadlock (Loctite #271).
166.7 to 196.1 N·m
Tightening torque Sprocket (2) 17 to 20 kgf·m
123.0 to 144.6 lbf·ft
(1) Motor, ASSY (Wheel) (6) Straight Pipe Joint
(2) Sprocket (7) Pipe Joint (S G4, G4)
(3) Bolt (M14) (8) Nylon Sling
(4) Bolt (M14) (9) Spring Washer
(5) Track Frame
RY9212166HYS0032US0
3-S30 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(1) Swivel Joint
(2) Blade Cylinder
(3) Travel Motor L
(4) Travel Motor R
(a) Clamp the 2-Speed Pressure Increase Signal
Hose and the P1 Hose (Right Track Only).
Do Not Come in Contact with the Track Frame.
S/J side Travel motor / cylinder side
A 2-speed pilot L/R travel 2-speed
B lower dozer Cylinder-bottom side
C lift dozer Cylinder-rod side
D left forward Left P1
E right forward right P2
F left reverse left P2
G right reverse right P1
H drain L/R drain port (upper)
RY9212001HYS0214US0
3-S31 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] TRAVEL MOTOR DISASSEMBLY / ASSEMBLY PROCEDURES
(To be continued)
3-S32 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(Continued)
No. Part Name Q'ty No. Part Name Q'ty
(1) Plug 3 (15) Gear (sun) 1
(2) O-Ring 3 (16) Flat head screw 4
(3) O-Ring 1 (17) Plate (thrust) 1
(4) Cover 1 (18) Bearing (inner) 4
(5) Wire 1 (19) Needle bearing 4
(6) Gear case 1 (20) Gear (planetary B) 4
(7) Plug 2 (21) Metal washer 4
(8) Plate, kit (thrust) t = 1.8 mm, 0.07 in. 1 (22) Nut (ring) 1
(8) Plate, kit (thrust) t = 2.3 mm, 0.09 in. 1 (23) Steel ball 99
(8) Plate, kit (thrust) t = 2.8 mm, 0.11 in. 1 (24) Bearing (angular) 1
(9) Gear (drive) 1 (25) Seal 2
(10) Gear (planetary A) 3 (26) Plug 2
(11) Bearing (roller) 3 (27) Flange holder 1
(12) Bearing (inner) 3 (28) O-Ring 3
(13) Thrust washer 3 (29) Spring 1
(14) Holder 1 (30) 2-speed piston 1
(31) Oil seal 1 (61) Plug 1
(32) Ball bearing 1 (62) Plug 2
(33) Ball bearing 1 (63) O-Ring 2
(34) Shaft 1 (64) Spring 2
(35) Ball 2 (65) Spring seat 2
(36) Swash-plate 1 (66) Plug 2
(37) Retainer holder 1 (67) O-Ring 2
(38) Piston ASSY 1 (68) Spring 2
(39) Pin 3 (69) Check valve 2
(40) Retainer plate 1 (70) Orifice 2
(41) Cylinder block 1 (71) Spool 1
(42) Spring seat 1 (72) Spring seat 1
(43) Spring 1 (73) Spring 1
(44) Metal washer 1 (74) Spool C 1
(45) Internal circlip 1 (75) Spool A 1
(46) Disc 1 (76) Plug 1
(47) O-Ring 1 (77) Baseplate 1
(48) Brake piston 1 (78) Hex socket bolt 6
(49) Pin 2 (79) Plug 2
(50) Spring 8 (80) O-Ring 2
(51) Spring 4 (81) Plug 2
(52) O-Ring 1 (82) O-Ring 3
(53) Plate (valve) 1 (83) Plug 2
(54) Ball bearing 1 (84) O-Ring 2
(55) Parallel pin 1 (85) Spring 2
(56) Pin 2 (86) Spring seat 2
(57) Plug 3 (87) Hex socket bolt 3
(58) Orifice 5 (88) Valve body 1
(59) O-Ring 4 (89) Spool 1
(60) Plug 3
RY9212001HYS0310US0
3-S33 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(1) Disassembly Procedures
[A] Gear Case Disassembly
1. Attach the travel motor to the special disassembly platform.
RY9212001HYS0311US0
2. Remove the plug (7).
• Tool to use : M5 hex socket
(7) Plug
RY9212001HYS0312US0
3. Remove the two plugs and replace them with eyebolts, then put
the rod through them.
• Tool to use : M8 hex socket, eyebolts (3/8), rod
(1) Plug
RY9212001HYS0313US0
4. Insert a rod through the housing to keep it from turning.
RY9212001HYS0314US0
5. Turn the eyebolt rod, rotating the cover until you can see the tip
of the wire (5) coming from the plug hole.
Use needle-nose pliers to pull the wire out of the plug hole.
• Tool to use : Needle-nose pliers
(5) Wire
RY9212001HYS0315US0
3-S34 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
6. Pull on the wire (5) while rotating the cover with the rod.
• Tool to use : Pliers
NOTE
• It is easiest to use regular pliers once the wire is out far
enough for them to grasp it. (as regular pliers get a better
grip than needle-nose pliers)
(5) Wire
RY9212001HYS0316US0
7. Remove the eyebolts, attach the cover removal tool and knock
it up to remove the cover.
If a cover removal tool is not available
• Put the rod through the eyebolt holes.
• Knock upwards on both sides of the rod and remove the cover
(4).
• Tool to use : Rod
(4) Cover (d) Cover Removal Tool
RY9212001HYS0317US0
8. Remove the plate and kit (thrust) (8).
(8) Plate, Kit (Thrust)
RY9212001HYS0318US0
3-S35 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
9. Remove the holder and sub-assembly.
Components of the holder and sub-assy
(10) Gear (Planetary A) (13) Thrust Washer
(11) Bearing (Roller) (14) Holder
(12) Bearing (Inner)
RY9212001HYS0319US0
10. Remove the gear (drive) (9).
(9) Gear (Drive)
RY9212001HYS0320US0
11. Remove the gear (sun) (15).
(15) Gear (Sun)
RY9212001HYS0321US0
12. Drain off any gear oil.
If there is not any gear oil, skip this step.
RY9212001HYS0322US0
3-S36 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
13. Remove the flathead screws (16). (4 places)
IMPORTANT
• If the flathead screws are too tight to remove, heat them up
with a heat gun or the like.
• Tool to use : M5 hex socket
(16) Flat Head Screw
RY9212001HYS0323US0
14. Remove the plate (thrust) (17).
(17) Plate (Thrust)
RY9212001HYS0324US0
15. Remove the gear (planetary B) (20).
(20) Gear (Planetary B)
RY9212001HYS0325US0
16. Remove the needle bearing (19).
(19) Needle Bearing
RY9212001HYS0326US0
17. Remove the bearing (inner) (18).
(18) Bearing (Inner)
RY9212001HYS0327US0
3-S37 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
18. Remove the metal washer (21).
(21) Metal Washer
RY9212001HYS0328US0
19. Remove the plug (26). (2 places)
• Tool to use : M8 hex socket
(22) Nut (Ring) (26) Plug
RY9212001HYS0329US0
20. Remove the nut (ring).
(e) Ring Nut Socket
RY9212001HYS0330US0
21. Use removal bolts to raise the gear case up higher than the
flange holder.
IMPORTANT
• Tighten the removal bolts equally.
(6) Gear Case (f) Removal Bolts (M10 × 2.0)
(27) Flange Holder
RY9212001HYS0331US0
22. Remove the gear case from the flange holder.
RY9212166HYS0142US0
3-S38 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
23. Remove the seal (25) from the gear case side.
• Tool to use : Slotted screwdriver
(6) Gear Case (25) Seal
RY9212001HYS0333US0
24. Remove the seal (25) from the flange holder side.
• Tool to use : Slotted screwdriver
(25) Seal (27) Flange Holder
RY9212001HYS0334US0
25. Remove the plug.
• Tool to use : M5 hex socket
(6) Gear Case (7) Plug
RY9212001HYS0335US0
26. Take out the steel balls (23). (99 balls)
IMPORTANT
• Do not lose any of the balls.
• If you fail to remove even one of the balls, the bearing
cannot be removed, so keep close track of the balls.
(6) Gear Case (23) Steel Ball
RY9212001HYS0336US0
27. Remove the bearing (angular) (24) with a press.
(24) Bearing (Angular)
RY9212001HYS0337US0
3-S39 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[B] Motor Disassembly
1. Remove the valve body.
Remove the plug (83), spring (85), spring seat (86) and the
spool (89) in that order.
• Tool to use : M8 hex socket
(83) Plug (86) Spring Seat
(85) Spring (89) Spool
RY9212001HYS0338US0
2. Remove the valve body (88).
IMPORTANT
• Replace O-rings with new ones during reassembly.
• Tool to use : M6 hex socket
Components of the Valve Body ASSY
(82) O-Ring (87) Socket Head Bolt
(83) Plug (88) Valve Body
(85) Spring (89) Spool
(86) Spring Seat
RY9212001HYS0339US0
3. Remove the 2-speed switch.
Remove the plug (60), spring seat (72), spring (73), spool C (74)
and spool A (75) in that order.
IMPORTANT
• Check to make sure there are not any scratches around the
circumference of the spools.
• Tool to use : M8 hex socket, M22 socket wrench
Components of the 2-speed Switch
(60) Plug (74) Spool C
(72) Spring Seat (75) Spool A
(73) Spring (76) Plug
RY9212001HYS0340US0
3-S40 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
4. Remove the counterbalance valve.
Remove the plug (62), spring (64), spring seat (65) and the
spool (71) in that order.
IMPORTANT
• There is little room for the wrench (or socket), so be careful
not to let it slip.
• Check to make sure there are not any scratches around the
circumference of the spools.
• Tool to use : M36 wrench (socket)
(62) Plug (65) Spring Seat
(64) Spring (71) Spool
RY9212001HYS0341US0
5. Remove the hex socket bolt (78).
• Tool to use : M10 hex socket
(77) Baseplate (78) Hex Socket Bolt
RY9212001HYS0342US0
6. Tap the baseplate with a plastic hammer to loosen it.
Once the base plate loosens a bit, insert a slotted screwdriver
in the crack and strike the baseplate from the opposite side and
remove it.
IMPORTANT
• Be very careful because using force to insert a slotted
screwdriver may scratch the baseplate.
RY9212001HYS0343US0
7. Remove the plate (valve) (53) and O-rings (28) and (52).
(28) O-Ring (53) Plate (Valve)
(52) O-Ring (77) Baseplate
RY9212001HYS0344US0
8. Remove the springs (12 springs).
(50) Spring (Large) (51) Spring (Small)
RY9212001HYS0345US0
3-S41 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
9. While pressing down on the piston brake with a rag, blow air
through the brake release oil passage hole (a) and remove the
piston brake.
CAUTION
• Be careful because if you blast air into the passage, the
piston brake may come flying off.
(a) Brake Release Oil Passage Hole (b) 2-Speed Switch Oil Passage Hole
RY9212001HYS0346US0
10. Rotate the disassembly/assembly platform 90 and remove the
disc (46), cylinder block and sub-assembly.
Components of the Cylinder Block and Sub-assy
(37) Retainer Holder (40) Retainer Plate
(38) Piston, ASSY (41) Cylinder Block
(39) Pin (46) Disc
RY9212001HYS0347US0
11. Remove the swash-plate (36).
(36) Swash-Plate
RY9212001HYS0348US0
3-S42 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
12. Turn the disassembly/assembly platform back as it was and
remove the 2-speed piston (30) and the ASSY.
(29) Spring (30) Piston
RY9212001HYS0349US0
13. Remove the ball (35).
(35) Ball
RY9212001HYS0350US0
14. Remove the shaft (34) and ball bearing (33).
(32) Oil Seal (34) Shaft
(33) Ball Bearing
RY9212001HYS0351US0
15. Remove the oil seal.
IMPORTANT
• When you removed the shaft, if the ball bearing had not
been removed, remove them together now.
• Tool to use : Hammer and slotted screwdriver
Enlarged view
RY9212001HYS0352US0
3-S43 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Assembly Procedures
[A] Gear Case Assembly
1. Set the bearing (angular) (26) in the gear case and install it with
a press.
RY9212001HYS0005US0
2. After installing it, check and make sure the groove (a) around
the circumference of the bearing comes right to the center.
(a) Circumference Groove
RY9212001HYS0013US0
3. Put the 99 steel balls (23) inside.
(23) Steel Ball
RY9212001HYS0353US0
4. Wrap the plug (7) with plumber's tape and install it.
6.8 to 8.8 N·m
Tightening torque Plug (7) 0.7 to 0.9 kgf·m
5.0 to 6.5 lbf·ft
• Tool to use : M5 hex socket
(7) Plug
RY9212166HYS0033US0
5. Set the floating seal installation tool (a) on the gear case (6).
(6) Gear Case (a) Floating Seal Installation Tool
Guide (for Housing)
RY9212001HYS0006US0
3-S44 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
6. Apply grease to the O-ring of the seal and install the seal.
RY9212001HYS0007US0
7. Set the seal (25) in the gear case.
(25) Seal
RY9212001HYS0355US0
8. Install the seal in the gear case with the floating seal installation
tool (b).
(b) Floating Seal Installation Tool
(Pusher)
RY9212001HYS0008US0
9. Apply a little gear oil to the sliding surface of the seal.
(4 places, every 90 º)
(1) Seal
RY9212001HYS0356US0
10. Set the holder (flange) on the assembly platform.
Set the floating seal installation tool on the holder (flange).
(c) Floating Seal Installation Tool
Guide (for Flange Holder)
RY9212001HYS0009US0
3-S45 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
11. Apply grease to the O-ring of the seal and install the seal.
RY9212001HYS0010US0
12. Set the seal on the flange holder.
(25) Seal
RY9212001HYS0357US0
13. Install the seal on the holder (flange) with the floating seal
installation tool.
(b) Floating Seal Installation Tool
(Pusher)
RY9212001HYS0011US0
14. Apply a little gear oil on the sliding surface. (4 places, every 90º)
(25) Seal (27) Flange Holder
RY9212001HYS0358US0
15. Install the gear case (6).
(6) Gear Case (27) Flange Holder
RY9212001HYS0359US0
3-S46 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
16. Use clamps to press the gear case onto the holder (flange).
• Tool to use : Clamp
RY9212001HYS0012US0
17. Install the nut (ring).
IMPORTANT
• Make sure the nut (ring) is securely engaged with the flange
holder before removing the clamps.
225.2 to 244.8 N·m
Tightening torque Nut (ring) 23.0 to 25.0 kgf·m
166.1 to 180.6 lbf·ft
(e) Ring Nut Socket
RY9212166HYS0034US0
18. Tap around the outside of the gear case (6) with a hammer.
(4 places, every 90 º)
Rotate the gear case by hand to seat the bearing (angular).
• Tool to use : Plastic hammer
(6) Gear Case
RY9212001HYS0361US0
19. Install the plugs (2) for preventing rotation of the nut (ring).
29.4 to 39.2 N·m
Tightening torque Plug (26) 3.0 to 4.0 kgf·m
21.7 to 28.9 lbf·ft
• Tool to use : M8 hex socket
(22) Nut (Ring) (26) Plug
RY9212166HYS0035US0
20. Swage two places per plug with a punch.
• Tool to use : Hammer and punch
(a) Swage Points
RY9212001HYS0363US0
3-S47 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
21. Install the metal washer (21).
IMPORTANT
• Install with the R face down.
(21) Metal Washer
RY9212001HYS0364US0
22. Install the bearing (inner) (18).
(18) Bearing (Inner)
RY9212001HYS0365US0
23. Install the needle bearing (19).
(19) Needle Bearing
RY9212001HYS0366US0
24. Install the gear (planetary B) (20).
(20) Gear (Planetary B)
RY9212001HYS0367US0
25. Install the plate (thrust) (17).
(17) Plate (Thrust)
RY9212001HYS0368US0
3-S48 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
26. Install the flat head screws (16). (4 places)
Apply loctite to the flat head screws.
19.6 to 29.4 N·m
Tightening torque Flat head screws (16) 2.0 to 3.0 kgf·m
14.5 to 21.7 lbf·ft
• Tool to use : M5 hex socket, Loctite #262
(16) Flat Head Screw
RY9212166HYS0036US0
27. Install the gear (sun) (15).
(15) Gear (Sun)
RY9212001HYS0370US0
28. Install the metal holder (14).
(14) Holder
RY9212001HYS0371US0
29. Install the thrust washer (13).
IMPORTANT
• Install with the R face down.
(13) Thrust Washer
RY9212001HYS0372US0
30. Install the bearing (inner) (12).
(12) Bearing (Inner)
RY9212001HYS0373US0
3-S49 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
31. Install the bearing (roller).
(11) Bearing (Roller)
RY9212001HYS0374US0
32. Install the gear (planetary A) (10).
(10) Gear (Planetary A)
RY9212001HYS0375US0
33. Install the gear (drive) (9).
(9) Gear (Drive)
RY9212001HYS0376US0
34. Measure the distance between the edges of the holder and the
gear case.
This is measurement A (A).
• Tool to use : Depth gauge
RY9212001HYS0377US0
35. Measure the distance between the gear case tooth surface and
the edge of the gear case.
This is measurement B (B).
• Tool to use : Depth gauge
RY9212001HYS0378US0
3-S50 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
36. Subtract measurement B from measurement A to calculate
measurement C.
Select the appropriate plate (thrust, C) to suit measurement C.
Ex.)
23.1 mm (0.909 in.) – 21.5 mm (0.846 in.) = 1.6 mm (0.063 in.)
Measurement C Plate thickness t
0.6 to 1.1 mm 1.8 mm
0.02 to 0.043 in. 0.071 in.
1.2 to1.7 mm 2.3 mm
0.047 to 0.067 in. 0.091 in.
1.8 to 2.3 mm 2.8 mm
0.071 to 0.091 in. 0.094 in.
RY9212001HYS0379US0
37. Install the selected plate and kit (thrust) (8).
(8) Plate, Kit (Thrust)
RY9212001HYS0380US0
38. Install the O-ring (3) on the cover (4).
IMPORTANT
• Apply grease to the O-ring.
• Install so the hole in the gear case aligns with the notched
groove in the cover.
(3) O-Ring (4) Cover
RY9212001HYS0381US0
39. Stop the gear case from rotating.
RY9212001HYS0382US0
40. Bend the last 6 mm (0.2 in.) of a wire 90º and insert the tip of
the wire into the hole in the gear case.
(5) Wire (6) Gear Case
RY9212001HYS0383US0
3-S51 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
41. Rotate the cover with the rod and feed the wire so it is wrapped
all the way around. Cut off any wire protruding from the hole.
• Tool to use : Rod
RY9212001HYS0384US0
42. Install the plug.
6.8 to 8.8 N·m
Tightening torque Plug 0.7 to 0.9 kgf·m
5.0 to 6.5 lbf·ft
• Tool to use : M5 hex socket
(7) Plug
RY9212166HYS0037US0
43. After installing the cover, rotate the assembly platform 90 ° and
pour in gear oil.
Fill it with gear oil until it flows out of the inspection port and then
install the plug.
• Tool to use : M8 hex socket
• Gear oil capacity : 900 cc (2 U.S.gal)
(1) Plug
RY9212001HYS0386US0
[B] Motor Assembly
1. Tap the oil seal in with the oil seal installation tool.
IMPORTANT
• Take care to face the oil seal the right direction.
• Apply grease to its lip and circumference.
(27) Flange Holder (a) Oil Seal Lip
(g) Oil Seal Installation Tool
RY9212001HYS0016US0
3-S52 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
2. Tap the ball bearing in.
IMPORTANT
• Face the ball bearing so the inscription is up.
• Apply grease to the circumference of the ball bearing.
(33) Ball Bearing
RY9212001HYS0387US0
3. Install the two 2-speed pistons (30).
IMPORTANT
• The spring comes out easily, so apply some grease to it.
• Press the piston down and make sure it moves smoothly.
(29) Spring (A) Correct
(30) Piston (B) Incorrect
(32) Ball Bearing
RY9212001HYS0388US0
4. Apply grease to the two balls (35) and install them.
(35) Ball
RY9212001HYS0389US0
5. Install the shaft (34) and then the swash-plate (36).
IMPORTANT
• After installing them, make sure the swash-plate moves
smoothly.
(34) Shaft (36) Swash-Plate
RY9212001HYS0390US0
3-S53 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
6. Install the three pins (39) into the cylinder block (41).
IMPORTANT
• Apply grease to the pins.
(39) Pin (41) Cylinder Block
RY9212001HYS0391US0
7. Install the retainer holder (37).
(37) Retainer Holder
RY9212001HYS0392US0
8. Install the piston ASSY (38) into the retainer plate (40) and then
install it into the cylinder block.
IMPORTANT
• Apply hydraulic oil to the pistons.
• Make sure the pistons move smoothly.
(38) Piston ASSY (40) Retainer Plate
RY9212001HYS0393US0
9. Install the sub-assy of the cylinder block and the disc (46) into
the flange holder.
IMPORTANT
• Turn the disassembly / assembly platform on its side.
(46) Disc
RY9212001HYS0394US0
10. Check and make sure that the cylinder block's sliding surface
sinks below the edge of the holder.
IMPORTANT
• Turn the disassembly / assembly platform on its side.
RY9212001HYS0395US0
3-S54 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
11. Install the brake piston (48).
IMPORTANT
• Apply grease to the O-ring.
(47) O-Ring (52) O-Ring
(48) Brake Piston
RY9212001HYS0396US0
12. Install the eight springs (50).
(50) Spring (Large) (51) Spring (Small)
RY9212001HYS0397US0
13. Install the four springs (51).
(51) Spring (Small)
RY9212001HYS0398US0
14. Install the plate (valve) and O-ring on the base plate.
IMPORTANT
• Take care to install the plate (valve) facing the right
direction.
• Apply grease on the back of the plate (valve) so it does not
fall off the base plate.
• Apply grease to the O-ring.
(28) O-Ring (53) Plate (Valve)
(52) O-Ring (77) Baseplate
RY9212001HYS0399US0
15. Install the base plate (77).
IMPORTANT
• Be careful so the plate (valve) does not fall off.
• Tighten the hex socket bolts in a criss-cross pattern.
121.6 to 135.4 N·m
Tightening torque Hex socket bolt 12.4 to 13.8 kgf·m
89.69 to 99.87 lbf·ft
• Tool to use : M10 hex socket
(77) Baseplate (78) Hex Socket Bolt
RY9212166HYS0038US0
3-S55 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
16. Install the counterbalance unit.
Install the spool (71) and then the spring seat (65).
IMPORTANT
• The spool itself slides smoothly.
• Apply hydraulic oil to the spool.
(65) Spring Seat (71) Spool
RY9212001HYS0401US0
17. Install the two springs (64) and plugs (62).
235 to 245 N·m
Tightening torque Plug (62) 24.0 to 25.0 kgf·m
173 to 181 lbf·ft
• Tool to use : M36 wrench (socket)
(62) Plug (64) Spring
RY9212166HYS0039US0
18. Install spool A (75).
Install spool C (74) in spool A.
IMPORTANT
• The spool itself slides smoothly.
• Apply hydraulic oil to the spool.
(74) Spool C (75) Spool A
RY9212001HYS0403US0
19. Install the spring (73) and spring seat (72).
(72) Spring Seat (73) Spring
RY9212001HYS0404US0
20. Install the two plugs.
49.0 to 58.8 N·m
Tightening torque Plug 5.0 to 6.0 kgf·m
36.1 to 43.4 lbf·ft
• Tool to use : M8 hex socket, M22 socket wrench
(60) Plug (76) Plug
RY9212166HYS0040US0
3-S56 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
21. Components of the 2-speed Switch
(60) Plug (74) Spool C
(72) Spring Seat (75) Spool A
(73) Spring (76) Plug
RY9212001HYS0406US0
22. Install the valve body (88).
IMPORTANT
• Be careful not to forget to install the O-ring.
• Apply grease to the O-ring.
35.0 to 38.8 N·m
Tightening torque Hex socket bolt 3.6 to 4.0 kgf·m
26.0 to 28.6 lbf·ft
• Tool to use : M6 hex socket
(87) Hex Socket Bolt (88) Valve Body
RY9212166HYS0041US0
23. Install the spool (89) and the spring seat (86).
IMPORTANT
• The spool itself slides smoothly.
• Apply hydraulic oil to the spool.
(86) Spring Seat (89) Spool
RY9212001HYS0408US0
24. Install the two springs (85) and plugs (83).
49.0 to 58.8 N·m
Tightening torque Plug (83) 5.0 to 6.0 kgf·m
36.1 to 43.4 lbf·ft
• Tool to use : M8 hex socket
(83) Plug (86) Spring Seat
(85) Spring (89) Spool
RY9212166HYS0042US0
3-S57 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[3] SPECIAL TOOLS
No. in
Name of part
Figure
(a) Floating seal installation tool [Guide (for housing)]
(b) Floating seal installation tool (pusher)
(c) Floating seal installation tool [Guide (for flange holder)]
(d) Cover removal tool
(e) Ring nut socket
(f) Removal bolts (M10 × 2.0)
(g) Oil seal installation tool
RY9212001HYS0410US0
(a) Floating seal installation tool [Guide (for housing)]
A 17 mm (0.67 in.)
B 12 mm (0.47 in.)
C 5 mm (0.2 in.)
D 15 °
E 245 mm (9.65 in.)
F 230 mm (9.06 in.)
G 219.8 mm (8.654 in.)
H 255 mm (10.0 in.)
C1 1 mm (0.04 in.) bevel
a Ra=6.3a
RY9212052HYS0037US0
3-S58 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(b) Floating seal installation tool (pusher)
A 22 mm (0.87 in.)
B 17 mm (0.67 in.)
C 5 mm (0.2 in.)
D 217.5 mm (8.563 in.)
E 215.5 mm (8.484 in.)
F 9.8 mm (0.39 in.)
G 190 mm (7.48 in.)
H 255 mm (10.0 in.)
C1 1 mm (0.04 in.) bevel
a Ra=6.3a
RY9212052HYS0036US0
(c) Floating seal installation tool [Guide (for flange holder)]
A 15 mm (0.59 in.)
B 3 mm (0.1 in.)
C 12 mm (0.47 in.)
D 15 °
E 240 mm (9.45 in.)
F 230.3 mm (9.067 in.)
G 219.8 mm (8.654 in.)
C1 1 mm (0.04 in.) bevel
a Ra=6.3a
RY9212052HYS0038US0
(d) Cover removal tool
A 80 mm (3.1 in.)
B 13 mm (0.51 in.)
C 60 mm (2.4 in.)
D R3/8
E 12.5 mm (0.492 in.)
F M12 x P1.25
G 25 mm (0.98 in.)
H 315 mm (12.4 in.)
C2 2 mm (0.08 in.) bevel
C5 5 mm (0.2 in.) bevel
(1) Tempered
RY9212052HYS0033US0
(e) Ring nut socket
A 12.7 mm (0.50 in.)
B 180 mm (7.09 in.)
C 176 mm (6.93 in.)
D 4 to 16 mm (0.2 to 0.63 in.)
E 90 mm (3.5 in.)
F 10 mm (0.39 in.)
G 107 mm (4.21 in.)
H 9 mm (0.4 in.)
(1) Weld
RY9212052HYS0034US0
3-S59 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(f) Removal bolts (M10 x 2.0)
A M14 x P2.0
B M14 nut
C 250 mm (9.84 in.)
D 5 mm (0.5 in.)
RY9212052HYS0035US0
(g) Oil seal installation tool
A 110 mm (4.33 in.)
B 12 mm (0.47 in.)
C 12 mm (0.47 in.)
D 11 mm (0.43 in.)
E 2 mm (0.08 in.)
F 52 mm (2.0 in.)
G 44 mm (1.7 in.)
H 23.8 mm (0.937 in.)
I 30 °
J 18 mm (0.71 in.)
K 30 mm (1.2 in.)
RY9212052HYS0040US0
3-S60 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
6. HYDRAULIC CYLINDER
[1] HYDRAULIC CYLINDER DISASSEMBLY / ASSEMBLY
PROCEDURES
(1) Cylinder Components
Boom Cylinder
No. Part Name Q'ty No. Part Name Q'ty
(1) Cylinder tube ASSY 1 (12) Cushion seal 1
(2) Piston rod ASSY 1 (13) Collar 1
(3) Cylinder head 1 (14) Backup ring 1
(4) Bushing 1 (15) Cushion bearing 1
(5) U-ring 1 (16) Piston 1
(6) Wiper ring 1 (17) Seal ring ASSY 1
(7) O-Ring 2 (18) Slide ring 2
(8) Backup ring 1 (19) Set screw 1
(9) O-Ring 1 (20) Steel ball 1
(10) Holder 1 (21) Buffer ring 1
(11) Cushion seal 1
RY9212032HYS0030US0
3-S61 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Arm Cylinder
No. Part Name Q'ty No. Part Name Q'ty
(1) Cylinder tube ASSY 1 (14) Backup ring 1
(2) Piston rod ASSY 1 (15) Cushion bearing 1
(3) Cylinder head 1 (16) Piston 1
(4) Bushing 1 (17) Seal ring ASSY 1
(5) U-ring 1 (18) Slide ring 2
(6) Wiper ring 1 (19) Set screw 1
(7) O-Ring 2 (20) Steel ball 1
(8) Backup ring 1 (21) Cushion bearing 1
(9) O-Ring 1 (22) Cushion seal 1
(10) Holder 1 (23) Snap ring 1
(11) Cushion seal 1 (24) Stopper 2
(12) Spacer 1 (25) Snap ring 1
(13) Collar 1 (26) Buffer ring 1
RY9212032HYS0031US0
3-S62 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Disassembly Procedures
Cylinder Disassembly
1. Drain the oil from inside the cylinder, and fasten the cylinder
bottom in a vice across the bolt width.
RY9212032HYS0032US0
2. Place an anti-rotation device in one position of the cylinder head
(3).
(3) Cylinder Head
RY9212032HYS0033US0
3. Use a wrench (hook) or wrench (key) to loosen the cylinder
head (3).
While loosening the cylinder head (3) screw, remove the
cylinder head.
(3) Cylinder Head
RY9212032HYS0034US0
4. Pull out the piston rod assembly (2) together with the cylinder
head (3), and place on a board.
IMPORTANT
• Check whether or not the pipe cap has been removed.
• Provide the port on the cylinder head side with an oil
receptacle.
• Draw the piston rod assembly (2) out horizontally while
keeping it held, to avoid dropping it and causing damage to
parts immediately after it is withdrawn.
(2) Piston Rod ASSY (3) Cylinder Head
RY9212032HYS0035US0
5. Fasten the piston rod assembly (2) in a vice across the bolt
width and use a cushioning material.
IMPORTANT
• Place the rod on a block of wood.
(2) Piston Rod ASSY
RY9212001HYS0431US0
3-S63 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
6. Remove the set screw (19), and remove the steel ball (20).
IMPORTANT
• The set screw (19) is caulked in two locations. Use a hand
drill or similar device to remove the caulking, then loosen
the set screw (19).
• After removing, use a hand tap (M8 × 1.25) to carry off the
piston side.
• If the set screw (19) is damaged on removal, replace it with
a new one.
(19) Set Screw (a) Drill
(20) Steel Ball
RY9212001HYS0432US0
7. Use a wrench (socket wrench) on the hexagonal nut section of
the piston (16), and loosen it.
If a large amount of torque is required, prepare a dynamic
wrench with hydraulic jack - hydraulic cylinder.
(16) Piston
RY9212001HYS0433US0
8. Remove the piston (16), cushion bearing (15) and cylinder head
(3) in that order.
(3) Cylinder Head (15) Cushion Bearing
(10) Holder (16) Piston
RY9212032HYS0036US0
3-S64 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
9. Remove the slide ring (18) by hand, split the seal ring (17) by
tapping it with a flat tip screwdriver (a), and remove.
Remove the O-ring (17) with a spatula.
IMPORTANT
• Do not use seals once removed.
(17) Seal Ring, O-Ring (a) Slotted Screwdriver
(18) Slide Ring
RY9212001HYS0439US0
10. Remove the O-rings (7) (9) and backup ring (8) of the cylinder
head (3).
IMPORTANT
• If removal is difficult, use a screwdriver, taking care not to
damage the cylinder head.
• Do not use seals once removed.
(3) Cylinder Head (8) Backup Ring
(7) O-Ring (9) O-Ring
RY9212032HYS0037US0
11. Remove the wiper ring (6).
The wiper ring (6) is press-fitted.
Use a tool such as a driver, and tap using rubber cushioning.
IMPORTANT
• Do not use seals once removed.
(6) Wiper Ring
RY9212032HYS0038US0
12. Lift the U-ring (5) using a screwdriver, and remove it from the
cylinder head (3).
IMPORTANT
• Do not use seals once removed.
(3) Cylinder Head (5) U-Ring
RY9212032HYS0039US0
13. Lift the buffer ring (21) with a screwdriver, and remove it from
the cylinder head (3).
IMPORTANT
• Do not use seals once removed.
(3) Cylinder Head (21) Buffer Ring
RY9212032HYS0040US0
3-S65 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
14. Lift the snap ring (11) with a screwdriver, and remove it from the
cylinder head (3).
IMPORTANT
• Do not use seals once removed.
(11) Snap Ring
RY9212032HYS0041US0
15. Lightly tap out the bushing (4) with a hammer and chisel, taking
care not to damage the cylinder head (3).
IMPORTANT
• Do not use seals once removed.
(3) Cylinder Head (4) Bushing
RY9212032HYS0042US0
Compression side cushion bearing disassembly (arm cylinder
only)
1. Remove the piston (16).
Disassembly is not possible when the piston (16) is fitted.
(16) Piston
RY9212001HYS0435US0
2. Remove the snap ring (23).
IMPORTANT
• Lightly tap out with a plastic hammer to avoid damaging
the piston rod (2) and cushion bearing (21).
(2) Piston Rod (23) Snap Ring
(21) Cushion Bearing
RY9212001HYS0436US0
3. Slide the cushion bearing (21) to the thread side of the piston
rod (2), and remove the stopper (24) (splits into two).
(2) Piston Rod (24) Stopper
(21) Cushion Bearing
RY9212001HYS0437US0
3-S66 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
4. Remove the cushion bearing (21), and remove the cushion seal
(22).
The cushion seal (22) has a split opening in one location, so
widen the split to remove.
(2) Piston Rod (23) Snap Ring
(21) Cushion Bearing (24) Stopper
(22) Cushion Seal
RY9212001HYS0438US0
(3) Assembly Procedures
Precautions on Assembly
Replacing Seals
All seals must be replaced when disassembling the cylinder.
Replacing O-rings
Thoroughly clean the mounting groove before fitting the backup ring and O-ring.
Take care over the backup ring location.
Apply grease or hydraulic fluid to the backup ring and O-ring, for smoothness of assembly.
If not sufficiently lubricated, O-rings may become twisted during assembly, resulting in oil leakage.
RY9212001HYS0444US0
Cylinder Head Assembly
1. Use press-fitting tool (A) to press-fit the bushing (4).
IMPORTANT
• Apply hydraulic fluid beforehand to the cylinder head inner
surface.
Also check that there is no unevenness due to scratching,
etc., of the bushing after press fitting.
(3) Cylinder Head (A) Tool
(4) Bushing
RY9212032HYS0043US0
Snap ring assembly
1. Insert the snap ring (11) as far as the cylinder head (3) mounting
groove using the press-fitting tool (B).
(3) Cylinder Head (B) Tool (Spatula, etc.)
(11) Snap Ring
RY9212032HYS0044US0
3-S67 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
U-ring and buffer ring assembly
1. Apply hydraulic fluid to the buffer ring (21) and U-ring (5), install
in the cylinder head (3), and use assembly tool (C) to insert as
far as the used mounting groove.
IMPORTANT
• Make sure the buffer ring (21) and U-ring (5) are installed
with the correct orientation.
• Place the buffer ring (21) and U-ring (5) in hot water
[approx. 90 °C (194 °F)] for about five to ten minutes to
soften them prior to installation.
(3) Cylinder Head (C) Tool
(5) U-Ring
(21) Buffer Ring
RY9212032HYS0045US0
Wiper ring assembly
1. Apply hydraulic fluid to the wiper ring (6).
Place the tool (D) on the wiper ring (6), and use a press to insert
it.
(3) Cylinder Head (D) Tool
(6) Wiper Ring
RY9212032HYS0046US0
Seal assembly
1. Apply hydraulic fluid to the O-rings (7) (9) and backup ring (8)
and install in the cylinder head (3).
(4) Bushing (8) Backup Ring
(5) U-Ring (9) O-Ring
(6) Wiper Ring (21) Buffer Ring
(7) O-Ring
RY9212032HYS0047US0
Piston assembly
1. Install the O-ring (17) for the seal ring assembly.
Apply hydraulic fluid to the O-ring (17).
(16) Piston (17) O-Ring
RY9212001HYS0450US0
3-S68 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
2. Quickly install the seal ring (17) for the sealing assembly using
the tools (E) (F).
(16) Piston (E) Tool
(17) Seal Ring, O-Ring (F) Tool
RY9212001HYS0451US0
3. After installing the seal ring assembly, quickly pass through the
correcting tool (G) for correction.
(G) Tool
RY9212001HYS0452US0
4. To facilitate installation of the two slide rings (18), first roll them
tight (see photo) before installing.
(16) Piston (18) Slide Ring
RY9212001HYS0453US0
Piston rod assembly
1. Fasten the piston rod (2) in a vice, apply hydraulic fluid to the
seal section of the cylinder head (3), and install the piston rod.
IMPORTANT
• Take care so that the lip of the wiper ring and U-ring does
not catch on the stepped section.
(2) Piston Rod (3) Cylinder Head
RY9212032HYS0048US0
3-S69 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
2. Fit the holder (10) and cushion bearing (15), to which hydraulic
fluid has been applied, to the piston rod (2). (In the case of the
boom cylinder)
IMPORTANT
• Take care over the installation orientation of the cushion
bearing (15).
(2) Piston Rod (15) Cushion Bearing
(10) Holder
RY9212032HYS0049US0
3. Fit the piston (16) to the piston rod (2).
(2) Piston Rod (16) Piston
RY9212001HYS0456US0
4. Tighten the piston (16).
IMPORTANT
• Tighten the piston to the specified torque.
(16) Piston
RY9212001HYS0461US0
5. Insert the steel ball (20) in the piston (16).
(16) Piston (20) Steel Ball
RY9212001HYS0462US0
6. Tighten the set screw (19).
(19) Set Screw
RY9212001HYS0463US0
3-S70 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
7. Use a punch to caulk in two locations on the circumference of
the piston (16).
(16) Piston a : Punch
(19) Set Screw b : Caulking
(20) Steel Ball
RY9212001HYS0464US0
8. Hold the cylinder tube (1) horizontally in a vice, and insert the
piston rod (2) to which hydraulic fluid has been applied.
(1) Cylinder Tube (2) Piston Rod
RY9212032HYS0050US0
9. Use a wrench (hook) or wrench (key) to tighten the cylinder
head (3).
(3) Cylinder Head
RY9212032HYS0051US0
10. Firmly bend the lock washer into the cylinder head groove.
RY9212032HYS0052US0
3-S71 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Compression side cushion bearing disassembly (arm cylinder only)
Fit the cushion bearing before fitting the piston nut. Assembly is not possible if the nut is already fitted.
1. Insert the cushion seal (22) in the groove with the slit towards
the thread side.
(22) Cushion Seal
RY9212001HYS0457US0
2. Assemble the cushion bearing (21) paying attention to the
machined flat part.
(21) Cushion Bearing
RY9212001HYS0458US0
3. Insert the stopper (24) in the groove.
(24) Stopper
RY9212001HYS0459US0
4. Push the cushion bearing (21) fully in the direction of the
stopper (24), and tap in the snap ring (23).
IMPORTANT
• Lightly tap the rod and cushion bearing with a plastic
hammer.
(2) Piston Rod (23) Snap Ring
(21) Cushion Bearing (24) Stopper
(22) Cushion Seal
RY9212001HYS0460US0
3-S72 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Cylinder Inspection
1. Warping of the piston rod
1. Put the piston rod by itself on the V blocks.
2. Set a dial gauge on the center of the rod.
3. Rotate the piston rod and read the measurements on the dial
gauge. Warpage equals 1/2 the difference in the readings.
4. Replace any rod that exceeds its usage limit.
• Factory spec for warpage : 0.05 mm (0.002 in.) ≥
• Usage limit for warpage : 0.5 mm (0.02 in.)
2. Wear in the rod and bushings
1. Measure the diameter of the outside of the piston rod and that
of the inside of the bushing in the cylinder head and calculate
the gap.
Rod size Gap
25 to 40 mm 0.25 mm ≥
0.99 to 1.50 in. 0.01 in. ≥
Factory specification
45 to 75mm 0.30 mm ≥
1.8 to 3.0 in. 0.01 in. ≥
25 to 40 mm 0.4 mm
0.99 to 1.50 in. 0.02 in.
Allowable limits
45 to 75 mm 0.5 mm
1.8 to 3.0 in. 0.02 in.
3. Wear in the tube and piston ring
1. Measure the inside diameter of the cylinder tube.
2. Measure the outside diameter of the piston ring and calculate
the clearance.
Rod size Gap
60 mm ≥ 0.05 to 0.30 mm
2.4 in. ≥ 0.002 to 0.010 in.
65 to 115 mm 0.05 to 0.35 mm
Factory specification
2.60 to 4.53 in. 0.002 to 0.010 in.
120 mm ≤ 0.05 to 0.40 mm
4.72 in. ≤ 0.002 to 0.020 in.
60 mm ≥ 0.60 mm
2.4 in. ≥ 0.02 in.
65 to 115 mm 0.70 mm
Allowable limits
2.60 to 4.53 in. 0.03 in.
120 mm ≤ 0.80 mm
4.72 in. ≤ 0.03 in.
RY9212166HYS0043US0
3-S73 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
7. PILOT VALVE (CONTROL)
[1] PILOT VALVE (CONTROL) ASSEMBLY
Used parts of pilot valve hydraulic hose
Left P/V
Used part Hose tape color
1 Swivel left Gray
2 Arm dump Black
3 Swivel right Light blue
4 Arm crowd Blue
P1 P port 66666666
P2 P port –
T T port 55555555
Right P/V
Used part Hose tape color
1 Bucket crowd White
2 Boom down Yellow
3 Bucket dump Red
4 Boom up Green
P1 P port 44444444
P2 P port –
T T port 33333333
(a) P1 Port
(b) Port 3
(c) Port 2
(d) T Port
(e) Port 1
(f) Port 4
(g) P2 Port
(h) 15 °
(i) 30 °
(A) Left
(B) Right
RY9212166HYS0123US0
3-S74 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] PILOT VALVE (CONTROL) DISASSEMBLY / ASSEMBLY
PROCEDURES
(1) Pilot Valve Components
No. Part Name Q'ty
(1) Casing 1
(2) Plate 1
(3) Spool 4
(4) Plug 4
(5) Pushrod 2
(6) Pushrod 2
(7) Seal 4
(8) O-Ring 4
(9) Spring seat 2
(10) Spring seat 2
(11) Washer 2 4
(12) Spring (Ports 1 and 3) 2
(13) Spring (Port 2) 1
(14) Spring (Port 4) 1
(15) Spring 2
(16) Spring 2
(17) Joint 1
(18) Round plate 1
(19) Adjusting nut 1
(20) Lock nut 1
(21) Lever 1
(22) Handle 1
(23) Spring Pins 1
(24) Boot 1
RY9212032HYS0056US0
(2) Disassembly
Disassembly Procedures
CAUTION
• All of the parts are precisely made, so be very careful in handling them and taking care not to drop or hit
parts against each other.
• If you hit a part too hard while working on it, it may result in burrs or other damage, thus preventing
installation as well as oil leaks and/or compromised performance, so be careful when handling parts.
• If parts are left disassembled or left partway disassembled, humidity or foreign matter may cause rust, so
if interrupting the work is unavoidable, take precautions to protect the parts from rust and dust.
RY9212001HYS0476US0
1. Clamp the pilot valve in a vise.
IMPORTANT
• When clamping it in a vise, use a sheet of copper to prevent
scratching the pilot valve.
(1) Casing (19) Nut (Adjustment)
(18) Nut (Disc)
RY9212182HYS0192US0
3-S75 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
2. Use two wrenches on the nuts (adjustment and disc) to remove
them.
• Tools to use : 22 mm and 32 mm (0.87 in. and 1.3 in.) wrenches
(19) Nut (Adjustment)
RY9212182HYS0176US0
3. Mark the alignment of holes to the casing.
RY9212001HYS0479US0
4. After mounting tool (B) on the U-joint, use tool (A) to turn the
U-joint counterclockwise and loosen it.
CAUTION
• When removing the U-joint, take care that it does not pop
off.
(17) U-Joint (A) Tool
(B) Tools (2)
RY9212182HYS0193US0
3-S76 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
5. Remove the plate.
(2) Plate
RY9212001HYS0481US0
6. Slip a slotted screwdriver in the groove in the plug to remove the
plug.
CAUTION
• Take care so the plug does not go flying.
• Take care not to damage it by exerting force unevenly.
• If a burr is formed, use a whetstone to remove it.
(4) Plug
RY9212182HYS0194US0
7. Remove the reducing valve ASSY (a) and the return spring.
IMPORTANT
• Tag the springs to positively ID which port they go to.
(12) Spring (a) Reducing Valve ASSY
(13) Spring
(14) Spring
RY9212182HYS0195US0
3-S77 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
8. To disassemble the reducing valve, press the spring seat in and
while compressing the secondary pressure spring, shift the
spring seat to the side and remove it from the spool via the
larger hole.
IMPORTANT
• Be careful not to scratch the surface of the spool.
• Do not depress the spring seat 6.0 mm (0.2 in.) ≤.
• Do not disassemble the reducing valve unless there is a
problem with it.
Components of the Reducing Valve
(3) Spool (11) Metal Washer 2
(9) Spring Seat (13) Spring
(10) Spring Seat
RY9212182HYS0177US0
9. Remove the plug from the pushrod.
(4) Plug (6) Pushrod
(5) Pushrod (8) O-Ring
RY9212182HYS0196US0
10. Remove the O-ring and seal from the plug.
IMPORTANT
• Use a mini slotted screwdriver.
• Be careful not to scratch the inside surface of the plug.
Components of the Plug
(4) Plug (7) Seal
(6) Pushrod (8) O-Ring
RY9212182HYS0197US0
3-S78 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Assembly
Assembly Procedures
CAUTION
• Prepare your workbench in the same way as for disassembly.
• Follow the same general precautions as in the disassembly.
• When assembling the parts, remove all bits of metal or foreign matter from all the parts and make sure
there aren't any burrs or dings on the parts.
• Replace used O-rings with new ones.
• Take care not to damage the O-rings when installing them.
RY9212001HYS0001US0
1. Make sure there aren't any burrs or scratches inside the casing.
RY9212001HYS0487US0
2. Install the return spring in the casing.
IMPORTANT
• Install it in the same position as before disassembly.
(12) Spring (14) Spring
(13) Spring
RY9212182HYS0198US0
3. Install the metal washer, spring and spring sea in order to the
spool.
IMPORTANT
• Do not depress the spring seat 6.0 mm (0.2 in.) or more.
• Be careful not to scratch the spool.
(3) Spool (11) Metal Washer 2
(9) Spring Seat (13) Spring
(10) Spring Seat
RY9212182HYS0178US0
4. Install the reducing valve ASSY.
After installing it, make sure the spool moves smoothly.
IMPORTANT
• Install it in the same position as before disassembly.
RY9212001HYS0490US0
3-S79 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
5. Install the O-ring on the plug.
(4) Plug (8) O-Ring
RY9212182HYS0199US0
6. Install the seal on the plug.
IMPORTANT
• Be careful that the seal faces the right direction.
• Apply hydraulic oil on the circumference and lip of the seal.
(4) Plug (7) Seal
(5) Pushrod (8) O-Ring
(6) Pushrod
RY9212182HYS0200US0
7. Install the plug on the pushrod.
IMPORTANT
• Apply hydraulic oil to the pushrod.
(4) Plug (6) Pushrod
(5) Pushrod (8) O-Ring
RY9212182HYS0201US0
8. Install the plug ASSY into the case.
If the return spring is too stiff, use the plate to install the ASSY.
IMPORTANT
• Make sure not to scratch the hole of the case.
• Take care so the plug ASSY does not pop out.
RY9212001HYS0494US0
3-S80 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
9. Install the plate.
(2) Plate
RY9212001HYS0495US0
10. Install the U-joint.
44 to 50 N·m
Tightening torque U-joint 4.5 to 5.1 kgf·m
32.5 to 36.8 lbf·ft
(A) Tool
RY9212182HYS0179US0
11. Install the nut (disc) on the universal joint.
Tighten it until it touches all four pushrods equally.
CAUTION
• If you tighten it too far, the mechanism will not function
properly when the lever is in neutral, so be careful to adjust
the nut to the correct position.
(18) Nut (Disc)
RY9212182HYS0202US0
12. Tighten the nut (adjustment).
Put the wrench on the bolt width of the disc and tighten the nut.
• Tools to use : 22 mm (0.87 in.) wrench (or socket), 32 mm
(1.3 in.) wrench
63.7 to 73.5 N·m
Tightening torque Nut (adjustment) 6.5 to 7.5 kgf·m
47.0 to 54.2 lbf·ft
RY9212182HYS0180US0
13. Apply grease to the rotating parts of the universal joint and to the
ends of the pushrods.
RY9212001HYS0499US0
3-S81 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(4) U-Joint Tightening Tool
A 29 mm ( 1.142 in.)
B 26.5 mm ( 1.043 in.)
C 23.5 mm (0.925 in.) (nut width)
D 19 mm ( 0.748 in.)
E 13 mm (0.512 in.)
F 69 mm (2.717 in.)
G 54 mm (2.126 in.)
H 50 mm (1.968 in.)
I 46 mm (1.811 in.)
J 25 mm (0.984 in.)
K 17 mm (0.669 in.)
L 23 mm ( 0.906 in.)
M 27 mm ( 1.063 in.)
N 31 mm ( 1.220 in.)
O Hole H 6 mm (0.236 in.)
P Axle n 6 mm (0.236 in.)
Q 16 mm ( 0.6299 in.)
R 15.5 mm (0.6102 in.)
S 0.5 × 15 mm (0.0197 × 0.591 in.)
T 12.5 mm (0.492 in.)
U 9.5 mm (0.374 in.)
V 11.6 mm (0.457 in.)
W 6.5 mm (0.256 in.)
C1 0.5 mm (0.0197 in.) bevel
R1 R 13 mm (0.512 in.)
R2 R 5.8 mm (0.228 in.)
R3 R 4.5 mm (0.177 in.)
(1) Bushing (a) U-Joint Tightening Tool, Detailed
Schematic
(b) Bushing, Detailed Schematic
(c) Assembled U-Joint
RY9212166HYS0049US0
3-S82 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
8. PILOT VALVE (TRAVEL)
Pilot Valve (Travel) Exploded View
(1) Valve Assembly (PV, Travel)
(2) Pipe Joint (S, G2, G2)
(3) Filter
(4) Pipe Joint (L, G1/4-G3/8)
(5) Pipe Joint (T, G2, G2-G2)
(6) Adapter
(7) Pressure Sensor
(8) Pedal Assembly (Travel Left)
(9) Pedal (Travel 2)
(10) Pedal Assembly (Travel Right)
(11) Headed Pin
(12) Flat Metal Washer
(13) Snap Pin
(14) Bolt (M10 × 25)
(15) Bolt (M10 × 25)
(16) Lever (Travel, Right)
(17) Lever (Travel, Left)
(18) Bolt (M8 × 20)
(19) Snap Pin 8
(20) Flat Metal Washer
(21) Headed Pin
(22) Damper (HST)
48.1 to 55.9 N·m
Bolt (15) 4.9 to 5.7 kgf·m
35.5 to 41.2 lbf·ft
17.7 to 20.6 N·m
Tightening
Bolt (18) 1.8 to 2.1 kgf·m
torque
13.0 to 15.2 lbf·ft
30.0 to 34.0 N·m
Pressure
3.1 to 3.5 kgf·m
sensor (7)
22 to 25 lbf·ft
RY9212166HYS0124US0
(1) Travel Pilot Valve, Assy
(2) Pipe Joint (S, G1/4-8.4)
(3) Filter Assy.
(4) Pipe Joint (L, G1/4-G3/8)
(5) Pipe Joint (T, G2, G2-G2)
(6) Adapter
(7) Pressure Sensor
RY9212166HYS0125US0
3-S83 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[1] PILOT VALVE (TRAVEL) ASSEMBLY
No. Name of part No. Name of part No. Name of part
(1) Shim (t = 0.1 mm, 0.04 in.) (12) Cover (23) Hex set screw
(2) Shim (t = 0.2 mm, 0.08 in.) (13) Cam (24) Flat metal washer
(3) Seat (14) Spring (25) Rivet screw
(4) Sleeve (15) Spring (26) Parallel pin
(5) Pusher (16) Collar (27) Ball
(6) Pin (17) Bushing (28) O-Ring
(7) Nameplate (18) Plug (29) O-Ring
(8) Shim (t = 0.2 mm, 0.08 in.) (19) Collar (30) O-Ring
(9) Shim (t = 0.1 mm, 0.04 in.) (20) Flanged plug (31) O-Ring
(10) Spool (21) Hex socket bolt (32) Expander
(11) Body (22) Hex socket bolt (33) Pusher ASSY
RY9212001HYS0503US0
3-S84 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] PILOT VALVE (TRAVEL) DISASSEMBLY / ASSEMBLY
PROCEDURES
(1) Disassembly Procedures
1. Remove the boot.
(17) Bushing
RY9212001HYS0504US0
2. Remove the two hex socket set screws.
CAUTION
• Note that there are two hex set screws per hole.
• Tool to use : M3 hex socket
(23) Hex Set Screw
RY9212001HYS0505US0
3. Remove the pin.
• Tool to use : Hammer and pin punch
(6) Pin (12) Cover
RY9212001HYS0506US0
4. Remove the cam.
(13) Cam
RY9212001HYS0507US0
5. Remove the hex socket bolt.
• Tool to use : M8 hex socket
(22) Hex Socket Bolt
RY9212001HYS0508US0
3-S85 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
6. Remove the cover.
(12) Cover
RY9212001HYS0509US0
7. Remove the pusher ASSY.
IMPORTANT
• There is a shim on the edge of the pusher ASSY.
• If it comes off, return it to the top of the sleeve.
(12) Cover (33) Pusher ASSY
RY9212001HYS0510US0
8. Remove the O-rings (25).
• Tool to use : Slotted screwdriver
(25) O-Ring
RY9212001HYS0511US0
9. Mark the positioning of the body hole and the spool ASSY.
RY9212001HYS0512US0
10. Spool ASSY from the body (a) Remove the spring.
(11) Body (a) Spool ASSY
(15) Spring
RY9212001HYS0513US0
3-S86 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
11. Remove the O-ring from the body.
(11) Body (30) O-Ring
RY9212001HYS0514US0
12. Remove the shim.
(1) Shim
RY9212001HYS0515US0
13. Clamp the spool in a vice and remove the hex socket bolt.
IMPORTANT
• Use a copper plate in the vice to prevent it from scratching
the spool.
• Be careful not to overtighten the vice as this will deform the
spool.
• Tool to use : M3 hex socket
(21) Hex Socket Bolt
RY9212001HYS0516US0
Components of the Spool ASSY
(1) Shim (14) Spring
(4) Sleeve (16) Collar
(8) Shim (21) Hex Socket Bolt
(10) Spool (24) Flat Metal Washer
RY9212001HYS0517US0
14. Remove the flanged plug.
• Tool to use : M6 hex socket
(11) Body (20) Flanged Plug
RY9212001HYS0518US0
3-S87 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
15. Remove the seat.
• Tool to use : M5 hex socket
(3) Seat
RY9212001HYS0519US0
16. Remove the ball.
• Tool to use : Magnet
(27) Ball
RY9212001HYS0520US0
3-S88 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Assembly Procedures
1. Insert the ball in the body.
(11) Body (27) Ball
RY9212001HYS0521US0
2. Apply Loctite to the threads of the seat.
• Tool to use : Loctite 262
(3) Seat
RY9212001HYS0522US0
3. Install the seat.
14.7 N·m
Tightening torque Seat (3) 1.5 kgf·m
10.8 lbf·ft
• Tool to use : M5 hex socket
RY9212166HYS0050US0
4. Install the flanged plug (20).
24.5 N·m
Tightening torque Flanged plug (20) 2.5 kgf·m
18.1 lbf·ft
• Tool to use : M6 hex socket
(20) Flanged Plug
RY9212166HYS0051US0
5. Clamp the spool in a vice and install the flat metal washer.
IMPORTANT
• Be careful to follow the order of installation.
• Use a copper plate in the vice to prevent it from scratching
the spool.
• Be careful not to overtighten the vice as this will deform the
spool.
(10) Spool (24) Flat Metal Washer
RY9212001HYS0525US0
3-S89 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
6. Install the shim.
IMPORTANT
• Be careful to follow the order of installation.
(8) Shim
RY9212001HYS0526US0
7. Install the spring.
IMPORTANT
• Be careful to follow the order of installation.
(14) Spring
RY9212001HYS0527US0
8. Install the sleeve.
IMPORTANT
• Be careful to follow the order of installation.
(4) Sleeve
RY9212001HYS0528US0
9. Install the collar.
IMPORTANT
• Be careful to follow the order of installation.
(16) Collar
RY9212001HYS0529US0
10. Apply Loctite to the threads of hex socket bolt.
• Thread locking compound (Loctite 242)
(21) Hex Socket Bolt
RY9212001HYS0530US0
3-S90 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
11. Install the hex socket bolt (21).
4.9 N·m
Tightening torque Hex socket bolt (21) 0.5 kgf·m
3.6 lbf·ft
• Tool to use : M3 hex socket
(21) Hex Socket Bolt
RY9212166HYS0084US0
12. Install the shim.
IMPORTANT
• Install the same number of shims as were disassembled.
(1) Shim (4) Sleeve
RY9212001HYS0532US0
13. Install the O-ring.
(11) Body (30) O-Ring
RY9212001HYS0533US0
14. Install the spring.
(15) Spring
RY9212001HYS0534US0
15. Install the spool ASSY (a).
IMPORTANT
• Install in the same holes in the body as during
disassembly.
(11) Body (a) Spool ASSY
(15) Spring
RY9212001HYS0535US0
3-S91 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
16. Install the O-ring in the cover.
(28) O-Ring
RY9212001HYS0536US0
17. Install the pusher ASSY.
(12) Cover (33) Pusher ASSY
RY9212001HYS0537US0
18. Install the cover (12).
22.6 N·m
Tightening torque Cover (12) 2.3 kgf·m
16.7 lbf·ft
• Tool to use : M8 hex socket
(12) Cover (22) Hex Socket Bolt
RY9212166HYS0052US0
19. Apply grease to the pusher ASSY balls.
(33) Pusher ASSY
RY9212001HYS0539US0
20. Apply grease to the sliding part of the pin and install it.
(6) Pin (13) Cam
(12) Cover
RY9212001HYS0540US0
3-S92 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
21. Install the hex socket set screws (23).
IMPORTANT
• Note that each one has two hex socket set screws (23).
9.8 N·m
Tightening torque Hex set screw (23) 1.0 kgf·m
7.2 lbf·ft
• Tool to use : M3 hex socket
(23) Hex Set Screw
RY9212166HYS0053US0
22. Install the boot.
(17) Bushing
RY9212001HYS0542US0
NOTE
• Use shims (1), (2), (8) or (9) as needed.
It is not a problem if there are no shims at all or a lot of
shims.
• Shims are used as needed, so be sure to install them where
there were used before.
RY9212001HYS0543US0
3-S93 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
9. PILOT VALVE (SWING)
No. Part Name Q'ty
(1) Bellows 1
(2) Hex socket bolt 1
(3) Ball 2
(4) Cam 1
(5) Bushing 2
(6) Cam shaft 1
(7) Spring (return) 2
(8) Spring (secondary pressure) 2
(9) Metal washer 2
(10) Spring seat 2
(11) Spool 2
(12) Hex socket bolt 2
(13) O-Ring 1
(14) RO plug 1
(15) Shim 2
(16) Pushrod 2
(17) O-Ring 2
(18) Gasket 2
(19) Plug 2
(20) Cover 1
(21) Casing 1
RY9212001HYS0550US0
[1] PILOT VALVE (SWING) DISASSEMBLY
1. Clamp the swing valve in a vise.
2. Remove the bellows (1) from the cover (20).
IMPORTANT
• Use a copper plate when clamping the part.
(1) Bellows (20) Cover
RY9212050HYS0042US0
3. Remove the hex socket bolt (2).
IMPORTANT
• Note that Loctite was used so loosening will require a lot of
force.
• Tool to use : M3 hex socket
RY9212001HYS0552US0
3-S94 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
4. Put a pin punch against the edge of the cam shaft (6) and tap it
lightly with a hammer to remove it.
• Tool to use : Hammer and pin punch [ 7 mm, ( 0.3 in.) ≥]
(6) Cam Shaft
RY9212166HYS0054US0
5. Remove the cam (4).
IMPORTANT
• Handle the cam (4) and the ball (3) as an assembly.
(Cannot be disassembled)
• Mark the relationship between the cam (4) and the cover.
(3) Ball (4) Cam
RY9212001HYS0554US0
6. Remove the hex socket bolt.
• Tool to use : M5 hex socket
RY9212001HYS0555US0
7. Remove the cover (20).
CAUTION
• Mark the relationship between the cover (20) and the casing
(21).
• Be careful so the pushrod (16) and the plug (19) don't pop
out.
(7) Spring (Return) (19) Plug
(16) Pushrod (20) Cover
(17) O-Ring (21) Casing
RY9212001HYS0556US0
3-S95 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
8. Remove the plug (19).
IMPORTANT
• Mark the relationship between the plug (19) and the casing
(21).
(16) Pushrod (19) Plug
(17) O-Ring
RY9212001HYS0557US0
9. Remove the reducing valve ASSY A and the spring (7) from the
casing.
IMPORTANT
• Mark the relationship of the casing holes.
(7) Spring (Return) A : Reducing Valve ASSY
(8) Spring (Secondary Pressure)
RY9212001HYS0558US0
10. Put the cover (20) on its side, put a pin punch against the
bushing (5) and lightly tap it with a hammer to remove it.
• Tools to use : Hammer and pin punch [ 10 mm, ( 0.39 in.) ≥]
(5) Bushing (20) Cover
RY9212166HYS0055US0
11. To disassemble the reducing valve, compress the spring, shift
the spring seat (10) to the side and remove the spool via the
large hole.
IMPORTANT
• Be careful not to scratch the spool.
• Do not depress the spring seat 4 mm (0.2 in.) ≤
• Do not disassemble the reducing valve unless there is a
problem with it.
(10) Spring Seat
RY9212166HYS0056US0
3-S96 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
12. Remove the spool (11), secondary pressure setting spring (8),
shims (15) and metal washer (9).
IMPORTANT
• Treat as an assembly until reassembly.
• The thickness of the metal washers is different for each
spool ASSY due to the preset adjustment of the secondary
pressure setting spring (8).
• A metal washer (9) is not used in the figure.
(8) Spring (Secondary Pressure) (11) Spool
(10) Spring Seat (15) Shim
RY9212001HYS0561US0
13. Remove the plug (19) from the pushrod (16).
(16) Pushrod (19) Plug
RY9212001HYS0562US0
14. Remove the gasket (18) from the plug (19).
CAUTION
• Use a mini slotted screwdriver to remove it.
• Be careful not to scratch the inside surface of the plug.
• Tool to use : Slotted screwdriver
(18) Gasket (19) Plug
RY9212001HYS0563US0
15. Remove the O-ring (17) from the plug (19).
(17) O-Ring (19) Plug
RY9212001HYS0564US0
[2] PILOT VALVE (SWING) ASSEMBLY
1. Install the metal washer, shim (15), secondary pressure setting
spring (8) and spring seat (10) in order to the spool (11).
IMPORTANT
• The thickness of the metal washers is different for each
spool ASSY due to the preset adjustment of the secondary
pressure setting spring (8).
(8) Spring (Secondary Pressure) (11) Spool
(10) Spring Seat (15) Shim
RY9212001HYS0565US0
3-S97 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
2. Pass the end of the spool through the larger part of the hole in
the spring seat (10), compressing the spring and shifting the
spring seat to the side to install it.
IMPORTANT
• Be careful not to scratch the spool.
• Do not depress the spring seat 4 mm (0.2 in.) ≤
(10) Spring Seat
RY9212166HYS0057US0
3. Clamp the casing (21) in a vise. Install the spring (7) in the
casing (21).
IMPORTANT
• Install it in the same position as before disassembly.
(7) Spring (Return) (21) Casing
RY9212001HYS0567US0
4. Install the reducing valve ASSY A to the casing (21).
IMPORTANT
• Install it in the same position as before disassembly.
• When installing the reducing valve ASSY, take care not to
hit the bottom edge of the spool hard against the corner B
or the casing.
(21) Casing A : Reducing Valve ASSY
B : Corner of Casing
RY9212001HYS0568US0
5. Install the O-ring (19) on the plug (17).
IMPORTANT
• Apply hydraulic oil to the O-ring.
(17) O-Ring (19) Plug
RY9212001HYS0569US0
3-S98 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
6. Install the gasket (18) on the plug (19).
IMPORTANT
• Be careful that the gasket faces the right direction.
(The gasket (18) has an uneven shape ; put the end with a
larger diameter in first.)
• Apply hydraulic oil on the circumference and lip of the
gasket.
(18) Gasket (19) Plug
RY9212001HYS0570US0
7. Install the pushrod (16) into the plug (19).
IMPORTANT
• Apply hydraulic oil to the pushrod (16).
• Do not force the gasket (18) in as it may damage its lip.
(16) Pushrod (19) Plug
RY9212001HYS0571US0
8. Install the pushrod and plug ASSY in the casing (21).
(19) Plug (21) Casing
RY9212001HYS0572US0
9. Turn the cover on its side and tap lightly on the bushing (5) with
a hammer to install it.
IMPORTANT
• Take care not to knock the bushing so it sticks out from the
inside of the cover.
• Tool to use : hammer
(5) Bushing
RY9212001HYS0573US0
3-S99 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
10. Install the cover (20) on the casing (21).
IMPORTANT
• Install it in the same position as before disassembly.
• Note that the cover will ride up due to the springs.
(20) Cover (21) Casing
RY9212001HYS0574US0
11. Install the hex socket bolts (12).
IMPORTANT
• Install them so the cover sits flat.
8.8 N·m
Tightening torque Cover (20) 0.9 kgf·m
6.5 lbf·ft
• Tool to use : hex socket
RY9212166HYS0058US0
12. Install the cam (4) on the cover (20).
IMPORTANT
• Install it in the same position as before disassembly.
(4) Cam (20) Cover
RY9212001HYS0576US0
13. Install the camshaft (6).
IMPORTANT
• Grease the sliding part that holds the camshaft.
• Install the indentation in the cam faces up.
(4) Cam (6) Cam Shaft
RY9212001HYS0577US0
14. Apply Loctite to the threads of the hex socket bolt.
• Loctite #241
RY9212001HYS0578US0
3-S100 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
15. Install the hex socket bolt.
6.9 ± 1.0 N·m
Tightening torque Cam (4) 0.7 ± 0.1 kgf·m
5.1 ± 0.7 lbf·ft
• Tool to use : M3 hex socket
RY9212166HYS0059US0
16. Apply grease to the ends of the pushrods (16).
IMPORTANT
• Use a soft spatula to apply the grease so you don't scratch
the surfaces of the pushrods or the plugs.
(4) Cam (16) Pushrod
RY9212001HYS0580US0
17. After fitting the top of the bellows (1) onto the cam, fit the bottom
edge into the groove in the cover (20).
IMPORTANT
• Before fitting the bottom edge of the bellows into the
groove of the cover, apply an anti-rust oil to the parts inside
the bellows.
(1) Bellows (20) Cover
RY9212001HYS0581US0
3-S101 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
10. PILOT VALVE (BLADE)
[1] PILOT VALVE (BLADE) ASSEMBLY
Pilot Valve (Travel) Exploded View
(1) Valve Assembly (5) Straight Pipe Joint
(2) Filter (6) Pipe Joint
(3) O-Ring (7) Hex Socket Bolt
(4) Pipe Joint (8) Spring Washer
RY9212166HYS0126US0
Pilot Valve (Blade) Adapter Installation
(1) Valve Assembly (5) Straight Pipe Joint
(2) Filter (6) Pipe Joint
(4) Pipe Joint
RY9212166HYS0127US0
3-S102 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] PILOT VALVE (BLADE) DISASSEMBLY GUIDE
(1) Casing (12) Washer 1 (21) Hex Set Screw (30) Spring
(2) Port Plate (13) Spring Seat (22) Hex Socket Bolt (31) Lock Nut
(3) O-Ring (14) Spring Seat (23) Disc (32) Adjusting Nut
(4) Hex Socket Bolt (15) Washer 2 (24) Cam Axle (33) O-Ring
(6) Spool (16) Spring (25) Hex Set Screw (34) Hex Socket Bolt
(7) Plug (17) Spring (26) Bushing (35) Bellows
(8) Pushrod (18) Spring (27) Detent Plug
(10) Seal (19) Top Cover (28) Holder
(11) O-Ring (20) Lever (29) Steel Ball
RY9212050HYS0043US0
3-S103 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(1) Disassembly
1. Clamp the blade valve in a vise.
2. Remove the bellows (35) from the top cover (19).
3. Loosen the detents (27), (31) and (32) in order from the outside.
(19) Cover (32) Detent
(27) Detent (35) Bellows
(31) Detent
RY9212050HYS0049US0
4. Remove the hex socket bolt (22) and the lever (20).
(20) Lever (22) Hex Socket Bolt
RY9212050HYS0050US0
5. Remove the hex socket set screw (25) and the cam axle (24).
IMPORTANT
• Be careful when removing the hex socket set screw as it
was tightened with a great deal of torque and has Loctite
#241 on it.
(24) Cam Axle (25) Hex Set Screw
RY9212050HYS0051US0
6. Use the lever (20) and the hex socket bolt (22) to remove the
disc (23).
(20) Lever (23) Disc
(22) Hex Socket Bolt
RY9212050HYS0052US0
7. Remove the hex socket bolt (34) and the top cover (19).
(19) Cover (34) Hex Socket Bolt
RY9212050HYS0053US0
3-S104 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
8. If the plug (7) stays in the casing, use a slotted screwdriver to
get the plug out.
IMPORTANT
• Take care not to use too much force with the screwdriver
when removing the plug so you don't damage the plug.
• Also note that the plug may pop out due to the force of the
spring.
(7) Plug
RY9212050HYS0054US0
9. Remove the reducing valve sub-assembly and the return spring
(16).
10. Put the casing (1) to be installed into the vice upside-down.
(1) Casing (16) Spring
RY9212050HYS0055US0
Reducing valve sub-ASSY
(6) Spool
(13) Spring Seat
(15) Washer 1
(17) Spring
RY9212050HYS0056US0
11. Remove the hex socket bolt (12) and the port plate (2).
(2) Port Plate (12) Hex Socket Bolt
RY9212050HYS0057US0
12. Remove the O-ring (3) from the casing (1).
(1) Casing (3) O-Ring
RY9212050HYS0058US0
3-S105 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Assembly
1. Assemble the reducing valve sub-ASSY.
Install the secondary pressure setting spring (17) and the spring
seat (13) in that order on the spool (6), then press the spring
seat down and install the two half-circle shaped washers (15) on
the springs seat so they don't overlap.
NOTE
• Face the washers 1 (12) edge side up so they catch the
head of the spool.
• Do not press the spring seat (13) down 4 mm (0.2 in.) ≤
(6) Spool (15) Washer 1
(13) Spring Seat (17) Spring
RY9212050HYS0059US0
2. Install the O-ring (3) in the casing (1).
(1) Casing (3) O-Ring
RY9212050HYS0060US0
3. Install the port plate (2) on the casing and tighten it with the hex
socket bolts (12).
29.4 ± 2.0 N·m
Tightening torque Hex socket bolt (12) 3.0 ± 0.2 kgf·m
21.7 ± 1 lbf·ft
(2) Port Plate (12) Hex Socket Bolt
RY9212050HYS0061US0
4. Install the return spring (16) and reducing valve sub-ASSY into
the casing (1).
NOTE
• When installing the reducing valve sub-ASSY, do not hit
the bottom of the spool on the corners of the casing with
much force.
(1) Casing (16) Spring
RY9212050HYS0062US0
3-S106 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
5. Apply grease to the ends of the pushrods (8) and install them in
the casing (1).
NOTE
• If the force of the return springs is weak, the plug may be
stuck to the casing by the O-ring's resistance to sliding.
• If the force of the return springs is weak, put the top cover
on and tighten the hex socket bolts alternately so the top
cover is installed evenly.
(1) Casing (8) Pushrod
RY9212050HYS0063US0
6. Install the top cover (19) on the casing (1) and tighten the hex
socket bolts (34).
11.8 ± 1.0 N·m
Tightening torque Hex socket bolt (34) 1.2 ± 0.1 kgf·m
8.7 ± 0.7 lbf·ft
(1) Casing (34) Hex Socket Bolt
(2) Port Plate
RY9212050HYS0064US0
7. Wipe off any Loctite remaining on the screw holes on the top of
the disc (23).
8. Apply grease to the surface of the disc where the steel ball rides.
(23) Disc
RY9212050HYS0065US0
9. After inserting the disc (23) and cam axle (24), tighten the hex
socket set screw (25).
NOTE
• Wipe off any excess Loctite on the hex socket set screw.
• Apply Loctite a #241 equivalent to the surface of the hex
socket set screw.
16.7 ± 1.0 N·m
Tightening torque Hex socket set screw (25) 1.7 ± 0.1 kgf·m
12.3 ± 0.7 lbf·ft
(23) Disc (25) Hex Set Screw
(24) Cam Axle
RY9212050HYS0066US0
10. Install the lever (20) on top of the disc (23) and tighten the hex
socket bolts (22).
29.4 ± 2.0 N·m
Tightening torque Hex socket bolt (22) 3.0 ± 0.2 kgf·m
21.7 ± 1 lbf·ft
(20) Lever (23) Disc
(22) Hex Socket Bolt
RY9212050HYS0067US0
3-S107 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
11. Assemble the steel ball, the holder, washer2 and the spring
inside the detent plug (27) and test fit the lock nut and the
adjusting nut.
12. Apply plenty of grease to around the steel ball.
(27) Detent Plug
RY9212050HYS0068US0
13. Install the detent plug to the top cover (19) and tighten.
14. Turn the adjusting plug to adjust the force required to release
the detent and tighten the lock nut.
41.2 ± 2.9 N·m
Detent plug
Tightening torque 4.2 ± 0.3 kgf·m
Lock nut
30.4 ± 2.1 lbf·ft
(19) Cover
RY9212050HYS0069US0
15. Apply an anti-rust oil to the parts inside the top cover (19).
16. Install the bellows (35) to the top of the top cover.
(19) Cover (35) Bellows
RY9212050HYS0070US0
3-S108 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
11. UNLOAD VALVE
[1] UNLOAD VALVE ASSEMBLY
Unload Valve Disassembly Schematic
(1) Unload Valve
(2) Accumulator
(3) Pipe Joint (L45, G4-G4)
(4) Elbow Pipe Joint (G3-G3)
(5) Pipe Joint (L, G3/8-G1/2)
(6) Pipe Joint (L, G1/4-G1-4)
(7) Adapter
(8) Pipe Joint (T, G2, G3-G2)
(9) Pipe Joint (G1/4-G3/8)
(10) Bolt (M10 × 20)
(11) Bolt (M10 × 20)
(12) Bracket (Switch)
Bolt 39.2 to 45.1 N·m
Tightening
(M10×16) 4.0 to 4.6 kgf·m
torque
(11) 28.9 to 33.3 lbf·ft
RY9212166HYS0128US0
Unload Valve Adapter Installation
(1) Unload Valve
(2) Accumulator
(3) Pipe Joint (L45, G4-G4)
(4) Elbow Pipe Joint (G3-G3)
(5) Pipe Joint (L, G3/8-G1/2)
(6) Pipe Joint (L, G1/4-G1-4)
(7) Adapter
(8) Pipe Joint (T, G2, G3-G2)
(9) Pipe Joint (G1/4-G3/8)
(11) Bolt (M10 × 20)
(12) Bracket (Switch)
(a) 45 °
RY9212166HYS0129US0
3-S109 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] UNLOAD VALVE DISASSEMBLY / ASSEMBLY PROCEDURES
No. Name of part Q'ty Notes No. Name of part Q'ty Notes
(1) Plug 1 (12) Solenoid 2
(2) Plunger 1 (13) Screw adjustment 1
(3) Spring 1 (14) Flanged plug 2
(4) Spring 2 (15) Hex socket bolt 4
(5) Spool 2 (16) Hex socket bolt 2
(6) Plunger 1 (17) Hex nut 1
(7) Spring 1 (18) Rivet screw 2
(8) Nameplate 1 (19) O-Ring 2
(9) Cover 1 (20) O-Ring 1
(10) Plug 1 (21) O-Ring 4
(11) Body 1 (22) O-Ring 1
RY9212001HYS0584US0
3-S110 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(1) Disassembly / Assembly Procedures
Precautions during Disassembly / Assembly
The clearances of the body and spool are calculated to fit.
Be sure to check their positions during disassembly and re-install them in the same positions during assembly.
The same with the solenoid, reinstall it in the same position and orientation.
RY9212001HYS0585US0
Solenoid Valve Disassembly
1. Remove the two hex socket bolts (15) per solenoid and remove
the solenoid (12).
IMPORTANT
• Take care that the pushrods (23) do not fall out of the
solenoids (12).
3.92 N·m
Tightening torque Hex socket bolt (15) 0.4 kgf·m
2.89 lbf·ft
• Tool to use : M4 hex socket
(12) Solenoid (23) Pushrod
(15) Hex Socket Bolt
RY9212166HYS0060US0
2. Remove the O-rings.
IMPORTANT
• During assembly, install the O-rings to the solenoids and
then install them to the body.
• Apply grease to the O-rings.
(19) O-Ring
RY9212001HYS0587US0
3. Remove the flanged plug (14).
26.5 N·m
Tightening torque Flanged plug (14) 2.7 kgf·m
19.5 lbf·ft
• Tool to use : M6 hex socket
(14) Flanged Plug
RY9212166HYS0061US0
4. Remove the springs and spools.
IMPORTANT
• During assembly, apply hydraulic oil to the spool.
(4) Spring (5) Spool
RY9212001HYS0589US0
3-S111 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
5. Remove the hex nut (17) and the adjustment screw (13).
15.7 N·m
Tightening torque Hex nut (17) 1.6 kgf·m
11.6 lbf·ft
• Tool to use : M17 wrench
(13) Screw Adjustment (17) Hex Nut
RY9212166HYS0062US0
6. Remove the cover (9).
3.92 N·m
Tightening torque Hex socket bolt (16) 0.4 kgf·m
2.89 lbf·ft
• Tool to use : M4 hex socket
(9) Cover (16) Hex Socket Bolt
RY9212166HYS0063US0
7. Remove the plug.
(10) Plug
RY9212001HYS0592US0
8. Remove the O-ring.
(21) O-Ring
RY9212001HYS0593US0
9. Remove the spring.
(7) Spring
RY9212001HYS0594US0
3-S112 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
10. Remove the plunger.
IMPORTANT
• During assembly, apply hydraulic oil to the plunger.
• Tool to use : Magnet
(6) Plunger
RY9212001HYS0595US0
Check Valve Disassembly
11. Remove the plug (1).
21.0 N·m
Tightening torque Plug (1) 2.1 kgf·m
15 lbf·ft
• Tool to use : M6 hex socket
(1) Plug
RY9212166HYS0064US0
12. Remove the spring.
(3) Spring
RY9212001HYS0597US0
13. Remove the plunger.
IMPORTANT
• During assembly, apply hydraulic oil to the plunger.
(2) Plunger
RY9212001HYS0598US0
14. Remove the flanged plug (14).
26.5 N·m
Tightening torque Flanged plug (14) 2.7 kgf·m
19.5 lbf·ft
• Tool to use : M6 hex socket
(14) Flanged Plug
RY9212166HYS0065US0
Perform the procedures in reverse to assemble the parts.
RY9212001HYS0017US0
3-S113 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
12. TPSS VALVE
[1] TPSS VALVE
(1) Specifications
(1) Port 1 (PV Side) (4) Port 4 (PV Side) (6) Port B (C/V Side) (8) Port D (C/V Side)
(2) Port 2 (PV Side) (5) Port A (C/V Side) (7) Port C (C/V Side) (9) Bolt (M10 x 20)
(3) Port 3 (PV Side)
RY9212166HYS0130US0
Assembly Diagram
(1) Assy Valve, TPSS (10) Adapter
(2) Bolt (M10 x 20) (11) O-Ring
(3) Bracket (TPSS) (12) Joint, Pipe
(4) Bolt (M10 x 25) (13) O-Ring
(5) Joint, Pipe (14) Joint, Pipe
(6) Joint, Pipe (15) O-Ring
(7) O-Ring (16) Joint, Pipe
(8) Joint, Pipe (17) O-Ring
(9) O-Ring
RY9212166HYS0131US0
3-S114 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Components
No. Name of part Q'ty Notes
(1) Housing 1
(2) Shaft 1 NI Plating
(3) Washer 1
(4) Spring Pins 3 JIS B 2808 D4*16 L-A
(5) Snap ring 1 JIS B 2804 for shaft 28
(6) Oil Seal 1 VR 38A BM1220A0
(7) O-ring 1 JIS B 2401 1A P26
(8) O-ring 1 JIS B 2401 1A P32
(9) Hex socket bolt (M6x16) 2
(10) Lever 1
RY9212050HYS0073US0
3-S115 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
13. THIRD LINE VALVE ASSEMBLY
[1] THIRD LINE VALVE ASSEMBLY COMPONENTS
(1) Body (5) O-Ring (04810-00160) (9) Lever (a) A-C Port Oil Passage Lever
(2) Spool (6) O-Ring (04810-00200) (10) Washer Position
(3) Spring Pins (7) O-Ring (04811-10200) (11) Spring Pins (b) A-B Port Oil Passage Lever
(4) O-Ring (04811-10180) (8) O-Ring (04612-50180) Position
RY9212001HYS0609US0
3-S116 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] THIRD LINE HOSE ROUTE
(1) Body
(2) Spool
(3) Spring Pins
(4) O-Ring (04811-10180)
(5) O-Ring (04810-00160)
(6) O-Ring (04810-10200)
(7) O-Ring (04811-10200)
(8) O-Ring (04612-50180)
(9) Lever
(10) Washer
(11) Spring Pins
(a) AUX1 Low Pressure Port
(b) Tank Port
(c) To Boom Base Pipe (AUX1 Low Pressure
Side)
(d) To Oil Cooler
RY9212032HYS0059US0
3-S117 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
14. ROUTING OF HYDRAULIC HOSES
[1] TABLE OF HYDRAULIC HOSES
(1) Hydraulic Hoses
(A) Type C, Parallel Female Thread (a) Total Length
for Pipe (Male 30 ° Seat) (b) Metal Fitting Size
(c) 30 °
(B) Type CR4, Parallel Female Thread (a) Total Length
45 ° for Pipe (Male 30 ° Seat) (b) Metal Fitting Size
(c) 30 °
(d) 45 °
(e) Fitting Dimensions
(C) Type CR9, Parallel Female Thread (a) Total Length
90 ° for Pipe (Male 30 ° Seat) (b) Metal Fitting Size
(c) 30 °
(d) 90 °
(e) Fitting Dimensions
RY9212050HYS0074US0
3-S118 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Table of High-Pressure Hoses
Hose Metal fitting
KX057
No. Part number Total Tape Guard Used part U55-4
Size Type Size Length -4
length color
3050 mm Resin- Pump - C/V
(1) RD551-63213 1/2 White C-C G1/2 –
120.1 in. spirals (P1 Delivery)
3080 mm Resin- Pump - C/V
(2) RD551-63223 1/2 Green C-C G1/2 –
121.3 in. spirals (P2 Delivery)
2730 mm Resin- Pump - C/V
(3) RD551-63232 1/2 Pink C-C G1/2 –
107.5 in. spirals (P3 Delivery)
2665 mm Resin-
(4) RD551-63264 1/4 C-C G1/4 – Pump - C/V (PPS)
104.9 in. spirals
2930 mm Resin-
(5) RD551-63275 1/4 C-C G1/4 – Pump - C/V (PLS)
115.4 in. spirals
1110 mm R/J - Travel motor
(6) RD551-63713 5/8 White C-C G1/2 –
43.7 in. (L-FWD and R-FWD)
1150 mm R/J - Travel motor
(7) RD551-63722 5/8 C-C G1/2 –
45.3 in. (L-REV and R-REV)
R/J - Pipe
580 mm C- 37 mm
(8) RD551-63761 3/8 G3/8 (Blade allocation)
22.8 in. CR9 1.5 in.
(lifting blade)
R/J - Pipe
560 mm C- 47 mm
(9) RD551-63771 1/2 G1/2 (Blade allocation)
22.0 in. CR9 1.9 in.
(lowering blade)
Pipe (Blade
605 mm CR4 - 26 mm
(10) RD551-63781 3/8 G3/8 Spring allocation) - Blade
23.8 in. C 1.0 in.
CYL [Lifting blade]
Pipe (Blade
656 mm CR4 - 29.5 mm
(11) RD551-63791 1/2 G1/2 Spring allocation) - Blade
25.8 in. C 1.2 in.
CYL [Lowering blade]
2180 mm Resin- C/V - Boom CYL
(12) RD556-94111 1/2 Green C-C G1/2 –
85.8 in. spirals [Lifting boom]
Resin-
2450 mm C/V - Boom CYL
(13) RD556-94121 1/2 Yellow C-C G1/2 – spirals,
96.5 in. [Lowering boom]
Cover
Resin-
2270 mm C/V - Boom base pipe
(14) RD562-64131 1/2 Black C-C G1/2 – spirals,
89.4 in. [Arm dump]
Cover
Resin-
2130 mm C/V - Boom base pipe
RD562-64141 1/2 Blue C-C G1/2 – spirals,
83.9 in. [Crowd arm]
Cover
(15)
Resin-
2160 mm C/V - Boom base pipe
RD362-64141 1/2 Blue C-C G1/2 – spirals,
85.0 in. [Crowd arm]
Cover
Resin-
2250 mm C/V - Boom base pipe
RD356-94151 1/2 Red C-C G1/2 – spirals,
88.5 in. [Dump bucket]
Cover
(16)
Resin-
2200 mm C/V - Boom base pipe
RD556-94151 1/2 Red C-C G1/2 – spirals,
86.6 in. [Dump bucket]
Cover
Resin-
2200 mm C/V - Boom base pipe
(17) RD556-94161 1/2 White C-C G1/2 – spirals,
86.6 in. [Crowd bucket]
Cover
Boom end pipe -
1420 mm Resin-
RD551-64811 1/2 C-C G1/2 – Bucket CYL [Dump
55.9 in. spirals
and crowd bucket]
(18)
Boom end pipe -
1160 mm
RD551-64312 1/2 C-C G1/2 – Bucket CYL [Dump
45.7 in.
and crowd bucket]
3-S119 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Hose Metal fitting
KX057
No. Part number Total Tape Guard Used part U55-4
Size Type Size Length -4
length color
1580 mm Boom mid-pipe - Arm
(19) RD556-94341 1/2 C-C G1/2 – Cover
62.2 in. CYL [Dump arm]
800 mm Boom mid-pipe - Arm
(20) RD556-94351 1/2 C-C G1/2 – Cover
31.5 in. CYL [Crowd arm]
680 mm C- 74.5 mm C/V - R/J (D)
RD358-64411 1/2 Blue G1/2
26.8 in. CR9 2.9 in. [Travel L-FWD]
(21)
780 mm C- 46 mm C/V - R/J (D)
RD551-64412 1/2 Blue G1/2
30.7 in. CR9 1.8 in. [Travel L-FWD]
640 mm C- 46 mm C/V - R/J (F)
RD358-64421 1/2 Red G1/2
25.2 in. CR9 1.8 in. [Travel L-REV]
(22)
700 mm C- 74.5 mm C/V - R/J (F)
RD551-64422 1/2 Red G1/2
27.6 in. CR9 2.9 in. [Travel L-REV]
730 mm C- 74.5 mm C/V - R/J (E)
RD358-64431 1/2 Green G1/2
28.7 in. CR9 2.9 in. [Travel R-FWD]
(23)
810 mm C- 46 mm C/V - R/J (E)
RD551-64432 1/2 Green G1/2
31.9 in. CR9 1.8 in. [Travel R-FWD]
700 mm C- 74.5 mm C/V - R/J (G)
RD358-64441 1/2 Yellow G1/2
27.6 in. CR9 2.9 in. [Travel R-REV]
(24)
720 mm C- 74.5 mm C/V - R/J (G)
RD551-64442 1/2 Yellow G1/2
28.3 in. CR9 2.9 in. [Travel R-REV]
750 mm C- 22 mm C/V - Swivel motor
RD358-64511 1/2 Gray G1/2
29.5 in. CR4 0.9 in. [Swivel left]
(25)
760 mm C- 74.5 mm C/V - Swivel motor
RD551-64512 1/2 Gray G1/2
29.9 in. CR9 2.9 in. [Swivel left]
780 mm C- 22 mm C/V - Swivel motor
RD358-64521 1/2 Aqua G1/2
30.7 in. CR4 0.9 in. [Swivel right]
(26)
790 mm C- 46 mm C/V - Swivel motor
RD551-64522 1/2 Aqua G1/2
31.1 in. CR9 1.8 in. [Swivel right]
Green-
470 mm C- 24 mm C/V - Swing CYL
(27) RD551-64613 1/4 ish G1/4
18.5 in. CR9 0.9 in. [Swing left]
yellow
750 mm Orang C- 24 mm C/V - Swing CYL
(28) RD551-64622 1/4 G1/4
29.5 in. e CR9 0.9 in. [Swing right]
590 mm C- 70 mm C/V - R/J (C)
RD358-64711 3/8 Pink G3/8
23.2 in. CR9 2.8 in. [Lift blade]
(29)
670 mm C- 70 mm C/V - R/J (C)
RD551-64711 3/8 Pink G3/8
26.4 in. CR9 2.8 in. [Lift blade]
490 mm C- 22 mm C/V - R/J (C)
RD358-64721 1/2 Green G1/2
19.3 in. CR4 0.9 in. [Lower blade]
(30)
580 mm C- 22 mm C/V - R/J (C)
RD551-64722 1/2 Green G1/2
22.8 in. CR4 0.9 in. [Lower blade]
Resin-
2220 mm C/V - Boom base pipe
RD358-92311 1/2 Pink C-C G1/2 – spirals,
87.4 in. [AUX1 Hi]
Cover
(31)
Resin-
2145 mm C/V - Boom base pipe
RD551-92312 1/2 Pink C-C G1/2 – spirals,
84.5 in. [AUX1 Hi]
Cover
Resin-
2220 mm C/V - Boom base pipe
RD358-92321 1/2 Green C-C G1/2 – spirals,
87.4 in. [AUX1 Low]
Cover
(32)
Resin-
2155 mm C/V - Boom base pipe
RD551-92322 1/2 Green C-C G1/2 – spirals,
84.8 in. [AUX1 Low]
Cover
Boom mid-pipe - Pipe
740 mm
(33) RD551-92413 5/8 C-C G1/2 – Cover [AUX1 Hi and Low]
29.1 in.
<AUX1 Spec>
3-S120 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Hose Metal fitting
KX057
No. Part number Total Tape Guard Used part U55-4
Size Type Size Length -4
length color
Boom end pipe -
905 mm
(34) RD568-92511 5/8 C-C G1/2 – Spring Arm side block [AUX1
35.6 in.
Hi and Low]
2680 mm C/V - Boom mid-pipe
(35) RD551-92611 3/8 Gray C-C G3/8 – Cover
105.5 in. [AUX2 Hi]
Resin-
2760 mm C/V - Boom mid-pipe
(36) RD551-92621 3/8 Aqua C-C G3/8 – spirals,
108.7 in. [AUX2 Low]
Cover
790 mm Boom mid-pipe - Pipe
(37) RD551-92652 3/8 C-C G3/8 – Cover
31.1 in. [AUX2 Hi and Low]
Boom end pipe -
760 mm
(38) RD568-92681 3/8 C-C G3/8 – Spring Arm side block [AUX2
29.9 in.
Hi and Low]
520 mm R/J - Pipe (ANG
(39) RD558-74271 3/8 C-C G3/8 –
20.5 in. allocation) (ANG left)
R/J - Pipe
380 mm
(40) RD558-74281 3/8 C-C G3/8 – (ANG allocation)
15.0 in.
(ANG right)
695 mm CR4 - 26 mm Pipe (ANG allocation)
(41) RD558-74871 3/8 G3/8 Spring
27.4 in. C 1.0 in. - ANG CYL [ANG left]
Pipe (ANG allocation)
1135 mm CR4 - 26 mm
(42) RD558-74881 3/8 G3/8 Spring - ANG CYL
44.7 in. C 1.0 in.
[ANG right]
Green-
630 mm C- 38 mm C/V - R/J (I) [ANG
(43) RD558-74181 3/8 ish G3/8
24.8 in. CR9 1.5 in. left]
yellow
560 mm Orang C- 26 mm C/V - R/J (J)
(44) RD558-74192 3/8 G3/8
22.0 in. e CR4 1.0 in. [ANG right]
RY9212166HYS0066US0
3-S121 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Deliver Hose Routing
(a) Control Valve Assembly (b) Pump Assembly (Piston)
RY9212166HYS0067US0
3-S122 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(4) Delivery Hose Clamp Positions
(1) Red (A) Pass the Hose Under the Rod.
(2) Blue (B) Hang the Plastic Tube-Wrapped
(3) White Hose On the Round Rod of the
(4) Pink Guide (Hose PP).
(5) Green (C) Must Not Touch the Weight.
(6) Yellow (D) Clamps (2 Places)
(E) Clamps (2 Places)
(F) No Hoses Touching.
RY9212166HYS0138US0
3-S123 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(5) Suction Pipe and Hose Routing
(1) Hose (Suction 1) (A) Hose Clamp (50-65)
(2) Pipe (Suction Pipe) (B) Hose Clamp (50-65)
(3) Hose (Suction 2) (C) Hose Clamp (58-75)
(D) Hose Clamp (58-75)
RY9212166HYS0139US0
3-S124 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(6) Installation of Pipes (Suction)
Apply thread compound (Loctite 271) on the pipe (suction) (3)
and attach to the frame with the torque indicated below.
48.1 to 55.9 N·m
Tightening torque Pipe (suction) (3) 4.9 to 5.7 kgf·m
35.5 to 41.2 lbf·ft
(1) Hose (Suction 1) (5) Bolt (M6)
(2) Hose Clamp (50-65) (6) Hose (Suction 2)
(3) Pipe (Suction) (7) Hose Clip (58-75)
(4) Insulation (Suction Pipe)
RY9212166HYS0068US0
(7) Front Hose Routing (U55-4)
(1) Black (4) Red (7) Gray (9) Pink
(2) Yellow (5) White (8) Blue (10) Green
(3) Green (6) Aqua
AUX 1 Spec
• Route the six hoses according to color of tape and clamp them with a plastic tie, then put two AUX1 hoses
(according to tape color) on top and clamp all eight hoses with a plastic tie.
(a)
AUX 2 Spec
• Route the eight hoses according to color of tape and clamp them with a plastic tie, then put two AUX1 hoses
(according to tape color) on top and clamp all 10 hoses with a plastic tie.
(b) • Gather the hoses with green tape (lift boom) and yellow tape (lower boom) and clamp with plastic tie.
AUX 1 Spec
• Route the six hoses according to color of tape and clamp them with a plastic tie.
(c)
AUX 2 Spec
• Route the eight hoses according to color of tape and clamp them with a plastic tie.
RY9212166HYS0081US0
3-S125 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(8) Front Hose Routing (KX057-4)
(1) Black (4) Red (7) Gray (9) Pink
(2) Yellow (5) White (8) Blue (10) Green
(3) Green (6) Aqua
AUX 1 Spec
• Route the six hoses according to color of tape and clamp them with a plastic tie, then put two AUX1 hoses
(according to tape color) on top and clamp all eight hoses with a plastic tie.
(a)
AUX 2 Spec
• Route the eight hoses according to color of tape and clamp them with a plastic tie, then put two AUX1 hoses
(according to tape color) on top and clamp all 10 hoses with a plastic tie.
(b) • Gather the hoses with green tape (lift boom) and yellow tape (lower boom) and clamp with plastic tie.
AUX 1 Spec
• Route the six hoses according to color of tape and clamp them with a plastic tie.
(c)
AUX 2 Spec
• Route the eight hoses according to color of tape and clamp them with a plastic tie.
RY9212166HYS0082US0
3-S126 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(9) High-Pressure Hydraulic Hose Routing (Front)
(a) Control Valve (d) Arm (Rod) (g) Bucket (Rod) (i) AUX2 / Thumb (Bottom)
(b) Cylinder, ASSY (Boom) (e) Arm (Bottom) (h) AUX1 (Low) (j) AUX2 / Thumb (Rod)
(c) AUX1 (High) (f) Bucket (Bottom)
RY9212166HYS0140US0
(10) High-Pressure Hydraulic Hose Routing (Travel, Swivel, Blade, Swing)
(a) Control Valve Assembly (b) Motor, ASSY (Swivel) (d) Cylinder, ASSY (Swing) (e) Clamp at the Point with
(c) Rotary Joint, ASSY Greenish-Yellow Tape
RY9212166HYS0070US0
3-S127 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(11) High-Pressure Hydraulic Hose Routing (Travel, Swivel, Blade, Angle,
Swing)
(a) Control Valve Assembly (b) Motor, ASSY (Swivel) (d) Cylinder, ASSY (Swing) (e) Clamp at the Point with
(c) Rotary Joint, ASSY Greenish-Yellow Tape
RY9212166HYS0141US0
(12) High-Pressure Hydraulic Hose Routing (Travel, Blade Swivel)
Travel motor / cylinder
S/J side
side
A 2-speed pilot L/R travel 2-speed
B Lower blade Cylinder-bottom side
C Lift blade Cylinder-rod side
D Left forward Left P1
E Right forward right P2
F Left backward left P2
G Right backward right P1
H Drain L/R drain port (upper)
(a) Blade Cylinder
(b) Swivel Joint
(c) Wheel Motor Left Side
(d) Wheel Motor Right Side
(e) Bracket
(A) Clamp the 2-Speed Pressure Increase Signal
Hose and the P1 Hose (Right Track). (Do Not
Come in Contact with the Track Frame.)
RY9212050HYS0082US0
3-S128 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(13) High-Pressure Hydraulic Hose Routing (Travel, Blade, Angle, Swivel)
Travel motor / cylinder
S/J side
side
A 2-speed pilot L/R travel 2-speed
B Lower blade Cylinder-bottom side
C Lift blade Cylinder-rod side
D Left forward Left P1
E Right forward right P2
F Left backward left P2
G Right backward right P1
H Drain L/R drain port (upper)
I Angle Cylinder-bottom side
J Angle Cylinder-rod side
(a) Blade Cylinder
(b) Swivel Joint
(c) Wheel Motor Left Side
(d) Wheel Motor Right Side
(e) Bracket
(f) Angle Blade Cylinder
(A) Clamp the 2-Speed Pressure Increase Signal
Hose and the P1 Hose (Right Track). (Do Not
Come in Contact with the Track Frame.)
RY9212050HYS0083US0
3-S129 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(14) Hose Routing Inside the Track Frame (Standard Spec)
(A) Blade Hose Bracket and (E) Not to Come in Strong (a) Clamp (e) The Corner of the Right Side
Connections with Contact with Track Frame or (b) Protective Tubing Fastening Bracket has a Bevel to
Cylinder-Side Hoses each Other (Same Left / Tape Identify It.
(B) Blade Hose Bracket and Right). (c) Install the Left / Right (f) 10 °
Connections with (F) Install Tape on the Swivel Brackets so the Welded Nut
Swivel-Side Hoses Joint Side. Comes Forward.
(C) So Hoses Do Not Kink when (G) Clamp the 2-Speed Signal (d) Hoses to Take a Horizontal
Blade Moves Up / Down Hose with the Path (Align with the
(Left/Right Same) High-Pressure Hose at this Horizontal Position of the
(D) Hoses Not to Touch Track Point (Right Side). Welded Nut, Same Right /
Frame (Left / Right Same) Left)
RY9212050HYS0084US0
3-S130 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(15) Hose Routing Inside the Track Frame (Angle Spec)
(A) Connections from the Hose (F) Install Tape on the Swivel (a) Clamp (f) Connect the Top Hose to the
Connecting Bracket to the Joint Side. (b) Protective Tubing Fastening Angle Cylinder Bottom Side
Cylinder (G) Clamp the 2-Speed Signal Tape Port.
(B) Blade Hose Bracket and Hose with the (c) Install the Left/Right (g) Connect Lower Hoses to the
Connections with High-Pressure Hose at this Brackets so the Welded Nut Angle Cylinder Rod Side
Swivel-Side Hoses Point (Right Side Only). Comes Forward. Ports.
(C) Route so Hoses Do Not Kink (H) The Aim of Routing the (d) Blade Hoses to Take a (h) Connect the Top Side to the
from Up/Down or Angled Angle Cylinder Bottom Side Horizontal Path (Align with I Port of the Swivel Joint.
Right/Left Movement. Hose is so it Passes by the the Horizontal Position of (i) Connect the Lower Side to
(D) Hoses Not to Touch Track Outside of the Pin Boss the Welded Nut, Same the Port of the Swivel Joint.
Frame (Left/Right Same) when the Blade is at Its Right/Left) (j) 10 °
(E) Not to Come in Strong Neutral Position. (20 °) (e) The Corner of the Right Side (k) 90 °
Contact with Track Frame or Bracket has a Bevel to
each Other (Same Identify It.
Left/Right).
RY9212050HYS0085US0
3-S131 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(16) Swivel Hose Routing (KX057-4)
(A) STD Version (a) Install Directly Toward the (b) Install the Hose in the Gap (c) 10 °
(B) Angle Blade Version C/V (Travel Left Fwd) so it Just Misses Other (d) 20 °
Pipes and Hoses. (Lift (e) 30 °
Dozer) (f) 33 °
RY9212050HYS0086US0
3-S132 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(17) Swivel Hose Routing (U55-4)
(A) STD Version (a) Install the Hose Leaving (c) Install the Travel Hose (d) 10 °
(B) Angle Blade Version Room for at Least One Hose (Right Rev) so Its Hose (e) 25 °
(Travel Left Fwd). Band can be Tightened from (f) 30 °
(b) Install Parallel to the Travel Above. (g) 40 °
Left Fwd Hose (Travel Right
Fwd).
RY9212050HYS0087US0
3-S133 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[2] TABLE OF HYDRAULIC HOSES (LOW-PRESSURE HOSES)
(1) Table of Hydraulic Hoses
Hose Metal fitting
KX057
No. Part number Total Tape Guard Used part U55-4
Size Type Size Length -4
length color
410 mm CR9 - 46 mm
(1) RD451-63512 1/2 G1/2 Unload valve - O/T [T]
16.1 in. C 1.8 in.
1230 mm
(2) RD551-63612 5/8 White C-C – Tubes C/V (T2) - O/C
48.4 in.
600 mm C-
(3) RD451-63623 5/8 White – Tubes O/C - Return pipe
23.6 in. CR4
1110 mm R/J - Travel motor
(4) RD451-63741 – – –
43.7 in. [Drain (left and right)]
380 mm R/J - O/T
(5) RD451-64472 – – –
15.0 in. [Travel motor drain]
510 mm R/J - O/T
(5) RD551-64551 – – –
20.1 in. [Travel motor drain]
630 mm C/V - Swivel motor
(6) RD358-64531 5/8 White C-C G1/2 – Tubes
24.8 in. [Makeup]
570 mm C- 22 mm C/V - Swivel motor
(6) RD551-64533 5/8 White G1/2 Tubes
22.4 in. CR4 0.9 in. [Makeup]
780 mm Travel motor - O/T
(7) RD358-64551 – – –
30.7 in. [Drain]
510 mm Travel motor - O/T
(7) RD551-64551 – – –
20.1 in. [Drain]
340 mm C- 46 mm Third line valve - C/V
(8) RD551-92522 5/8 G1/2
13.4 in. CR9 1.8 in. (T2)
RY9212166HYS0072US0
(2) Table of Protective Tubing
Hose Metal fitting
KX057
No. Part number Total Tape Guard Used part U55-4
Size Type Size Length -4
length color
1000 mm
(9) RC411-43051 – Low-pressure hose (4)
39.4 in.
400 mm
(10) 68191-63451 – Low-pressure hose (5)
15.7 in.
140 mm
(10) RD45-64481 – Low-pressure hose (5)
5.5 in.
400 mm
(11) 68191-63451 – Low-pressure hose (7)
15.7 in.
650 mm
(11) RD358-64561 – Low-pressure hose (7)
25.6 in.
RY9212166HYS0073US0
3-S134 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) Drain Hose Routing
(a) Control Valve (e) Swivel Joint (h) Bracket (L, Oil Cooler) (i) Install this Hose so It
(b) Hose (Return, Cooler) (f) Bracket (R, Oil Cooler) Doesn't Get Kinked.
(c) Pipe (Return, Cooler) (g) Pipe (Oil Cooler)
(d) Motor, ASSY (Swivel)
Note) The number in parentheses that appears after the hose number is the protective tube number.
RY9212050HYS0090US0
3-S135 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[3] TABLE OF HYDRAULIC HOSES (PILOT HOSES)
(1) Table of Pilot Hoses
Hose Fixture
KX057
No. Part number Total Tape Dimen- Guard Point used U55-4
Size Type Size -4
length color sions
2040 mm Quick - 24 mm TPSS (A) - C/V [Lift
(1) RD368-62511 1/4 Green G1/4
80.3 in. CR9 0.9 in. boom]
2790 mm Quick - 24 mm TPSS (A) - C/V [Lift
(1) RD558-62512 1/4 Green G1/4
109.8 in. CR9 0.9 in. boom]
2110 mm Quick - 24 mm TPSS (C) - C/V [Lower
(2) RD358-62522 1/4 Yellow G1/4
83.1 in. CR9 0.9 in. boom]
2820 mm Quick - 24 mm TPSS (C) - C/V [Lower
(2) RD558-62523 1/4 Yellow G1/4
111.0 in. CR9 0.9 in. boom]
1230 mm Quick - 44.5 mm TPSS (D) - C/V [Dump
(3) RD358-62531 1/4 Black G1/4
48.4 in. CR9 1.8 in. arm]
2820 mm Quick - 44.5 mm TPSS (D) - C/V [Dump
(3) RD568-62531 1/4 Black G1/4
111.0 in. CR9 1.8 in. arm]
2020 mm Quick - 44.5 mm TPSS (B) - C/V
(4) RD358-62541 1/4 Blue G1/4
79.5 in. CR9 1.8 in. [Crowd arm]
2820 mm Quick - 44.5 mm TPSS (B) - C/V
(4) RD558-62541 1/4 Blue G1/4
111.0 in. CR9 1.8 in. [Crowd arm]
1490 mm Quick - 44.5 mm Steering P/V - C/V
(5) RD368-62552 1/4 Red G1/4
58.66 in. CR9 1.8 in. [Dump bucket]
3550 mm Quick - 24 mm Steering P/V - C/V
(5) RD568-62552 1/4 Red G1/4
139.8 in. CR9 0.9 in. [Dump bucket]
2180 mm Quick - 24 mm Steering P/V - C/V
(6) RD368-62561 1/4 White G1/4
85.8 in. CR9 0.9 in. [Crowd bucket]
3060 mm Quick - 24 mm Steering P/V - C/V
(6) RD568-62563 1/4 White G1/4
120.5 in. CR9 0.9 in. [Crowd bucket]
2160 mm Quick - 24 mm Steering P/V - C/V
(7) RD368-62571 1/4 Gray G1/4
85.0 in. CR9 0.9 in. [Swivel left]
4170 mm Quick - 24 mm Steering P/V - C/V
(7) RD568-62571 1/4 Gray G1/4
164.2 in. CR9 0.9 in. [Swivel left]
2820 mm Quick - 24 mm Steering P/V - C/V
(8) RD368-62581 1/4 Aqua G1/4
111.0 in. CR9 0.9 in. [Swivel right]
3710 mm Quick - 24 mm Steering P/V - C/V
(8) RD568-62581 1/4 Aqua G1/4
146.1 in. CR9 0.9 in. [Swivel right]
2280 mm Quick - 44.5 mm Blade P/V - C/V [Lift
(9) RD358-62611 1/4 Pink G1/4
89.8 in. CR9 1.8 in. blade]
2500 mm Quick - 24 mm Blade P/V - C/V [Lift
(9) RD551-62613 1/4 Pink G1/4
98.4 in. CR9 0.9 in. blade]
1710 mm Quick - 44.5 mm Blade P/V - C/V
(10) RD358-62621 1/4 Green G1/4
67.3 in. CR9 1.8 in. [Lower blade]
3870 mm Quick - 24 mm Blade P/V - C/V
(10) RD558-62624 1/4 Green G1/4
152.4 in. CR9 0.9 in. [Lower blade]
Green
2610 mm Quick - 44.5 mm Swing P/V - C/V
(11) RD358-62632 1/4 ish G1/4
102.8 in. CR9 1.8 in. [Swing left]
yellow
Green
1370 mm Quick - 44.5 mm Swing P/V - C/V
(11) RD551-62631 1/4 ish G1/4
53.9 in. CR9 1.8 in. [Swing left]
yellow
1940 mm Orang Quick - 44.5 mm Swing P/V - C/V
(12) RD358-62642 1/4 G1/4
76.4 in. e CR9 1.8 in. [Swing right]
2550 mm Or- Quick - 24 mm Swing P/V - C/V
(12) RD551-62641 1/4 G1/4
100.4 in. ange CR9 0.9 in. [Swing right]
2570 mm Quick - 24 mm Travel P/V - C/V [left
(13) RD358-62652 1/4 Blue G1/4
101.2 in. CR9 0.9 in. fwd]
3-S136 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Hose Fixture
KX057
No. Part number Total Tape Dimen- Guard Point used U55-4
Size Type Size -4
length color sions
1880 mm Quick - 44.5 mm Travel P/V - C/V [left
(13) RD551-62651 1/4 Blue G1/4
74.0 in. CR9 1.8 in. fwd]
1890 mm Quick - 32 mm Travel P/V - C/V [left
(14) RD358-62662 1/4 Red G1/4
74.4 in. CR9 1.3 in. bwd]
2850 mm Quick - 24 mm Travel P/V - C/V [left
(14) RD551-62661 1/4 Red G1/4
112.2 in. CR9 0.9 in. bwd]
2570 mm Quick - 24 mm Travel P/V - C/V [right
(15) RD358-62672 1/4 Green G1/4
101.2 in. CR9 0.9 in. fwd]
1890 mm Quick - 44.5 mm Travel P/V - C/V [right
(15) RD551-62671 1/4 Green G1/4
74.4 in. CR9 1.8 in. fwd]
1890 mm Quick - 44.5 mm Travel P/V - C/V [right
(16) RD358-62682 1/4 Yellow G1/4
74.4 in. CR9 1.8 in. bwd]
2820 mm Quick - 24 mm Travel P/V - C/V [right
(16) RD551-62681 1/4 Yellow G1/4
111.0 in. CR9 0.9 in. bwd]
215 mm Swing - Steering P/V - TPSS
(17) RD568-62751 1/4 Green –
8.5 in. Quick [Lift boom]
260 mm Swing - Steering P/V - TPSS
(18) RD568-62761 1/4 Yellow –
10.2 in. Quick [Lower boom]
1230 mm Quick - 24 mm Steering P/V - TPSS
(19) RD358-62831 1/4 Black G1/4
48.43 in. CR9 0.9 in. [Dump arm]
1190 mm Quick - 24 mm Steering P/V - TPSS
(19) RD568-62831 1/4 Black G1/4
46.9 in. CR9 0.9 in. [Dump arm]
1300 mm Quick - 24 mm Steering P/V - TPSS
(20) RD358-62841 1/4 Blue G1/4
51.18 in. CR9 0.9 in. [Crowd arm]
1250 mm Quick - 24 mm Steering P/V - TPSS
(20) RD568-62841 1/4 Blue G1/4
49.2 in. CR9 0.9 in. [Crowd arm]
Four-way
760 mm Quick - 24 mm proportioning valve or
(21) RD458-62711 1/4 Pink G1/4
29.9 in. CR9 0.9 in. AUX1 proportioning
valve - C/V [AUX1 Hi]
Four-way
290 mm proportioning valve or
(22) RD458-62721 1/4 Green C-C G1/4 –
11.4 in. AUX1 proportioning
valve - C/V [AUX1 low]
1050 mm C- Colgate Pump (drain) - nothing
(23) RD458-63151 3/16 G1/4 –
41.3 in. Quick tube [Air bleed]
2040 mm Plumber,
(24) RD568-63245 3/8 C-C G3/8 – Pump (P4) - Line filter
80.3 in. tube
400 mm 26 mm Line filter - Unload
(25) RD568-63251 3/8 CR4 - C G3/8
15.7 in. 1.0 in. valve [P]
Swivel motor - P
1520 mm 38 mm
(26) RD358-63283 3/8 C - CR9 G3/8 collector block 5
59.8 in. 1.5 in.
[Swivel brake release]
Swivel motor - P
1170 mm 38 mm
(26) RD451-63285 3/8 C - CR9 G3/8 collector block 5
46.1 in. 1.5 in.
[Swivel brake release]
670 mm 44.5 mm
(27) RD551-63293 1/4 CR9 - C G1/4 Unload valve - C/V [AI]
26.4 in. 1.8 in.
1930 mm Quick - 24 mm Steering P/V (left) - P
(28) RD568-63313 1/4 G1/4
75.98 in. CR9 0.9 in. collector block 3 [P]
1070 mm Quick - 24 mm Steering P/V (right) -
(29) RD568-63322 1/4 G1/4
42.13 in. CR9 0.9 in. Steering P/V (left)
1270 mm Quick - 24 mm Steering P/V (right) -
(29) RD368-63321 1/4 G1/4
50 in. CR9 0.9 in. Steering P/V (left)
1200 mm Quick - 24 mm Blade P/V (left) - P
(30) RD451-63334 1/4 G1/4
47.2 in. CR9 0.9 in. collector block 4 [P]
3-S137 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Hose Fixture
KX057
No. Part number Total Tape Dimen- Guard Point used U55-4
Size Type Size -4
length color sions
620 mm 24 mm Swing P/V - Travel PV
(31) RD358-63341 1/4 CR9 - C G1/4 Plumber
24.4 in. 0.9 in. [P]
620 mm 24 mm Swing P/V - Travel PV
(31) RD451-63341 1/4 CR9 - C G1/4
24.4 in. 0.9 in. [P]
300 mm 38 mm Travel PV - Swivel
(32) RD358-63352 3/8 CR9 - C G3/8
11.8 in. 1.5 in. motor [P]
330 mm 38 mm Travel PV - Swivel
(32) RD451-63353 3/8 CR9 - C G3/8
13.0 in. 1.5 in. motor [P]
Four-way
proportioning valve or
670 mm 24 mm
(33) RD458-63361 1/4 C - CR9 G1/4 AUX1 proportioning
26.4 in. 0.9 in.
valve - Unload valve
[P]
Unload valve - P
1480 mm
(34) RD451-63385 3/8 C-C G3/8 – collector block 1 [P
58.3 in.
base pressure]
1760 mm Quick - Steering P/V (left) -
(35) RD451-63413 1/4 G1/4 –
69.3 in. C O/T left down [T]
1180 mm Quick - Steering P/V (right) -
(36) RD451-63423 1/4 G1/4 –
46.5 in. C O/T right down [T]
980 mm Quick - 24 mm
(37) RD568-63433 1/4 G1/4 Blade P/V - O/T [T]
38.6 in. CR4 0.9 in.
1470 mm Quick - 24 mm
(38) RD358-63442 1/4 G1/4 Swing P/V - O/T [T]
57.9 in. CR4 0.9 in.
1550 mm Quick - 24 mm
(38) RD451-63442 1/4 G1/4 Swing P/V - O/T [T]
61.0 in. CR4 0.9 in.
620 mm CR9 - 24 mm Swing P/V - Travel PV
(39) RD568-63451 1/4 G1/4
24.4 in. Quick 0.9 in. [T]
Four-way
proportionating valve
530 mm 24 mm or AUX1
(40) RD458-63461 1/4 C - CR9 G1/4
20.9 in. 0.9 in. proportionating valve
O/T (proportionating
valve T) (P)
C/V (P1) to C/V (Pa5)
860 mm 24 mm
(41) RD451-63551 1/4 Yellow C - CR9 G1/4 (boom lock valve
33.9 in. 0.9 in.
release)
C/V (DR) to O/T
720 mm
(42) RD451-63581 1/4 C-C G1/4 – (boom lock valve
28.3 in.
drain)
1250 mm 29 mm R/J to travel motor
(43) RD451-63731 1/4 C - CR9 G1/4
49.21 in. 1.1 in. (2-speed left and right)
470 mm 24 mm
(43) RD551-63911 1/4 CR9 - C G1/4 C/V (PP1) - C/V (PP2)
18.5 in. 0.9 in.
600 mm 24 mm
(44) RD551-63921 1/4 CR9 - C G1/4 C/V (PP1) - C/V (PP3)
23.6 in. 0.9 in.
300 mm Quick -
(45) RD551-63931 1/4 G1/4 – C/V (PF1) - C/V (PF2)
11.8 in. C
2580 mm CR9 - 24 mm Unload valve - R/J
(46) RD358-64461 1/4 G1/4 Plumber
101.6 in. Quick 0.9 in. [2-speed]
2350 mm CR9 - 24 mm Unload valve - R/J
(46) RD551-64462 1/4 G1/4 Plumber
92.5 in. Quick 0.9 in. [2-speed]
Horsepower control
440 mm Quick - proportionating valve
(47) RD568-61071 1/4 G1/4 –
17.3 in. C (A) - Hydraulic pump
(CH1)
3-S138 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Hose Fixture
KX057
No. Part number Total Tape Dimen- Guard Point used U55-4
Size Type Size -4
length color sions
Horsepower control
280 mm Quick - 24 mm proportionating valve
(48) RD568-61081 1/4 G1/4
11.0 in. CR9 0.9 in. (P) - Hydraulic pump
(PP) [Control]
Hydraulic pump (CH2)
310 mm Quick - - Horsepower control
(49) RD568-61091 1/4 G1/4 –
12.2 in. C proportionating valve
(T)
3110 mm Quick - Operation P/V (right
(50) RD568-63561 1/4 G1/4 –
122.4 in. C P) - Pilot filter
2580 mm Quick - 24 mm Unload valve - R/J
(51) RD358-64461 1/4 G1/4
101.6 in. CR9 0.9 in. (2-speed)
2350 mm CR9 - 24 mm Unload valve - R/J
(51) RD551-64461 1/4 G1/4
92.52 in. Quick 0.9 in. (2-speed)
Four-way
1210 mm 24 mm
(52) RD358-62731 1/4 Gray C - CR9 G1/4 proportioning valve -
47.6 in. 0.9 in.
C/V [AUX2 Hi]
Four-way
1150 mm 24 mm
(52) RD558-62732 1/4 Gray C - CR9 G1/4 proportioning valve -
45.3 in. 0.9 in.
C/V [AUX2 Hi]
Four-way
520 mm
(53) RD558-62741 1/4 Aqua C-C G1/4 – proportioning valve -
20.5 in.
C/V [AUX2 Low]
ANG solenoid valve -
500 mm 24 mm four-way proportioning
(54) RD458-75811 1/4 C - CR9 G1/4
19.7 in. 0.9 in. valve or AUX1
proportioning valve [P]
280 mm Quick - 24 mm ANG solenoid valve -
(55) RD458-75822 1/4 G1/4
11.0 in. CR9 0.9 in. O/T [T]
1360 mm Or- 24 mm ANG solenoid valve -
(56) RD458-75831 1/4 C - CR9 G1/4
53.5 in. ange 0.9 in. C/V [ANG rod]
Green
460 mm ANG solenoid valve -
(57) RD558-75842 1/4 ish C-C G1/4 –
18.1 in. C/V [ANG bottom]
yellow
RY9212166HYS0083US0
3-S139 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Pilot Hose Routing (P)
(a) Control Valve (d) Filter, Assy (Pressure) (f) Valve ASSY (h) Valve ASSY (ANG, Switch)
(b) Pump Assembly (Piston) (e) Valve ASSY (Unload) (Proportional, 4)
(c) Coupler (Block PP) (g) Swivel Joint, ASSY
RY9212166HYS0075US0
(3) Pilot Hose Routing (P)
(a) Valve Assembly (PV Travel) (b) Valve, ASSY (PV Swing) (c) Pilot Valve (Left) (f) Valve ASSY (PV, Blade)
(d) Pilot Valve (Right) (g) Motor, ASSY (Swivel)
(e) Coupler (Block PP)
RY9212166HYS0076US0
3-S140 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(4) Pilot Hose Routing (T)
(a) Valve Assembly (PV Travel) (b) Valve, ASSY (PV Swing) (c) Pilot Valve (Left) (e) Valve ASSY (PV, Blade)
(d) Pilot Valve (Right) (f) Valve ASSY (Proportional)
RY9212166HYS0077US0
3-S141 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(5) Pilot Hose Routing (Front)
(a) Control Valve (b) Pilot Valve (Left) (c) Pilot Valve (Right) (d) Valve, ASSY (TPSS)
RY9212166HYS0078US0
3-S142 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(6) Pilot Hose Routing (Travel, Blade, Swing, AUX1, AUX2)
(a) Control Valve (c) Valve, ASSY (d) Valve Assembly (PV, Swing) (e) Valve, ASSY (PV, Travel)
(b) Valve, ASSY (PV, Blade4) (Four-Way, Solenoid)
RY9212166HYS0079US0
3-S143 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(7) Pilot Hose Routing (Travel, Blade, Swing, AUX1, AUX2, Angle)
(a) Control Valve (c) Valve, ASSY (d) Valve Assembly (PV, Swing) (f) Valve, ASSY
(b) Valve, ASSY (PV, Blade4) (Four-Way, Solenoid) (e) Valve, ASSY (PV, Travel) (2-Way, Solenoid)
(g) Valve, ASSY (ANG)
RY9212166HYS0080US0
3-S144 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(8) Pilot Hose Routing (Control Valve) (KX057-4)
(a) 20 ° (c) 10 ° (e) Clamp All Hose with Speed (f) Install so the Hose Do Not
(b) 15 ° (d) 5 ° Clamps. Kink.
RY9212050HYS0098US0
3-S145 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(9) Pilot Hose Routing (Control Valve) (U55-4)
(a) 30 ° (d) Install these 4 Hoses at such (e) Install the Bundle of Pilot (f) Install so the Hoses Do Not
(b) 20 ° an Angle that they Do Not Hoses so they Pass Kink.
(c) 10 ° Interfere Greatly with each between the PP1 to PP2 and
other or with Part B of the PP1 to PP3 Hoses.
Base (Valve).
RY9212050HYS0099US0
3-S146 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(10) Overall Routing of Pilot Hoses (Front of Machine) (KX057-4)
(a) Pass the 2-Speed Travel (b) Clamp with a Speed Clamp. (c) After Gathering the Unload (d) To Steering P/V
Hose between the Round V and CV Pilot Hoses
Pipe and the Vertical Rib of Together, Clamp them
the Swivel Frame and then Together with a Speed
behind the Makeup Hose of Clamp.
the Swivel Motor.
RY9212050HYS0100US0
3-S147 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(11) Overall Routing of Pilot Hoses (Front of Machine) (U55-4)
(a) Route the 2-Speed Travel (d) Clamp All Hoses with Speed (e) Route the Pilot hoses so (h) Clamp with a Speed Clamp.
Hoses Inside the Round Clamps. Use Green Tape they Hang on the Guide (i) After Gathering the Unload
Pipe. and the Battery Box Guide (Round Rod) Welded to the V and CV Pilot Hoses
(b) Clamp All the Hoses with (Round Rod) to Keep the Travel Frame. Together, Clamp them
Speed Clamps. Delivery Hoses from (f) Route the Bundle of Pilot Together with a Speed
(c) Clamp the Bundle of Hoses Touching. Hoses by the Guide (Round Clamp.
to the Guide Bar of the Rod).
Battery Box with a Speed (g) To Steering, Dozer P/V
Clamp.
RY9212050HYS0101US0
3-S148 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(12) Overall Routing of Pilot Hoses (Right Side of Machine) (KX057-4)
(a) Aim for Directly above PB3 (g) Hang from the Round Rod (l) Gather the Boom Lock Dr (m) Hang the Hose (CV - Unload
(b) Hoses Not to Touch each (h) Install with a Gap of at Least and 2-Speed Travel Pilot Valve) on the Round Rod
other 20 mm (0.79 in.) from Base Pressure Hoses Welded to the Return Pipe.
(c) Aim for CV Block Mounting Solenoid Parts. Together at the White Tape (n) (Angle Spec Only) Hose Not
Bolts (i) Install so Hoses Do Not and Clamp with Speed to Touch Solenoid.
(d) To Travel, Swing P/V Touch the Boom Lock (Dr) Clamps. (AUX2 Spec):
(e) To Swivel Joint 2-Speed Adapter or Hoses. Clamp the AUX2 Low Hose
Travel Port (j) Clamp with them as well at the
(f) Clamp with Speed Clamp(s). (k) Clamp the 2-Speed Travel White Tape. (Angle Spec):
Aim for Midway between and Pilot Base-Pressure Clamp the Angle (Right)
white Tape and Hose Base. Hoses to the Round Rod Hose with them as well at
Welded to the Return Pipe. the White Tape.
RY9212050HYS0102US0
3-S149 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(13) Overall Routing of Pilot Hoses (Right of Machine) (U55-4)
(a) Clamp the 2-Speed Travel (g) Hang on the Round Rod (l) Gather the Boom Lock Dr (m) Hang on the Round Rod
Hose and Travel Left Fwd (h) Install with a Gap of at Least and 2-Speed Travel Pilot Welded to the Return Pipe.
(Yellow2) Hoses with Speed 20 mm (0.79 in.) from Base Pressure Hoses (n) To Pilot Valve for each
Clamps. Solenoid Parts. Together at the White Tape Operation
(b) Aim for Directly above PB3 (i) Install so Hoses Do Not and Clamp with Speed
(c) Hoses Not to Touch each Touch the Boom Lock (Dr) Clamps. (AUX2 Spec):
other Adapter or Hoses. Clamp the AUX2 Low Hose
(d) To Swivel Joint 2-Speed (j) Clamp with them as well at the
Travel Port (k) Clamp the 2-Speed Travel White Tape. (Angle Spec):
(e) Clamp with Speed Clamp(s). and Pilot Base Pressure Clamp the Angle (Right)
Aim for Midway between Hoses to the Round Rod Hose with them as well at
White Tape and Hose Base. Welded to the Return Pipe. the White Tape.
(f) Aim for CV Block Mounting
Bolts
RY9212050HYS0103US0
3-S150 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(14) Pilot Hose Routing (Around the Driver's Seat)
(a) Clamp with a Speed Clamp. (c) Hook the Bundle of Pilot (d) To Oil Tank and Control (e) Arm Crowd
(b) Mounting Angle for TPSS Hoses on the Guide (Round Valve (f) Arm Dump
Valve Hose (Arm Side Hose) Rod) and Pass It Through.
RY9212174HYS0222US0
3-S151 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
15. HYDRAULIC DEVICE PERFORMANCE
MEASUREMENT
Piston Pump Air Bleeding Procedure
When disassembling hydraulic equipment and replacing hoses,
etc., or after changing the hydraulic fluid and using the vacuum
pump, before operating the machine, be sure to carry out air
bleeding to prevent pump scorching and cavitation.
1. After operating, with the engine stopped, remove the hose at the
top of the pump from its clamp.
2. Press in the hexagonal plug and the black plastic lock section
as well. Then hold the black plastic lock section and pull out the
hexagonal plug.
3. Drape the hose on the front of the weight, and leave for
30 seconds.
4. Fit a hexagonal plug to the hose, start and idle the engine, and
check whether there is any cavitation noise from the pump.
5. Repeat operations in 2. 3. 4 until pump cavitation noise
disappears.
6. When cavitation noise disappears, raise the engine speed to
1500 rpm, slowly operated the arm and check whether
cavitation noise is emitted. (Make sure there is no relief when
operating the arm.)
7. If there is no cavitation noise, raise the engine speed to
2000 rpm, slowly operate the arm, and check again for
cavitation noise. If cavitation noise is emitted, stop the engine
and carry out 2. 3.
8. If there is no cavitation noise in step 7, raise the engine speed
to maximum rpm, slowly operate the aim, and check again for
cavitation noise. If cavitation noise is emitted, stop the engine
and carry out 2. 3. (Make sure there is no relief when operating
the arm.)
9. If there was no cavitation noise when performing step 8, air
bleeding is finished. Clamp the air bleed hose in its original
position.
(1) Air Bleed Hose (3) Lock Section
(2) Hexagonal Plug
RY9212166HYS0086US0
(1) Air Bleed Hose (2) Hexagonal Plug (3) Clamp
RY9212166HYS0087US0
3-S152 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Hydraulic System Pressure Release Procedure
1. Place the mini excavator on flat hard ground, lower the bucket
and the blade, and stop the engine.
RY9212001HYS0647US0
2. Without starting the engine, place the engine starter switch in
the "RUN" (B) position.
(1) Starter Switch (A) STOP
(B) RUN
(C) START
RY9212001HYS0648US0
3. Place the machine lock lever in the release position.
(1) Machine Lock Lever (A) Release
(B) Lock
RY9212001HYS0649US0
4. Operate each control lever for the boom, arm, bucket and swivel
to full stroke.
5. Operate the travel lever, blade lever, swing pedal each to full
stroke.
6. Switch on the AUX port using the AUX port enable switch
(switch3), and operate AUX port knob switches each to full
stroke.
7. Place the machine's lock lever in the "Lock" position, and the
engine starter switch to the "STOP" position.
(1) Left Machine Control Lever (5) Blade Control Lever
(2) Right Machine Control Lever (6) AUX Port Knob Switch
(3) Travel Lever Left (7) Swing Pedal
(4) Travel Lever Right (8) AUX Port Enable Switch (Switch3)
RY9212032HYS0103US0
3-S153 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Main Pump Flow
(1) Pump (4) Flow Meter (6) Test Hose (8) Pressure Gauge
(2) Control Valve (5) Joint (7) Oil Catcher (9) EP Mode Solenoid Valve
(3) Oil Cooler
Measurement preparation
1. Place the mini excavator on flat, hard ground, lower the bucket and the blade, and stop the engine.
2. Follow the chapter "Releasing Hydraulic System Pressure" and release pressure in the hydraulic lines.
3. Use a vacuum pump and attach a pressure gauge to the pressure measurement port and Pi port.
If measuring P1 and P2 flow (combined flow)
1. Disconnect the control valve side of the P1 and P2 hoses and plug the control valve's P1 and P2 ports.
2. Connect the P1 and P2 hoses and the test hoses and connect them to the IN side of the flow meter.
(Combine the flows with an adapter.)
3. Disconnect the hose connecting the 2-way valve and the control valve (T2) on the control valve (T2) side and plug
the disconnected hose.
4. Connect the control valve (T2) and the OUT side of the flow meter with a test hose.
5. Disconnect the control valve side of the PPS hose and plug the control valve's PPS port.
6. Place the PPS hose in an oil catcher.
7. Remove the vacuum pump.
8. Bleed the pump of air and make sure there are no oil leaks in any of the pipes.
If measuring P3 flow
1. Disconnect the control valve side of the P3 delivery hose and plug port P3 of the control valve.
2. Connect the P3 delivery hose and the test hose and connect it to the IN side of the flow meter.
3. Disconnect the hose connecting the 2-way valve and the control valve (T2) on the control valve (T2) side and plug
the disconnected hose.
4. Connect the control valve (T2) and the OUT side of the flow meter with a test hose.
5. Disconnect the control valve side of the PPS hose and plug the control valve's PPS port.
6. Place the PPS hose in an oil catcher.
7. Remove the vacuum pump.
8. Bleed the pump of air and make sure there are no oil leaks in any of the pipes.
RY9212166HYS0088US0
3-S154 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Measurement
Open the loading valve of the flow meter and start the engine.
Set the engine speed to maximum, gradually close the loading valve
of the flow meter, and measure the flow and engine speed at each
pressure level.
Perform the measurement 3 times, take the average and use
this as the measurement value.
[ Measurement Conditions ]
• Engine RPM: Max. RPM
• Eco mode switch: P mode
• Hydraulic oil temperature: 50 ± 5 °C (122 ± 9 °F)
[ Pump performance inspection procedure ]
The pump performance inspection is placing a specified
pressure load on the pump discharge and performing measurement
at a specified engine speed to check the volumetric efficiency.
1. The pump volumetric efficiency is proportional to pump
rotational speed and inverse proportional to load pressure so
set the engine speed at maximum speed for the test.
2. Volumetric efficiency is the ratio of the discharge amount per
revolution (cc/rev) at a specified load and the theoretical
discharge amount (calculated value). The specified load is the
main relief set pressure.
3. The measurement value of the discharge flow at the specified
load must be corrected to one pump revolution because the
rotational speed of the pump is reduced from its normal speed.
(1) Pump (6) Test Hose
(2) Control Valve (7) Plug
(3) Oil Cooler (8) Tank
(4) Flow Meter (9) Adapter
(5) Joint
RY9212166HYS0089US0
3-S155 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
AUX Proportional Limit Flow Volume
[Measurement Procedure]
1. Place the machine on flat hard ground, lower the bucket and the
blade, and stop the engine.
2. Follow the chapter Releasing Pressure in the Hydraulic System
to release pressure in the hydraulic lines.
3. Connect a vacuum pump.
4. Connect the AUX discharge (high-pressure side) and the IN
side of the flow meter with a test hose.
5. Connect the OUT side of the flow meter and the AUX discharge
(low-pressure side) with a test hose.
6. Remove the vacuum pump.
7. Open the loading valve of the flow meter all the way and start
the engine.
8. Operate the meter panel and measure the flow when at each
limit.
9. Perform the measurement 3 times; take the average and use
this as the measurement value.
[Measurement Conditions]
• Engine speed : Max. rpm
• Eco mode switch : P mode
• Oil temperature : 50 ±5°C (122 ±9°F)
IMPORTANT
• Ensure that the oil flow direction and the input direction
into the flow meter are correct.
• Refer to the Operator's Manual for how to set the limit
values.
(1) Test Hose (A) AUX High-Pressure Side
(2) Flow Meter (B) AUX Low-Pressure Side
RY9212166HYS0100US0
3-S156 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
AUX flow
[Measurement Procedure]
1. Place the machine on flat hard ground, lower the bucket and the
blade, and stop the engine.
2. Follow the chapter Releasing Pressure in the Hydraulic System
to release pressure in the hydraulic line.
3. Connect a vacuum pump.
4. Connect the AUX discharge (high-pressure side) and the IN
side of the flow meter with a test hose.
5. Connect the OUT side of the flow meter and the AUX discharge
(low-pressure side) with a test hose.
6. Remove the vacuum pump.
7. Open the loading valve of the flow meter all the way and start
the engine.
8. Set engine speed to max. rpm and then carry out AUX
operation.
9. Gradually close the flow meter loading valve and measure the
oil flow at each pressure.
10. Perform the measurement 3 times; take the average and use
this as the measurement value.
[Measurement Conditions]
• Engine speed : Max. rpm
• Eco mode switch : P mode and E mode
• Oil temperature : 50 ±5°C (122 ±9°F)
IMPORTANT
• Ensure that the oil flow direction and the input direction
into the flow meter are correct.
(1) Test Hose (A) AUX High-Pressure Side
(2) Flow Meter (B) AUX Low-Pressure Side
RY9212166HYS0101US0
3-S157 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Pilot pressure
Pilot 1 Primary Pressure Measuring Procedure
1. Place the machine on flat hard ground, lower the bucket and the
blade, and stop the engine.
2. Follow the chapter Releasing Residual Pressure in the
Hydraulic System to release pressure from the hydraulic line.
3. Set up the pressure gauge on the inlet side of the pilot filter.
4. Start and idle the engine, and check that there is no oil leakage
when the machine's lock lever is released.
5. Raise the engine speed to maximum rpm, and measure the pilot
pressure under zero load.
Perform the measurement 3 times; take the average and use
this as the measurement value.
[Measurement Conditions]
• Engine speed : Max. rpm
• Eco mode switch : P mode
• Oil temperature : 50 ±5°C (122 ±9°F)
Pilot 1 Primary Pressure Adjustment Method
1. Loosen the relief valve lock nut (1) on the unload valve (3). Use
a hexagonal wrench to turn the adjuster screw (2), and tighten
the lock nut.
2. After adjusting, check the set pressure.
15.7 N·m
Tightening torque Lock nut (1) 1.6 kgf·m
11.6 lbf·ft
(1) Lock Nut (a) Pressure Increase
(2) Adjuster Screw (b) Pressure Decrease
(3) Unload Valve
RY9212166HYS0090US0
3-S158 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Pilot 2 Primary Pressure Measuring Procedure
1. Place the machine on flat hard ground, lower the bucket and the
blade, and stop the engine.
2. Follow the chapter Releasing Residual Pressure in the
Hydraulic System to release pressure from the hydraulic line.
3. Fit a T-joint to the pilot port on the control valve side to be
measured, and attach a pressure gage.
4. Start and idle the engine, and check that there is no oil leakage.
5. Set the engine to maximum rpm, operate the lever to be tested
and measure the secondary pilot pressure at full stroke.
6. Perform the measurement 3 times; take the average and use
this as the measurement value.
[Measurement Conditions]
• Engine speed : Max. rpm
• Eco mode switch : P mode
• Oil temperature : 50 ±5°C (122 ±9°F)
(1) Pressure Gauge (2) Adapter
RY9212166HYS0091US0
(1) T1 Port (12) Travel Right Forward (Pb6) (23) T2 Port (33) AUX2 (Pb10)
(2) AUX1 (Pb1) (13) Travel Right Reverse (Pa6) (24) T3 Port (34) AUX2 (Pa10)
(3) AUX1 (Pa1) (14) Travel Left Forward (Pb7) (25) PP1 Port (35) Angle Blade Bottom (Pb11)
(4) Swivel Right (Pb2) (15) Travel Left Reverse (Pa7) (26) PP2 Port (36) Angle Blade Rod (Pa11)
(5) Swivel Left (Pa2) (16) Swing Bottom (Pb8) (27) PP3 Port
(6) Bucket Bottom (Pb3) (17) Swing Rod (Pa8) (28) PPS1 Port (a) Main Travel Right Relief
(7) Bucket Rod (Pa3) (18) Blade Rod (Pb9) (29) PF1 Port Valve (aTR)
(8) Arm Bottom (Pb4) (19) Blade Bottom(Pa9) (30) PF2 Port (b) Main Travel Left Relief Valve
(9) Arm Rod (Pa4) (20) P1 Port (31) PAi Port (aTL)
(10) Boom Bottom (Pb5) (21) P2 Port (32) PLS Port (c) Main P3 Relief Valve (aP3)
(11) Boom Rod (Pa5) (22) P3 Port (d) Main LS Relief Valve (aLS)
RY9212166HYS0143US0
3-S159 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Main relief valve pressure
[Measurement Procedure]
1. Place the machine on flat hard ground, lower the bucket and the
blade, and stop the engine.
2. Follow the chapter on "Release of pressure in the hydraulic
system" to release pressure in the hydraulic line.
3. Set up the pressure gauge at the detection port of the adapter
on the pump discharge side to be measured.
4. Start and idle the engine, and check that there is no oil leakage.
5. Slowly operate the control lever of the front operation to be
measured, operate until the cylinder reaches the end of its
stroke, then relieve.
6. In the case of travel, lock the travel section, gradually operate
the travel lever, then relieve.
7. Perform the measurement 3 times; take the average and use
this as the measurement value.
[Measurement Conditions]
• Engine speed : Max. rpm
• Eco mode switch : P mode
• Oil temperature : 50 ±5°C (122 ±9°F)
Main Relief Valve Adjustment Procedure
1. Loosen the relief valve lock nut (4). Use a hexagonal wrench to
turn the adjuster screw (5), and tighten the lock nut.
2. Operate the lever at maximum engine speed, and check the
pressure setting.
27 to 31 N·m
Tightening torque Lock nut (4) 2.8 to 3.2 kgf·m
20 to 23 lbf·ft
(1) Pump 1 Pressure Detection Port (a) Pressure Increase
(2) Pump 2 Pressure Detection Port (b) Pressure Decrease
(3) Pump 3 Pressure Detection Port
(4) Lock Nut
(5) Adjuster Screw
RY9212166HYS0093US0
3-S160 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Main Relief Valve Layout Diagram
(1) T1 Port (12) Travel Right Forward (Pb6) (23) T2 Port (33) AUX2 (Pb10)
(2) AUX1 (Pb1) (13) Travel Right Reverse (Pa6) (24) T3 Port (34) AUX2 (Pa10)
(3) AUX1 (Pa1) (14) Travel Left Forward (Pb7) (25) PP1 Port (35) Angle Blade Bottom (Pb11)
(4) Swivel Right (Pb2) (15) Travel Left Reverse (Pa7) (26) PP2 Port (36) Angle Blade Rod (Pa11)
(5) Swivel Left (Pa2) (16) Swing Bottom (Pb8) (27) PP3 Port
(6) Bucket Bottom (Pb3) (17) Swing Rod (Pa8) (28) PPS1 Port (a) Main Travel Right Relief
(7) Bucket Rod (Pa3) (18) Blade Rod (Pb9) (29) PF1 Port Valve (aTR)
(8) Arm Bottom (Pb4) (19) Blade Bottom(Pa9) (30) PF2 Port (b) Main Travel Left Relief Valve
(9) Arm Rod (Pa4) (20) P1 Port (31) PAi Port (aTL)
(10) Boom Bottom (Pb5) (21) P2 Port (32) PLS Port (c) Main P3 Relief Valve (aP3)
(11) Boom Rod (Pa5) (22) P3 Port (d) Main LS Relief Valve (aLS)
RY9212166HYS0144US0
Measuring the Overload Relief Valve Pressure
IMPORTANT
• If it is necessary to check the overload relief pressure on this machine, measure the main relief pressure
of each circuit (boom, arm, bucket, blade, AUX and angle) and if the main relief pressures are within
factory specifications, the overload relief valve is judged to be normal.
• If there is a problem, we recommend replacing the overload relief valve as an assembly.
• If a measurement has to be made for some reason, the procedures is as follows.
(1) Pressure Measuring Kit
(2) Straight Pipe Joint
(G3/8-G1/4)
(3) Straight Pipe Joint
(G1/2-G3/8)
RY9212166HYS0153US0
3-S161 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
[Measurement preparations]
1. Place the excavator on flat hard ground, lower the bucket and the blade, and stop the engine.
2. Follow the chapter Release of Residual Pressure in the Hydraulic System and release the residual pressure in
the hydraulic lines.
3. Use the vacuum pump and disconnect the high pressure hose from the port where the overload relief valve to be
measured is mounted and plug the hose.
4. Attach the pressure measuring kit to the disconnected port.
5. Remove the vacuum pump.
6. Hydraulic oil temperature of 50 ± 5 °C (122 ± 9 °F).
[Measurement]
1. Increase the pressure with the pressure measuring kit until the overload relief valve opens.
2. Measure the pressure three times, determine the average and take that as the measured value.
CAUTION
• When disconnecting the pressure measuring kit, take appropriate care in removing it as the line is
pressurized.
RY9212148HYS0329US0
Overload Relief Valve Layout Diagram
(1) T1 Port (12) Travel Right Forward (Pb6) (23) T2 Port (33) AUX2 (Pb10)
(2) AUX1 (Pb1) (13) Travel Right Reverse (Pa6) (24) T3 Port (34) AUX2 (Pa10)
(3) AUX1 (Pa1) (14) Travel Left Forward (Pb7) (25) PP1 Port (35) Angle Blade Bottom (Pb11)
(4) Swivel Right (Pb2) (15) Travel Left Reverse (Pa7) (26) PP2 Port (36) Angle Blade Rod (Pa11)
(5) Swivel Left (Pa2) (16) Swing Bottom (Pb8) (27) PP3 Port
(6) Bucket Bottom (Pb3) (17) Swing Rod (Pa8) (28) PPS1 Port (a) Main Travel Right Relief
(7) Bucket Rod (Pa3) (18) Blade Rod (Pb9) (29) PF1 Port Valve (aTR)
(8) Arm Bottom (Pb4) (19) Blade Bottom(Pa9) (30) PF2 Port (b) Main Travel Left Relief Valve
(9) Arm Rod (Pa4) (20) P1 Port (31) PAi Port (aTL)
(10) Boom Bottom (Pb5) (21) P2 Port (32) PLS Port (c) Main P3 Relief Valve (aP3)
(11) Boom Rod (Pa5) (22) P3 Port (d) Main LS Relief Valve (aLS)
RY9212166HYS0094US0
3-S162 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Pressure measurement kit for overload relief valve
No. Name of part Number
(1) Support 1
(2) Pipe joint (M12-G2) 1
(3) Bolt (M10 x 35) 2
(4) Nut (M12) 2
(5) Test hose 1
CAUTION
• Use a test hose that can withstand pressure up to the
measurement pressure.
A : Nozzle Tester
RY9212166HYS0103US0
(1) Support
A 100 mm (3.94 in.)
B 50 mm (2.0 in.)
C t = 2.3 mm (0.09 in.)
D 70 mm (2.8 in.)
E 15 mm (0.59 in.)
F 600 mm (23.6 in.)
G 2–11 mm (2–0.43 in.)
Material std.: STKR400
RY9212148HYS0337US0
(2) Pipe joint (M12-G1/4)
A 47 mm (1.8 in.)
B 12 mm (0.47 in.)
C 15 mm (0.59 in.)
D 20 mm (0.79 in.)
E 10 mm (0.39 in.) ≤
F 12 mm (0.47 in.) ≤
G 8 mm (0.3 in.)
H 3 mm (0.1 in.)
I 18 mm (0.71 in.)
J 9.5 ± 0.2 mm (0.37 ± 0.01 in.)
K 19 +0, –0.35 mm (0.75 +0, –0.01 in.)
L 21.9 mm (0.86 in.)
M M12 × 1.5
N G1/4
O 0.52 rad (30 °)
RY9212148HYS0309US0
3-S163 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
EP proportional solenoid pressure
[Measurement Procedure]
1. Place the machine on flat hard ground, lower the bucket and the
blade, and stop the engine.
2. Follow the chapter Releasing Pressure in the Hydraulic System
to release pressure in the hydraulic lines.
3. Connect a vacuum pump.
4. Disconnect the hose from the EP proportional solenoid valve to
the pump, on the valve side, attach an adapter and a pressure
gauge, and set up the pressure gauge.
5. Start and idle the engine, and check that there is no oil leakage.
6. Measurement is to be carried out at idling speed and zero load
(control level at neutral).
7. Switch Eco mode switch between P mode and E mode and
measure pressure in each mode.
[Measurement Conditions]
• Engine speed : Idling
• Eco mode switch : P mode and E mode
• Oil temperature : 50 ±5°C (122 ±9°F)
(1) Adapter (3) Test Hose
(2) Pressure Gauge
RY9212166HYS0104US0
Unload LS valve pressure
[Measurement Procedure]
1. Place the machine on flat hard ground, lower the bucket and the
blade, and stop the engine.
2. Follow the chapter on "Release of pressure in the hydraulic
system" to release pressure in the hydraulic line.
3. Set up the pressure gauge at the detection port of the adapter
on the pump discharge side.
4. Start and idle the engine, and check that there is no oil leakage.
5. Raise engine speed to maximum rpm, and measure the
pressure at zero load (control lever in neutral).
6. Perform the measurement 3 times; take the average and use
this as the measurement value.
[Measurement Conditions]
• Engine speed : Max. rpm
• Eco mode switch : P mode
• Oil temperature : 50 ±5°C (122 ±9°F)
(1) Pump 1 Pressure Detection Port (4) LS Unload Valve
(2) Pump 2 Pressure Detection Port (5) LS Main Relief Valve
(3) Pump 3 Pressure Detection Port
RY9212166HYS0095US0
3-S164 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Swivel relief valve pressure
1. Place the machine on flat hard ground, lower the bucket and the
blade, and stop the engine.
2. Follow the chapter Releasing Residual Pressure in the
Hydraulic System to release pressure from the hydraulic line.
3. Set up the pressure gauge at the detection port (1) or (2) of the
adapter on the pump discharge side.
4. Start and idle the engine, and check that there is no oil leakage.
5. Place the bucket against something robust, lock the machine so
that it does not move, slowly operate the swivel lever from left to
right and from right to left, and take the relief pressure reading
at maximum engine speed.
Perform the measurement 3 times; take the average and use
this as the measurement value.
[Measurement Conditions]
• Engine speed : Max. rpm
• Eco mode switch : P mode
• Oil temperature : 50 ±5°C (122 ±9°F)
NOTE
• When measuring the relief valve pressure of the swivel
motor at the pressure detection port side of the pump, the
pressure is about 10% higher than the relief valve pressure
setting. For more accurate measurement, attach the
pressure gauge to the swivel motor.
(1) Pump 1 Pressure Detection Port (4) Swivel Right Relief Valve
(2) Pump 2 Pressure Detection Port (5) Swivel Left Relief Valve
(3) Pump 3 Pressure Detection Port
RY9212166HYS0096US0
Swivel motor drain volume
1. Before measuring, repeat swivel left and right operations to
sufficiently warm up the swivel motor. Hydraulic oil temperature
of 50 ±5 °C (122 ±9°F).
2. Place the machine on flat hard ground, lower the bucket and the
blade, and stop the engine.
3. Follow the chapter Releasing Residual Pressure in the
Hydraulic System to release pressure from the hydraulic line.
4. Connect a vacuum pump.
5. Disconnect the swivel motor drain hose from the swivel motor,
and insert a plug in the disconnected hose.
6. Connect the test hose (e.g., low-pressure polyvinyl hose) to the
drain port on the swivel motor.
7. Remove the vacuum pump.
8. Operate the swivel lever at full stroke for one minute with the
engine at maximum rpm, and while maintaining a uniform swivel
rate, collect the hydraulic fluid from the drain hose in a
receptacle and measure.
9. Take the measurement from right to left and left to right, three
times each, and determine the average value.
[Measurement Conditions]
• Engine speed : Max. rpm
• Eco mode switch : P mode
• Oil temperature : 50 ±5°C (122 ±9°F)
CAUTION
• Before commencing measurement, make sure there are no
persons or obstacles within the swivel range.
(a) 1 m (40 in.)
RY9212166HYS0097US0
3-S165 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Travel mode drain volume
1. Before measurement, turn on the travel motor and warm up
sufficiently.
2. Place the machine on flat hard ground, lower the bucket and the
blade, and stop the engine.
3. Follow the chapter Releasing Residual Pressure in the
Hydraulic System to release pressure from the hydraulic line.
4. Connect a vacuum pump.
5. Disconnect the travel motor drain hose from the travel motor,
and insert a plug in the disconnected hose.
6. Connect the test hose (eg., low-pressure use polyvinyl hose) to
the drain port on the travel motor side.
7. After disconnecting the vacuum pump, start the engine, jack up
the machine and raise the crawler above ground level.
CAUTION
• Place safety blocks and supports under the jacked up
machine to prevent it from dropping.
8. Rotate the crawler on the measurement side for one minute with
the engine at maximum rpm, collect hydraulic fluid from the test
hose in a receptacle and measure. Take the measurement from
right to left and left to right, three times each, and determine the
average value.
[Measurement Conditions]
• Engine speed : Max. rpm
• Eco mode switch : P mode
• Oil temperature : 50 ±5°C (122 ±9°F)
CAUTION
• For safety's sake, keep hands and feet out from under the
crawler.
RY9212166HYS0098US0
Swivel Block Performance
1. Before measuring, repeat swivel left and right operations to
sufficiently warm up the swivel motor. Set the hydraulic fluid
temperature to 50 ± 5 °C (122 ± 9 °F).
2. Place dirt or a weight of the specified weight (JIS heap x specific
gravity 1.8) in the bucket.
3. For this measurement, set the machine on a slope angle of 20 °
with the front perpendicular to the sloping surface.
4. The front attitude should be with the arm cylinder fully
compressed and bucket cylinder fully extended, holding the
boom on a straight line between the boom base pin and bucket
pin.
5. Place markers on the circumference of the swivel bearing and
track frame.
6. Start the engine, release the safety lock lever at idling rpm (lever
down), and measure the slippage over one minute.
7. Take the measurement from right to left and left to right three
times, and determine the average value.
CAUTION
• Before commencing measurement, make sure there are no
persons or obstacles within the swivel range.
RY9212166HYS0099US0
3-S166 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Travel Block Performance
1. Before measuring turn on the travel motor and give it a thorough
warm up. Set the hydraulic fluid temperature to 50 ± 5 °C
(122 ± 9 °F).
2. For this measurement, set the machine on a slope angle of 20 °.
3. Stop the machine on the slope, and set the front to travel
attitude.
4. Place the travel lever in neutral and stop the engine.
5. Make marks in the track frame and crawler, and measure the
slippage of ten minutes.
RY9212166HYS0108US0
Gravity fall amount of hydraulic cylinder
1. Before measuring, repeat front operations and fully warm up
each cylinder. Set the hydraulic fluid temperature to 50 ± 5 °C
(122 ± 9 °F).
2. Place dirt or a weight of the specified weight (JIS heap x specific
gravity 1.8) in the bucket.
3. The front attitude should be with arm cylinder fully compressed,
bucket cylinder fully extended, and bucket bottom
approximately 1 m (40 in.) above ground level. Note that the
arm cylinder should return about 50 mm (2.0 in.) from the stroke
end, and be outside the cushion range.
4. Stop the engine, and place marks on the boom, arm and bucket
cylinder rods.
5. After ten minutes has elapsed, measure the boom cylinder
compression, arm cylinder extension and bucket cylinder
compression.
RY9212032HYS0071US0
Hydraulic Cylinder Operating Time
Boom cylinder measurement
1. Before measuring, repeat front operations and fully warm up
each cylinder. Set the hydraulic fluid temperature to 50 ± 5 °C
(122 ± 9 °F).
2. The attitude for measurement should be with maximum
compressed length of the arm cylinder and bucket cylinder.
3. Raise the engine speed to maximum rpm, operate the boom
control lever to full stroke, and measure the time required from
the bucket ground contact position (maximum down position) to
maximum up position (position above ground). (Do not include
cushion operating time.)
RY9212001HYS0668US0
3-S167 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Arm cylinder measurement
1. Before measuring, repeat front operations and fully warm up
each cylinder. Set the hydraulic fluid temperature to 50 ± 5 °C
(122 ± 9 °F).
2. With the engine at maximum rpm, operate the arm control lever
to full stroke, and measure the time required for arm in and out.
RY9212001HYS0669US0
Bucket cylinder measurement
1. Before measuring, repeat front operations and fully warm up
each cylinder. Set the hydraulic fluid temperature to 50 ± 5 °C
(122 ± 9 °F).
2. With the engine at maximum rpm, operate the bucket control
lever to full stroke, and measure the time required for bucket
crowd and dump.
RY9212001HYS0670US0
Swing cylinder measurement
1. Before measuring, repeat front operations and fully warm up
each cylinder. Set the hydraulic fluid temperature to 50 ± 5 °C
(122 ± 9 °F).
2. The front attitude should be with arm cylinder fully compressed,
bucket cylinder fully extended, and bucket bottom
approximately 1 m (40 in.) above ground level.
3. At maximum engine rpm, perform a full throttle stroke swing
from left to right and right to left, and measure the time required
to achieve this.
RY9212001HYS0671US0
Blade cylinder measurement
1. Before measuring, repeat front operations and fully warm up
each cylinder. Set the hydraulic fluid temperature to 50 ± 5 °C
(122 ± 9 °F).
2. The vehicle attitude for measurement should be jacked up by
the front, assuring full stroke of cylinder, top to bottom.
3. With the engine at maximum rpm, operate the blade control
lever to full stroke, and measure the time required for blade up
and down operation.
RY9212001HYS0672US0
Measurement of required swivel time
1. Before measuring, repeat left-right swivel operation to
thoroughly warm up the swivel motor. Set the hydraulic fluid
temperature to 50 ± 5 °C (122 ± 9 °F).
2. The attitude for measurement should be with maximum
extension of the boom cylinder, arm cylinder and bucket
cylinder.
3. At maximum engine rpm, operate the swivel control lever at full
stroke, and measure the time taken for three turns of the swivel
unit.
CAUTION
• Before commencing measurement, make sure there are no
persons or obstacles within the swivel range.
RY9212001HYS0673US0
3-S168 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Travel Speed
1. Before measuring, adjust the left and right crawlers to even
tension, and operate the travel motor to thoroughly warm it up.
Set the hydraulic fluid temperature to 50 ± 5 °C (122 ± 9 °F).
2. The measuring attitude should be travel attitude.
3. At maximum engine rpm, perform a 5 m (200 in.) run-up and
10 m (390 in.) forward run, and measure the time required.
(a) Run-up [5 m (200 in.)] (b) Measuring area [10 m (390 in.)]
RY9212001HYS0674US0
Amount of travel drift
1. Before measuring, adjust the left and right crawlers to even
tension, and operate the travel motor to thoroughly warm it up.
Set the hydraulic fluid temperature to 50 ± 5 °C (122 ± 9 °F).
2. Determine a 10 m travel course on firm, flat ground, and set the
measuring attitude to travel attitude.
3. At maximum engine rpm, travel for 10 m (390 in.), and measure
the amount of drift (a).
4. Perform the measurement three times, backwards and
forwards; determine the average value, and take this as the
measured value.
(a) Travel Drift (b) 10 m (390 in.)
RY9212001HYS0675US0
3-S169 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
16. CHART OF MEASURED VALUES FOR HYDRAULIC
DEVICE PERFORMANCE
(1) Piston pump power constant characteristics 1 (measured values) [KX057-4, U55-4]
(1) Pi = 3.6 MPa (PA, QA) (2) Pi = 0 MPa (PB, QB) (a) Discharge Flow Rate : Q (b) Discharge Pressure : P
(L/min) (MPa)
Pump input RPM : 2200 rpm
Gear pump pressure : P3 = 2 MPa (20 kgf/cm2, 300 psi) Gear pump pressure : P3 = 2 MPa (20 kgf/cm2, 300 psi)
Pi pressure : Pi = 3.6 MPa (37 kgf/cm2, 520 psi) Pi pressure : Pi = 0 MPa (0 kgf/cm2, 0 psi)
Measurement pressure MPa Discharge flow rate (L/min) Measurement pressure MPa Discharge flow rate (L/min)
(kgf/cm2) [psi] (U.S. gals.) (kgf/cm2) [psi] (U.S. gals.)
PA1 = 2.5 (25) [360] QA1 = 109 (28.8) PB1 = 2.5 (25) [360] QB1 = 108 (28.5)
PA2 = 5.0 (51) [730] QA2 = 108 (28.5) PB2 = 5.0 (51) [730] QB2 = 108 (28.5)
PA3 = 7.5 (76) [1100] QA3 = 106 (28.0) PB3 = 7.5 (76) [1100] QB3 = 84.1 (22.2)
PA4 = 10.0 (100) [1400] QA4 = 106.5 (28.13) PB4 = 10.0 (100) [1400] QB4 = 66.9 (17.7)
PA5 = 12.5 (127) [1810] QA5 = 105.7 (27.92) PB5 = 12.5 (127) [1810] QB5 = 54.5 (14.4)
PA6 = 15.0 (150) [2200] QA6 = 87.1 (23.0) PB6 = 15.0 (150) [2200] QB6 = 46.8 (12.4)
PA7 = 17.5 (178) [2540] QA7 = 64.3 (17.0) PB7 = 17.5 (178) [2540] QB7 = 38.2 (10.1)
PA8 = 20.0 (200) [2900] QA8 = 52.3 (13.8) PB8 = 20.0 (200) [2900] QB8 = 30.6 (8.08)
PA9 = 22.5 (229) [3260] QA9 = 44.6 (11.8) PB9 = 22.5 (229) [3260] QB9 = 21.9 (5.79)
PA10 = 25.0 (255) [3630] QA10 = 33.7 (8.9) PB10 = 25.0 (255) [3630] QB10 = 16.2 (4.28)
PA11 = 27.4 (279) [3970] QA11 = 26.9 (7.11) PB11 = 27.4 (279) [3970] QB11 = 15.3 (4.04)
CAUTION
• Measured values may vary depending on the machine.
• This data is of values converted to the rated RPM.
• The usage limit is 80% of the discharge volume.
RY9212166HYS0145US0
3-S170 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(2) Piston pump power constant characteristics 2 (measured values) [KX057-4, U55-4]
(1) Pi = 3.6 MPa (PA, QA) (2) Pi = 0 MPa (PB, QB) (a) Discharge Flow Rate : Q (b) Discharge Pressure : P
(L/min) (MPa)
Pump input RPM : 2200 rpm
Gear pump pressure : P3 = 19.1 MPa (195 kgf/cm2, 2770 psi) Gear pump pressure : P3 = 19.1 MPa (195 kgf/cm2, 2770 psi)
Pi pressure : Pi = 3.6 MPa (37 kgf/cm2, 520 psi) Pi pressure : Pi = 0 MPa (0 kgf/cm2, 0 psi)
Measurement pressure MPa Discharge flow rate (L/min) Measurement pressure MPa Discharge flow rate (L/min)
(kgf/cm2) [psi] (U.S. gals.) (kgf/cm2) [psi] (U.S. gals.)
PA1 = 2.5 (25) [360] QA1 = 108.4 (28.64) PB1 = 2.5 (25) [360] QB1 = 85.2 (22.5)
PA2 = 5.0 (51) [730] QA2 = 107.6 (28.42) PB2 = 5.0 (51) [730] QB2 = 64.0 (17)
PA3 = 7.5 (76) [1100] QA3 = 100.7 (26.6) PB3 = 7.5 (76) [1100] QB3 = 55.7 (14.7)
PA4 = 10.0 (100) [1400] QA4 = 80.0 (21.0) PB4 = 10.0 (100) [1400] QB4 = 48.2 (12.7)
PA5 = 12.5 (127) [1810] QA5 = 60.9 (16.1) PB5 = 12.5 (127) [1810] QB5 = 40.5 (10.7)
PA6 = 15.0 (150) [2200] QA6 = 53.3 (14.1) PB6 = 15.0 (150) [2200] QB6 = 32.0 (8.5)
PA7 = 17.5 (178) [2540] QA7 = 44.4 (11.7) PB7 = 17.5 (178) [2540] QB7 = 24.1 (6.37)
PA8 = 20.0 (200) [2900] QA8 = 35.4 (9.35) PB8 = 20.0 (200) [2900] QB8 = 20.3 (5.36)
PA9 = 22.5 (229) [3260] QA9 = 26.5 (7.0) PB9 = 22.5 (229) [3260] QB9 = 18.5 (4.89)
PA10 = 25.0 (255) [3630] QA10 = 16.6 (4.39) PB10 = 25.0 (255) [3630] QB10 = 16.5 (4.36)
PA11 = 27.4 (279) [3970] QA11 = 14.7 (3.88) PB11 = 27.4 (279) [3970] QB11 = 14.6 (3.86)
CAUTION
• Measured values may vary depending on the machine.
• This data is of values converted to the rated RPM.
• The usage limit is 80% of the discharge volume.
RY9212166HYS0146US0
3-S171 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(3) AUX discharge flow rate data (measured values) [KX057-4, U55-4]
(1) P Mode (a) Pressure (MPa) (A) AUX1
(2) E Mode (b) Flow Rate (L/min) (B) AUX2
MPa 3.0 5.0 10 15 17.2
Pressure (kgf/cm2) (30) (51) (100) (150) (175)
[psi] [400] [730] [1400] [2200] [2490]
(A) 76 74 72 59 53
P mode
Flow L/min (20) (20) (19) (16) (14)
Rate (U.S. gal.) 75 72 53 39 33
E mode
(20) (19) (14) (10) (8.7)
MPa 3.0 5.0 10 15 17.2
Pressure (kgf/cm2) (30) (51) (100) (150) (175)
[psi] [400] [730] [1400] [2200] [2490]
(B) 37 36 34 18
P mode
Flow L/min (9.8) (9.5) (9.0) (4.8)
Rate (U.S. gal.) 37 36 34 13
E mode
(9.8) (9.5) (9.0) (3.4)
CAUTION
• Measured values may vary depending on the machine.
• This measurement data is of the values set for the maximum discharge flow rate. (limit = maximum)
RY9212166HYS0147US0
3-S172 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(4) Relief Pressure Table (Measured Values)
Item KX057-4, U55-4 Notes
Travel right main pressure (aTR) 27.0 ± 0.5 MPa
280 ± 5 kgf/cm2
Travel left main pressure (aTR) 3900 ± 73 psi
28.0 ± 0.5 MPa
Main LS pressure (aLS) 290 ± 5 kgf/cm2
4100 ± 73 psi
19.6 ± 0.5 MPa
Main P3 pressure (aP3) 200 ± 5 kgf/cm2
2840 ± 73 psi
3.0 ± 0.2 MPa
Unload LS valve pressure (aUN) 30 ± 2 kgf/cm2
440 ± 29 psi
4.2 ± 0.2 MPa
Pilot primary pressure (aPP) 43 ± 2 kgf/cm2
610 ± 29 psi
3.65 MPa
P mode 37.2 kgf/cm2
529 psi
2.8 MPa
EP mode solenoid pressure P mode (AC ON) 29 kgf/cm2 Compressor: ON
406 psi
0 MPa
E mode 0 kgf/cm2
0 psi
Bottom (b1B) 31.4 ± 1.0 MPa
Boom 320 ± 10 kgf/cm2
Rod (b1R) 4550 ± 145 psi
Bottom (b2B) 31.4 ± 1.0 MPa
Arm 320 ± 10 kgf/cm2
Rod (b2R) 4550 ± 145 psi
Bottom (b3B) 31.4 ± 1.0 MPa
Bucket 320 ± 10 kgf/cm2
Rod (b3R) 4550 ± 145 psi
27.4 ± 1.0 MPa
Blade Bottom (b4B) 279 ± 10 kgf/cm2
3970 ± 145 psi
Left (b6L) 19.0 ± 1.0 MPa
AUX1 190 ± 10 kgf/cm2
Right (b6R) 2800 ± 145 psi
19.0 ± 1.0 MPa Measurement points: pressure
Bottom (b8B) 190 ± 10 kgf/cm2 detection ports
2800 ± 145 psi
Angle
27.4 ± 1.0 MPa
Rod (b8R) 279 ± 10 kgf/cm2
4550 ± 145 psi
Left (b10L) 18.0 ± 1.0 MPa
Measurement location: pressure
AUX2 180 ± 10 kgf/cm2
test port
Right (b10R) 2600 ± 145 psi
Left (cSL) 21.0 ± 1.0 MPa
Measurement location: pressure
Swivel 210 ± 10 kgf/cm2
test port
Right (cSR) 3000 ± 145 psi
RY9212166HYS0105US0
3-S173 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(5) Motor Drain Volume (Measured Value)
Item KX057-4, U55-4 Notes
70 ml/min
When turning
4.0 cu.in./min
Swivel Motor
160 ml/min
When locked
9.8 cu.in./min
250 ml/min
When turning (1st speed)
15.0 cu.in./min
When turning 250 ml/min
Travel motor
(2nd speed) 15.0 cu.in./min
1100 ml/min
When locked (1st speed)
67 cu.in./min
RY9212166HYS0106US0
3-S174 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
(6) Performance reference list (quality standard values)
Item KX057-4 Notes
Ground to max.
2.7 ±0.3 sec
lift
Boom (CAB)
Max. lift to
3.2 ±0.3 sec
ground
Crowd 2.7 ±0.3 sec
Arm
Dump 2.7 ±0.3 sec
Crowd 2.9 ±0.3 sec
Bucket
Hydraulic cylinder Dump 2.0 ±0.3 sec
operation time Left 6.5 ±0.5 sec
Swing
Right 7.9 ±0.5 sec
Max down to
2.0 ±0.3 sec
Max up
Blade
Max up to Max
2.8 ±0.3 sec
down
Left 2.3 ±0.3 sec
Angle (Angle spec.)
Right 1.8 ±0.3 sec
≤ 20.0 mm
Std. when new
≤ 0.79 in.
Boom
≤ 100.0 mm
Usage limit
≤ 3.94 in.
≤ 20.0 mm
Std. when new
≤ 0.79 in.
Arm
≤ 100.0 mm
Usage limit
≤ 3.94 in.
Hydraulic cylinder drift
≤ 10.0 mm
Std. when new
≤ 0.39 in.
Bucket
≤ 50.0 mm
Usage limit
≤ 1.97 in.
≤ 20.0 mm
Std. when new
≤ 0.79 in.
Blade
≤ 70.0 mm
Usage limit
≤ 2.76 in.
≤ 5.0 mm
When stopped
≤ 0.20 in.
Swivel Block Performance
≤ 30.0 mm
When Idling
≤ 1.18 in.
Swivel speed 3 revs 17.8 to 21.6 sec
0 mm
Travel block performance
0 in.
1st 11.6 to 14.4 sec
Rubber
2nd 6.8 to 8.4 sec
Travel speed
1st 12.4 to 15.7 sec
Steel
2nd 7.1 to 8.8 sec
≤ 600.0 mm
Amount of travel drift
≤ 23.6 in.
RY9212166HYS0151US0
3-S175 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Item U55-4 Notes
Ground to max.
2.7 ±0.3 sec
lift
Boom (CAB)
Max. lift to
3.4 ±0.3 sec
ground
Crowd 2.6 ±0.3 sec
Arm
Dump 2.6 ±0.3 sec
Crowd 2.8 ±0.3 sec
Bucket
Hydraulic cylinder Dump 2.0 ±0.3 sec
operation time Left 6.5 ±0.5 sec
Swing
Right 7.9 ±0.5 sec
Max down to
2.0 ±0.3 sec
Max up
Blade
Max up to Max
2.8 ±0.3 sec
down
Left 2.3 ±0.3 sec
Angle (Angle spec.)
Right 1.8 ±0.3 sec
≤ 20.0 mm
Std. when new
≤ 0.79 in.
Boom
≤ 100.0 mm
Usage limit
≤ 3.94 in.
≤ 20.0 mm
Std. when new
≤ 0.79 in.
Arm
≤ 100.0 mm
Usage limit
≤ 3.94 in.
Hydraulic cylinder drift
≤ 10.0 mm
Std. when new
≤ 0.39 in.
Bucket
≤ 50.0 mm
Usage limit
≤ 1.97 in.
≤ 20.0 mm
Std. when new
≤ 0.79 in.
Blade
≤ 70.0 mm
Usage limit
≤ 2.76 in.
≤ 5.0 mm
When stopped
≤ 0.20 in.
Swivel Block Performance
≤ 30.0 mm
When Idling
≤ 1.18 in.
Swivel speed 3 revs 17.6 to 21.4 sec
0 mm
Travel block performance
0 in.
1st 11.6 to 14.4 sec
Rubber
2nd 6.8 to 8.4 sec
Travel speed
1st 12.4 to 15.7 sec
Steel
2nd 7.1 to 8.8 sec
≤ 600.0 mm
Amount of travel drift
≤ 23.6 in.
RY9212166HYS0152US0
3-S176 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
17. TROUBLESHOOTING
Front System Troubleshooting
All front operations slow or not moving
Reference
Cause Inspection point Remedy
page
Defect of the engine itself Engine speed measurement Adjust each engine part –
Insufficient hydraulic fluid volume Check hydraulic tank oil level Replenish the hydraulic fluid
G-15
or oil degradation and oil quality supply or change the oil
Suction line (suction filter) Inspect the suction line Wash the suction line
1-S19
blockage (suction filter) Replace the suction line
Pilot filter blockage Pilot filter blockage inspection Replace pilot filter –
Adjust, wash or replace pilot
Pilot relief valve faulty operation or Pilot primary pressure
relief valve 3-S158
poor pilot pump performance measurement
Replace pilot pump
Poor main relief valve operation or Main relief valve pressure Adjust, wash or replace main
3-S160
seating measurement relief valve
Poor unload valve operation or Control valve unload Wash unload valve seat
3-S164
seating pressure measurement surface or replace
Drop in control differential pressure Pump LS regulator spool Wash LS regulator spool
–
due to LS regulator spool stick inspection Replace LS regulator spool
Defective pump installation Pump installation coupling
Replace pump coupling 3-S4
coupling inspection
Pump drive shaft breakage Pump drive shaft inspection Replace shaft –
Pump internal parts wear or
Pump inspection Repair or replace pump –
damage
Either pilot valve right or left front does not move or is slow
Reference
Cause Inspection point Remedy
page
Pilot valve line filter blockage
Pilot valve line filter blockage Clean pilot filter line filter –
inspection
Pilot secondary pressure
Pilot valve disassembly,
Defective pilot valve measurement of applicable 3-S159
cleaning or replacement
cylinder
Low power of entire hydraulic system
Reference
Cause Inspection point Remedy
page
Adjust, wash or replace pilot
Pilot relief valve faulty operation or Pilot primary pressure
relief valve 3-S158
poor pilot pump performance measurement
Replace pilot pump
Poor main relief valve operation or Main relief valve pressure Adjust, wash or replace main
3-S160
seating measurement relief valve
Defective control differential
Pump LS regulator spool Wash LS regulator spool
pressure due to LS regulator spool –
inspection Replace LS regulator spool
stick
3-S177 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
A certain cylinder only does not move or is slow
Reference
Cause Inspection point Remedy
page
Pilot secondary pressure
Pilot valve disassembly,
Applicable pilot valve defect measurement of applicable 3-S159
cleaning or replacement
cylinder
Defective specified pressure of Inspection of overload relief Wash overload relief valve
3-S161
overload relief valve valve of applicable cylinder seat surface or replace
Inspection of control valve Control valve spool
Control valve spool stick –
spool of applicable cylinder disassembly and washing
Defective seal of cylinder internal Inspection of applicable Cylinder disassembly and
3-S61
parts cylinder seal replacement
Low power of certain implement
Reference
Cause Inspection point Remedy
page
Adjust, wash or replace pilot
Pilot relief valve faulty operation or Pilot primary pressure
relief valve 3-S158
poor pilot pump performance measurement
Replace pilot pump
Defective specified pressure of Inspection of overload relief Wash overload relief valve
3-S161
overload relief valve valve of applicable cylinder seat surface or replace
Disassemble and wash LS
Drop in control differential pressure Pump LS regulator spool
regulator spool –
due to LS regulator spool stick inspection
Replace LS regulator spool
Major front leak (drift) volume
Reference
Cause Inspection point Remedy
page
Defective specified pressure of Inspection of overload relief Wash overload relief valve
3-S161
overload relief valve valve of applicable cylinder seat surface or replace
Inspection of control valve Control valve spool
Control valve spool stick –
spool of applicable cylinder disassembly and washing
Defective seal of cylinder internal Inspection of applicable Cylinder disassembly and
3-S61
parts cylinder seal replacement
RY9212166HYS0148US0
3-S178 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Travel System Troubleshooting
No travel on one side. Slow Meandering
Reference
Cause Inspection point Remedy
page
Earth removal around crawler
Crawler tension trouble or earth Crawler tension and blockage
and crawler tension –
blockage around crawler inspection
adjustment
Travel pilot valve
Defective travel pilot valve Travel pilot valve secondary
disassembly, cleaning or 3-S84
operation pressure measurement
replacement
Defective travel relief specified Slow side travel relief Travel relief valve washing or
3-S160
pressure of control valve pressure measurement replacement
Control valve spool stick Control valve spool
Control valve spool stick –
inspection disassembly and washing
Travel motor counterbalance
Travel motor counterbalance
Control valve spool stick valve disassembly, cleaning 3-S32
spool inspection
or replacement
Travel motor drain volume Travel motor disassembly,
Defective travel motor 3-S32
measurement replacement
Remove the travel outlet hose
Internal leak of swivel joint of the swivel joint, plug it and Swivel joint seal replacement 3-S23
measure the relief pressure
RY9212166HYS0149US0
3-S179 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM HYDRAULIC SYSTEM
Swivel System Troubleshooting
Swivel speed low or no swivel
Reference
Cause Inspection point Remedy
page
Travel pilot valve secondary Pilot valve disassembly,
Defective pilot valve 3-S84
pressure measurement cleaning or replacement
Control valve swivel section
Swivel section spool stick Clean spool –
spool inspection
Defective swivel relief specified Swivel relief pressure Swivel relief valve washing or
3-S165
pressure measurement replacement
Swivel motor drain volume Swivel motor disassembly,
Internal defect of swivel motor 3-S12
measurement replacement
Snagging or sticking of friction Inspection for snagging or
plate for swivel motor parking sticking of friction plate for Replace friction plate 3-S12
brake swivel motor parking brake
Swivel drift
Reference
Cause Inspection point Remedy
page
Check that the pilot valve Pilot valve disassembly,
Pilot valve spool stick 3-S75
spool has returned to neutral cleaning or replacement
Control valve swivel section Control valve spool
Swivel section spool stick –
spool inspection disassembly and washing
Defective swivel relief specified Swivel relief pressure Swivel relief valve washing or
3-S165
pressure measurement replacement
Swivel motor make-up poppet stick Swivel motor make-up poppet Make-up poppet disassembly
3-S12
or defective seat surface inspection and washing
Swivel motor drain volume Swivel motor disassembly,
Internal defect of swivel motor 3-S12
measurement replacement
RY9212166HYS0150US0
3-S180 KiSC issued 04, 2021 A
4 ELECTRICAL SYSTEM
KiSC issued 04, 2021 A
SERVICING
CONTENTS
1. READING THE ELECTRICAL CIRCUIT DIAGRAMS .................................................................4-S1
[1] LAYOUT OF ELECTRICAL CIRCUIT DIAGRAMS ...............................................................4-S1
(1) Main Layout .....................................................................................................................4-S1
[2] LAYOUT OF CONNECTOR DIAGRAMS ..............................................................................4-S5
(1) Main Layout .....................................................................................................................4-S5
[3] PRECAUTIONS ON HANDLING ELECTRICAL CONNECTORS .........................................4-S7
2. LAYOUT OF ELECTRICAL EQUIPMENT AND CONNECTORS................................................4-S8
[1] COMPARTMENT ..................................................................................................................4-S8
[2] REAR BONNET...................................................................................................................4-S13
[3] RIGHT BONNET .................................................................................................................4-S15
[4] ENGINE AREA CONNECTORS .........................................................................................4-S17
3. TROUBLESHOOTING (START-UP EQUIPMENT VERSION)..................................................4-S19
4. INSPECTIONS ..........................................................................................................................4-S20
[1] POWER AND GROUND .....................................................................................................4-S20
[2] STARTING AND STOPPING DEVICE ................................................................................4-S23
5. INSTRUMENT PANEL OPERATING GUIDE............................................................................4-S26
[1] METER OPERATING UNIT ................................................................................................4-S26
(1) Names and Functions of Each Meter and Switch..........................................................4-S26
[2] OPERATING METHOD REFERENCE LIST .......................................................................4-S26
[3] DETAILS OF THE OPERATIONAL PROCEDURES ..........................................................4-S27
(1) Refer to the Hour Meter, Clock, Engine rpm, Water Temperature, and Fuel ................4-S27
(2) View Operating Information ...........................................................................................4-S27
(3) Checking Periodic Inspection Items ..............................................................................4-S30
(4) How to Set the Clock .....................................................................................................4-S31
(5) Switching-Over of the Items of “AM/PM · 24 Hours” .....................................................4-S31
(6) Anti-Theft Settings .........................................................................................................4-S32
(7) Auxiliary Port Operation.................................................................................................4-S33
[4] SERVICE DEALER SETTINGS ..........................................................................................4-S43
(1) Diagnosis.......................................................................................................................4-S44
(2) Setting ...........................................................................................................................4-S52
[5] LIST OF WARNING ALARM DISPLAYS.............................................................................4-S80
(1) Warning Display List......................................................................................................4-S80
(2) Warning Display List......................................................................................................4-S82
(3) Table of DPF Warnings .................................................................................................4-S84
(4) PM Clog Level and the State of the Machine ................................................................4-S85
(5) Table of Engine System Error Numbers........................................................................4-S88
6. TROUBLESHOOTING (METER PANEL EDITION) ..................................................................4-S89
[1] MACHINE RELATED SYSTEM...........................................................................................4-S89
(1) Engine Oil Pressure Errors............................................................................................4-S89
(2) Charging System Errors ................................................................................................4-S92
(3) Fuel Sensor Errors ........................................................................................................4-S95
(4) Water Mixed into Fuel....................................................................................................4-S99
(5) Engine System Errors..................................................................................................4-S101
[2] FRONT-END SYSTEMS ...................................................................................................4-S101
(1) Lever Lock System Errors ...........................................................................................4-S101
(2) Travel 2-Speed System Error ......................................................................................4-S107
[3] AUTO IDLING (AI) SYSTEM .............................................................................................4-S112
(1) Accelerator Sensor Errors ...........................................................................................4-S112
(2) Testing the AI Pressure Switch ...................................................................................4-S116
KiSC issued 04, 2021 A
(3) Testing the AI Switch ...................................................................................................4-S120
[4] ANTI-THEFT (AT) SYSTEM ..............................................................................................4-S124
(1) Anti-Theft System Errors .............................................................................................4-S124
[5] POWER SUPPLY SYSTEM ..............................................................................................4-S129
(1) Over Voltage................................................................................................................4-S129
(2) 5V Short System Error.................................................................................................4-S130
[6] COMMUNICATION SYSTEM ............................................................................................4-S131
(1) CAN Communication Errors ........................................................................................4-S131
[7] AUX SYSTEM....................................................................................................................4-S134
(1) AUX1 / AUX2/Thumb System Errors ..........................................................................4-S134
[8] ANGLE BLADE SYSTEM ..................................................................................................4-S139
(1) Angle Blade System Error ...........................................................................................4-S139
[9] EP SYSTEM ......................................................................................................................4-S144
(1) EP System Errors ........................................................................................................4-S144
7. DEALER SETTING MODE FLOWCHART ..............................................................................4-S150
KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
1. READING THE ELECTRICAL CIRCUIT DIAGRAMS
[1] LAYOUT OF ELECTRICAL CIRCUIT DIAGRAMS
(1) Main Layout
(a) Battery
(b) Fuses
(c) Basic structural components
(d) Sensors, etc. (input system)
(e) Machine ECU
(f) Solenoids, etc. (output system)
(g) Auxiliary equipment
(h) A/C
(i) Common rail engine system
(j) Basic direction of electrical flow
CAUTION
• Please note that some items do not conform to this layout.
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Electrical wiring chart symbols for harnesses and wires
Item (Example) Contents of illustration Reference
(a) Name of part Sensor, fuel
(b) Specification code All use (common) Table shown on circuit diagram
2
(c) Wire size 0.50 mm
(d) Wire color Black Wire color page
(e) Unit symbol Potentiometer with sliding contact Unit symbol page
(f) Pin name Earth
(g) Pin No. 2
(h) Connector name Sensor, fuel Connector diagram
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4-S1 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Colors of Wiring
Color of wiring Color code
Black B
Green G
Blue L
Pink P
Red R
White W
Yellow Y
Brown BR
Gray GY
Light Green LG
Orange OR
Sky Blue SB
(Ex.)
1.25-Y/R means :
1.25 : Wire size (mm2)
Y : Base color (yellow)
R : Stripe color (red)
• Do not pull on or step on wires. Also, do not cut wires on burred
edges or the like.
• Do not twist or pinch wiring when installing it.
(a) Wire Size (mm2) (c) Stripe Color
(b) Insulation Base Color
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4-S2 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Unit symbol
(1) Variable (10) Potentiometer with Sliding (18) Light-Emitting Diode (LED) (27) Buzzer
(2) Non-Linear Variable Contact (19) Two-Way Breakdown Diode (28) Horn
(3) Fixed Setting (11) Heating Element (20) Coil (29) Speaker
(4) Step Variable (12) Condenser (21) Normally Open Contact (30) A/C Voltage Source
(5) Non Ionizing Radiation (NIR) (13) Electrolytic Capacitor (22) Auto-Resetting Normally (31) Switch
(6) Body GND (14) Magnetic Core Inductance Closed Contact (32) OFF (No Auto-Reset)
(7) Thermistor (15) PNP Transistor (23) Auto-Resetting Normally (33) ON
(8) Resistor (16) NPN Transistor Open Contact (34) START (Auto-Reset)
(9) Variable Resistor (17) Semiconductor Diode (24) Relay Coil
(25) Fuse
(26) Lamp
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4-S3 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Bus bar markings
(A) Diagram Using Bus (B) Diagram Showing All
Circuits, Not Using Bus
1. Diagrams of circuits with a lot of junction branches, such as power supply circuits, are very complicated if depicted
literally, so a bus should be used where necessary.
2. A circuit is connected to both sides of the bus.
3. Wire attributes are used respectively for the circuits connected to both sides of the bus. (The circuits forming a
pair on each side of the bus must be connected.)
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Battery terminal and composite terminal markings
If terminals are fastened together, such as battery terminals
• Fasten terminals (2) and (3) together with one bolt.
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4-S4 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[2] LAYOUT OF CONNECTOR DIAGRAMS
(1) Main Layout
Connector arrangement sequence
In alphabetical order downwards from top left, and then to column next right.
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Depiction of Connectors
In principle, the connector locking part is shown on the top side.
Female connector terminal numbers start from 1 in the top right corner, looking at the connecting face.
Male connector terminal numbers start from 1 in the top left corner.
(A) Female Connector Terminal
(B) Male Connector Terminal
(C) Not Waterproofed
(D) Waterproofed
10 terminals or fewer Above-stated pin numbers in all cases. Numbers assigned according to numbering specifications.
Manufacturer's instructions given. Use manufacturer's stated pin numbers.
11 terminals or more Numbers assigned according to above-stated numbering
Manufacturer's instructions not given.
specifications.
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4-S5 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Sep- Waterproofed / No. of Sep- Sep- Identify- Sep- Sep-
Male / Com-
Group ara- Not Termi- ara- Housing ara- ing suf- ara- ara-
Female ment
tor waterproofed nals tor tor fix tor tor
O : Open (not 1234-5678-20 Alphanu-
waterproofed) F : Female Connector meric
8-pin " (" ")"
W: M : Male manufacturer's charac-
Waterproofed part no. ters
LA : Round
automotive F : Female
terminal
"_"
LE :
Claw-shaped
F : Female Hole dia. M○○
automotive
terminal
BA : Automotive
battery lead F : Female
terminal
CB : Female
F : Female
bullet terminal
Blank column
CA : Male bullet
M : Male
terminal
C
PA : Flat male Tab width 1-9→
(Connec- "_" "_"
embedded bullet 250 (6.3 mm) A-Z
tor) M : Male
terminal (w/out 187 (4.75 mm)
cover) 01 110 (2.8 mm)
Manufacturer's
O : Flat male
sleeve part no.
embedded bullet
M : Male (enter terminal
terminal (w/
part no. in
cover)
series column)
Manufacturer's
O : Flat female sleeve part no. "_"
bullet terminal F : Female (enter terminal
(w/ cover) part no. in
series column)
Tab width
PA : Flat female
250 (6.3 mm)
bullet terminal F : Female
187 (4.75 mm)
(w/out cover)
110 (2.8 mm)
M : Bolt
Starter, alternator power
embedded M : Male Bolt size : M○○
terminals, etc.
terminal
Example) C_WF08_1234-5678-20_1 (8-terminal waterproofed female connector)
If there is no manufacturer's connector part number, for instance, when there is a direct connector on the unit side,
then follow the method indicated below.
• Use the manufacturer's connector part number on the harness side.
• For the symbol indicating male/female, use the "M" or "F" on the unit-side connector.
• Put "DUMMY" in the comment column.
Example) C_WM02_7283-7027-40_1 (DUMMY) (A unit-side two-terminal waterproofed male connector
"KubotaPart No.: 1J574-59681 Sensor, Intake temperature")
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4-S6 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[3] PRECAUTIONS ON HANDLING ELECTRICAL CONNECTORS
1. When disconnecting connectors, grasp the body of the connector and pull it out; do not pull on the wiring harness.
If the connector is the locking type, release the lock and then pull to disconnect.
2. When removing a connector's plastic cover (for water protection) to inspect it, be careful not to let any water get
in the connector. If water does get in, dry it thoroughly before reassembling the connector and putting its plastic
cover securely in place.
3. Straighten any bent connector terminals and make sure none are sticking out or missing. Also make sure there
is no corrosion on the connector's terminals before connecting it.
4. When connecting a locking connector, be sure to press it in until you hear it click and then pull gently on the
harness close to the connector and make sure the harness does not come out.
RY9212001ELS0224US0
4-S7 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. LAYOUT OF ELECTRICAL EQUIPMENT AND
CONNECTORS
[1] COMPARTMENT
No. Name of part No. Name of part
(1) Cabin front worklight (16) Engine ECU
(2) AUX1 joystick lever (17) Meter panel
(3) Washer Motor (18) AUX2 joystick lever
(4) Lock lever switch (19) Horn switch
(5) Air Conditioning Unit (20) Key switch
(6) For extended functions (RS232C) (21) Accelerator pedal
(7) CAN communication (2P) (22) Worklight switch
(8) CAN communication (4P) (23) Beacon switch
(9) Fuel sensor (24) Eco mode switch
(10) Main ECU (25) DPF regeneration inhibitor switch
(11) Ground (26) Engine stop switch
(12) Travel pressure sensor (27) Travel 2-speed switch
(13) Horn (28) Angle blade switch
(14) Fuse box (29) A/C control panel
(15) Power socket (30) Wiper switch
RY9212166ELS0001US0
4-S8 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(4) Lock Level Switch Connector
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(6) Connector for Extended Functions (7) CAN Communication (2P)
(RS232C) Connector
(8) CAN Communication (4P)
Connector
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(9) Fuel Sensor Connector (34) Front Worklight Connector
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(11) Ground (13) Horn Connector
(12) Travel Pressure Sensor Connector
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(16) Engine ECU Connector
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4-S9 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(17) Meter Panel Connector (a) Electronic Buzzer Connector
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(18) AUX2 Joystick Lever Connector (23) Beacon Switch
(19) Horn Switch Connector (26) Engine Stop Switch
(20) Key Switch Connector (27) Travel 2-Speed Switch
(22) Worklight Switch (28) Angle Blade Switch
(33) Anti-Theft Antenna
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(21) Accelerator Dial Connector
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(24) Eco Mode Switch (a) A/C and Heater Controller
(25) DPF Regeneration Inhibitor Switch Connector
(30) Wiper Switch (b) Blower Switch Connector
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(31) Cab Power Connector (a) Blower Power Connector
(32) Wiper Power Connector (b) Blower Register Connector
(c) Servo Motor Connector
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4-S10 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Connector Shape
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4-S11 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. Names of the Terminal Signals of the Main ECU Connector (Harness Side)
Connector Connector Connector
Ter Ter Ter
min Signal Name min Signal Name min Signal Name
al al al
1 GND (motor) 28 AUX1 control knob 1 55 –
2 GND (load line) 29 AUX2 control knob 1 56 –
3 +12V (load line) 30 – 57 Travel 2-speed switch
4 – 31 Start signal input 58 –
5 – 32 – 59 +B power (direct input)
6 – 33 Glow relay 60 CAN-H
7 Accelerator angle sensor 34 – 61 TxD (main ECU)
8 – 35 – 62 Lever lock solenoid
9 – 36 – 63 Engine stop switch
10 GND (sensor) 37 LED (anti-theft) 64 –
11 +5V Power output (sensor) 38 LED (multipurpose) 65 Eco mode switch
12 AI self-holding relay 39 LED (AI mode) 66 Boom up switch
13 Anti-theft horn relay 40 Buzzer output 67 Lever lock switch
14 Travel alarm buzzer 41 +12V Power output 68 Left angle switch
15 – 42 Right AUX2 solenoid 69 AUX1 fix switch
16 AUX2 solenoid (return) 43 Left AUX2 solenoid 70 DPF regeneration inhibitor switch
17 Multipurpose solenoid relay 44 Worklight switch 71 Right angle switch
18 Right angle solenoid 45 Compressor clutch switch 72 AUX2 fix switch
19 AUX1 solenoid (return) 46 Starter switch 73 Multipurpose lever switch
20 Left angle solenoid 47 Eco mode display 74 Multipurpose switch
21 EP solenoid (return) 48 DPF regeneration inhibitor display 75 AI mode-switching switch
22 EP solenoid 49 TxD (anti-theft antenna) 76 A/C switch (key switch)
23 AUX left solenoid 50 AI pressure switch 77 –
24 AUX right solenoid 51 RxD (anti-theft antenna) 78 –
25 – 52 – 79 CAN-L
26 – 53 Travel pressure sensor 80 RxD (main ECU)
27 – 54 – 81 Travel 2-speed solenoid
RY9212166ELS0002US0
4-S12 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[2] REAR BONNET
No. Name of part No. Name of part
(1) DPF pressure differential sensor (11) Starter
(2) EGR valve (12) Fuel pump
(3) Injector (13) NE sensor
(4) Glow plug (14) Water temperature sensor
(5) Air flow sensor (15) Intake throttle valve
(6) Alternator (16) E/P solenoid
(7) Rail pressure sensor (17) Meter wake-up switch
(8) Oil switch (18) DPF outlet temperature sensor
(9) Fuel temperature sensor (19) DOC outlet temperature sensor
(10) SCV (20) DOC intake temperature sensor
• G sensor and compressor clutch located on rear side of engine.
RY9212166ELS0062US0
4-S13 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(16) E/P Solenoid Connector
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(17) Meter Wake-Up Switch Connector
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(12) Fuel Pump Connector
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Connector shape
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4-S14 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[3] RIGHT BONNET
No. Name of part No. Name of part
(1) AUX2 (R) solenoid (9) Angle (L) solenoid
(2) AUX2 (L) solenoid (10) Angle (R) solenoid
(3) AUXA (R) solenoid (11) Lever lock solenoid
(4) AUX1 (L) solenoid (12) Travel 2-speed solenoid
(5) Slow-blow fuses (13) Fuel filter (water vol. sensor)
(6) Battery (14) Fuel filter (heater)
(7) AI pressure switch (15) Compressor switch (dual pressure switch)
(8) Boom rise switch
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4-S15 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(7) AI Pressure Switch Connector (8) Boom Rise Switch Connector
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(11) Lever Lock Solenoid Connector (12) Travel 2-Speed Solenoid Connector
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Connector Shape
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4-S16 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[4] ENGINE AREA CONNECTORS
(1) Injector Connector (14) Oil Switch Connector
(2) Compressor Clutch Connector (15) Fuel Temperature Sensor
(3) Glow Plug Connector
(4) SCV Connector (16) Starter (+B)
(5) EGR Valve Connector (17) G Sensor Relay Connector
(6) Starter (50) (18) G Sensor Connector
(7) NE Sensor Connector (19) DPF Outlet Temperature Sensor
(8) Oil Switch Connector (White)
(9) Water Temperature Sensor (20) DOC Outlet Temperature Sensor
Connector Connector (Gray)
(10) Intake Throttle Valve Connector (21) DOC Inlet Temperature Sensor
(11) Rail Pressure Sensor Connector Connector (Black)
(12) Alternator (22) Air Flow Sensor Connector
(13) Alternator (+B)
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4-S17 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Connector Shape
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4-S18 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
3. TROUBLESHOOTING (START-UP EQUIPMENT
VERSION)
Engine does not start
Checkpoint Cause Solution
Check whether "Wrong Key" is
displayed when it is in the start
The engine was not started with the Start the engine with the registered
position. Determine whether it is the
registered key. key.
registered key or not in the tester
mode.
Is the unload lever up or not?
The lever lock switch (limit) is Lift the unload lever and then start
Is the message "Lift the lever"
pressed in. the engine.
displayed?
After determining the cause of
Slow-blow and/or other fuses are
Check slow-blow and other fuses. slow-blow and/or other fuses
blown.
blowing, replace them.
Check whether GND wire(s) are
Ground defective Tighten GND wire bolt(s).
securely connected to the body.
Check battery voltage and specific
Battery fault Recharge or replace the battery.
gravity.
Check continuity between key
Key switch faulty Replace the key switch.
switch terminals.
Repair the harness.
Measure the voltage at terminal B of Break in continuity of the harness or
Replace the harness, starter relay
the starter. starter relay.
and/or fuses.
Repair the harness.
Measure the voltage at terminal S of Break in continuity in the harness,
Replace the harness, starter relay
the starter. starter relay and/or fuses.
and/or fuses.
Disconnect the lever lock switch
Repair the harness.
(limit) connector and measure the Break in continuity in the harness or
Replace the harness and/or fuses.
voltage at the connector terminals lever lock switch (limit) fuses.
Replace the lever lock switch (limit).
on the harness side.
The engine fails to start sometimes.
Checkpoint Cause Solution
The fob and/or keyring are
Is the key on a metal keyring or
interfering with communication Get rid of the fob and/or ring.
have a metal fob?
between the key and the antenna.
Engine starts even with unregistered keys
Checkpoint Cause Solution
As the anti-theft function is not
Check whether the anti-theft system Make the anti-theft settings and
working, even unregistered keys
is "OFF" or not initialized. register the key.
can start the engine.
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4-S19 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
4. INSPECTIONS
[1] POWER AND GROUND
Slow-blow fuses
IMPORTANT
• When replacing a slow-blow fuse, always use the same
capacity fuse and replace it after determining why it blew.
(1) Slow-Blow Fuses
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Inspecting slow-blow fuses
• Measurement parameter: check continuity across its terminals
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(A) 80A Alternator
(B) 30A Engine ECU
(C) 50A Main Power (1)
(D) 50A Main Power (2)
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Fuses
IMPORTANT
• When replacing a fuse, always use the same capacity fuse
and replace it after determining why it blew.
(1) Fuse Box
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Inspecting fuses
• Measurement parameter: check continuity across its terminals
RY9212001ELS0031US0
4-S20 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Fuse capacity and their circuits
(1) Blower Motor (+B) (12) Starter
(2) A/C Controller (13) Fuel Pump
(3) ECU Main (POWER) (14) Relay
(4) Beacon (15) Lever Lock
(5) Inside Light (16) Alternator
(6) Meter (+B) (17) ECU Main (AC)
(7) Horn Switch (18) Power Socket
(8) Horn (19) Fuel Filter Heater
(9) ECU Main (+B) (20) Compressor
(10) Cab Worklight (21) Radio (AC)
(11) Front Worklight (22) Wiper, Washer
[Cap specifications (with A/C) only]
(1) Blower Motor (+B) (21) Radio (AC)
(2) A/C Controller (22) Wiper, Washer
(20) Compressor
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Precautions when a Fuse Blows
When a fuse blows, there are 2 potential causes. The first is
when an overload of current exceeds the rated amperage of the
fuse, blowing it; the other is when it blows due to a repetitive,
intermittent current.
These two cases can be readily recognized visually, so when a
fuses blows, take note of the following points.
1. When a fuse blows due to an overload of current exceeding its
rated capacity.
An overload current produces a blown fuse such as shown at
left (A).
You should not immediately replace a fuse that blows in this
way with a new one.
The fuse will just blow again when subjected to the overload
current, so first inspect the circuit for a short or a problem with a
device, then after fixing the problem, install a fuse of the same
capacity.
The purpose of the original fuse is to provide a margin of safety,
so never replace a fuse with one of a higher capacity.
If you replace a fuse with one of a higher capacity, it presents
the danger of a current overload damaging the electrical
device(s) and/or the wiring in the circuit before blowing the fuse.
2. When a fuse blows due to a repetitive, intermittent current.
A repetitive, intermittent current produces a blown fuse such as
shown at left (B). In general, this kind of blown fuse occurs after
a relatively long period of time, so it does not happen very often.
With this kind of blown fuse, it is OK to replace it with a fuse of
the same capacity.
(A) Fuse Blown by Current Overload (B) Fuse Blown by Thermal Fatigue
RY9212001ELS0032US0
4-S21 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Ground
Check whether GND wire(s) are securely connected to the
body.
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Battery
Check the voltage between the terminals
1. Connect a circuit tester between the (+) and (-) terminals of the
battery and measure the voltage across the terminals.
2. If the measurement is below factory specs, check the specific
gravity of the electrolyte.
Voltage between
Factory specification At least DC 12 V
terminals
Check the condition of terminal connections
1. Put an electrical load on the battery. (E.g.: Turn the key switch
to RUN and turn a worklight on.
2. Connect the (+) side if the circuit tester to the (+) terminal of the
battery and the (-) side of the circuit tester to the (+) battery
cable. Measure the voltage.
3. Connect the (-) side if the circuit tester to the (-) terminal of the
battery and the (+) side of the circuit tester to the (-) battery
cable. Measure that voltage.
4. If the measurements are greater than factory specs, check the
condition of the contacts at the terminals.
Voltage between
Factory specification Less than DC 0.1 V
terminals
(1) (-) Terminal (2) (+) Terminal
RY9212001ELS0034US0
4-S22 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[2] STARTING AND STOPPING DEVICE
Key switch
Checks
1. Remove the key switch's 3P connector.
2. Turn the key switch to the RUN position and then check the
continuity between the red / white wire terminal of the connector
on the key switch side and the red wire terminal on the
connector.
3. Turn the key switch to the START position and then check the
continuity between the black/white wire terminal of the
connector on the key switch side and the red wire terminal on
the connector.
Key switch circuit table
(1) Red / White (3) Red
(2) Black / White
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Starter
1. Power supply to terminal B
IMPORTANT
• The battery voltage always exists at terminal B of the
starter, so do not short it during inspection.
1. Connect the (+) side of the circuit tester to terminal B of the
starter and the (–) side to the body and measure the voltage.
2. If the measurement meets the factory spec, the harness
between the battery and terminal B is OK.
3. If the measurement is outside of factory specs, check the
condition of the battery cable (+) contact and that of the GND (–)
cable and the body.
Measured voltage Factory specification 11 to 14 V (battery voltage)
2. Power supply to starter's pull-in and holding coils
1. Remove the connector from the starter's S terminal.
2. Connect the (+) of the circuit tester to the connector on the
harness side and the (–) to the body.
3. Put the machinery operation lock lever in the lock position and
measure the voltage with the key switch held in the START
position.
If the measurement meets factory specs, the circuit from the
battery to the S terminal is OK (harness, key switch, auto-release
relay).
Measured voltage Factory specification 11 to 14 V (battery voltage)
(1) Terminal B (2) Terminal S
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Relay capacity and their circuits
(1) Power (40A) (6) Horn (20A)
(2) Glow (40A) (7) Beacon (20A)
(3) Blower (20A) (8) Starter (20A)
(4) Worklight (20A) (9) Compressor (20A)
(5) ECU (POWER) (20A) (10) Engine ECU (20A)
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Starter relay
Harness-side voltage
1. Turn the key switch OFF and remove the starter relay.
2. Turn the key switch to RUN and measure the voltage between
connector terminal 3 on the fuse box side and the body.
3. If the measurement meets factory specs, it is OK.
Measured voltage Factory specification 11 to 14 V (battery voltage)
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Starter relay test
1. Turn the key switch OFF and remove the starter relay.
2. Impress the battery voltage between relay terminals 3 and 5 and
check for continuity between relay terminals 1 and 2.
3. If the measurement meets factory specs, it is OK.
Between terminals Factory specification Continuity
(a) Relay Terminal 5 (c) Relay Terminal 2
(b) Relay Terminal 3 (d) Relay Terminal 1
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Power relay
Harness-side voltage
1. Turn the key switch OFF and remove the glow relay.
2. Turn the key switch to OFF and measure the voltage between
connector terminal 3 on the fuse box side and the body.
3. If the measurement meets factory specs, it is OK.
Measured voltage Factory specification 11 to 14V (battery voltage)
4. Turn the key switch to RUN and measure the voltage between
connector terminal 1 on the fuse box side and the body.
5. If the measurement meets factory specs, it is OK.
Measured voltage Factory specification 11 to 14 V (battery voltage)
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Power relay test
1. Turn the key switch OFF and remove the glow relay.
2. Measure the resistance between terminals 1 and 4.
3. Check for continuity between terminals 2 and 3.
Factory
Measured items (+) (–)
specification
Coil Terminal 1 Terminal 4 72 to 88 Ω
Contact Terminal 2 Terminal 3 No continuity
(a) Terminal 1 (c) Terminal 4
(b) Terminal 3 (d) Terminal 2
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Switch (limit) connector voltage
1. Remove the 2P connector of the lever lock switch (limit).
2. Turn the key switch to RUN and measure the voltage between
the connector terminal (blue/white) on the wire harness side and
the body.
3. If the measurement meets factory specs, it is OK.
Measured voltage Factory specification 11 to 14V (battery voltage)
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Switch (limit)
1. Remove the 2P connector of the limit switch.
2. Move the equipment lock lever up and down and check for
continuity between the connector terminals when the limit
switch is pressed and when it is free.
Key switch circuit table
(1) Limit Switch (3) Terminals (Black Wire)
(2) Connector
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5. INSTRUMENT PANEL OPERATING GUIDE
[1] METER OPERATING UNIT
(1) Names and Functions of Each Meter and Switch
Normal display
(1) User Settings Switch (Switch 1) (8) Hour Meter / Engine Tachometer
(2) Crane (Switch 2) (9) Eco Mode Mark (Displayed when in
(3) AUX Port Operation Switch Eco Mode)
(Switch 3) (10) Fuel Gauge
(4) Information Switch (Switch 4) (11) Warning Lights (Red, Yellow)
(5) Display Changing Switch (Switch 5) (12) Oil Lamp
(6) Clock Display (13) Charging Lamp
(7) Water Temperature Gauge (14) 2-Speed Lamp
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Displayed when menu selected
(1) Return Halt Settings and Return to (4) Forward Moves Selected Item
Original Screen. Forward.
(2) Down Move Selection Down One (5) Set/Select Sets the Selected Item.
Item. Moves Menu Selection Selects the Item in the Menu
Position Down. Selection Position.
(3) Up Move Selection Up One Item.
Moves Menu Selection Position Up.
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[2] OPERATING METHOD REFERENCE LIST
Refer-
Mode Operation items Operational procedures ence
Page
Refer to the Hour Meter, Clock, Engine Turn the key from OFF to ON.
Normal (1) 4-S27
rpm, Water Temperature, and Fuel (Pressing SW5 will change the display.)
Turn the key from OFF to ON and press SW1.
(2) Refer to the Operational Information 4-S27
Select "Log Record".
Turn the key from OFF to ON and press SW1.
(3) Periodic inspection 4-S28
Select "Periodic Check".
User Settings Turn the key from OFF to ON and press SW1.
(4) How to set the Clock 4-S31
Select "Clock Set".
Turn the key from OFF to ON and press SW1.
Switching-over of the items of
(5) Select "Various Settings" and select "Calender / 4-S31
"AM/PM · 24 hours"
Clock Set".
(Re-registers when the black key has Insert the red key in the key OFF and press SW1
Anti-theft settings (6) 4-S32
been lost) or SW5.
Turn the key from ON to OFF.
AUX port (7) AUX port operation 4-S33
Press SW3.
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[3] DETAILS OF THE OPERATIONAL PROCEDURES
(1) Refer to the Hour Meter, Clock, Engine rpm, Water Temperature, and Fuel
When the engine is started, the electronic meter display can be changed to three different display modes, by
pressing the display changing switch.
Starter key at [RUN] position.
(1)
(A)STOP, (B)RUN, (C)START
Press switch 5.
(2)
Press switch 5 to return to screen (2).
(3)
(a) Opening Screen
(b) While Glow Plugs On
(c) Hour Meter
(d) Tachometer (Numerical)
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(2) View Operating Information
The "Log Record" option can be used to check the last 3 months' operation of the machine.
Starter key at [RUN] position.
(1) (A)STOP, (B)RUN, (C)START
Press switch 1 (user settings).
(2)
Select "Log Record" and press switch 5.
(3)
Press switch 2 to see a work log (of the
days the machine was operated) for the last
(4)
month, and up to the month before last (90
days previous).
Operating time for month (bar graph
display)
(5)
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If a periodic check notification has been displayed
Check items are shown on the LCD screen at the corresponding hour meter time.
"Periodic Check Soon" is displayed 10
hours before the periodic check time.
(1)
Press switch 4 to verify the items to be
checked.
The displayed items are to be serviced.
(2)
NOTE
• When the periodic check time has passed, the notification
"Periodic Check Passed" is shown.
• After completing servicing, the check information display
is automatically cancelled when the key switch is turned on
and off 10 or more times.
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If the check items cannot all be displayed on one screen
Press the information switch (switch 4).
(1)
Pressing the cursor switches (switch 2 or 3) scrolls the check items up or
(2)
down.
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Periodic Check Items List (The following check items are displayed on the LCD screen at the corresponding
hour meter time.)
Hour meter indication
No. Check Item Measure Interval
50 100 250 500 600 750 1000 1500 2000
1 Engine oil (CJ-4) Change Every 500 hrs
2 Fuel filter Every 500 hrs
Replace
3 Engine oil filter Every 500 hrs
4 Drive unit oil Change Every 500 hrs
5 Breather filter Replace Every 500 hrs
6 Hydraulic oil Change Every 1000 hrs
Outer element Every 1000 hrs
7 Air filter element
Inner element Every 1000 hrs
8 Hydraulic return filter cartridge Replace Every 1000 hrs
9 Hydraulic suction filter element Every 1000 hrs
10 Pilot filter Every 1000 hrs
11 Idler, Track roller, Grease – Every 2000 hrs
12 DPF Replace Every 3000 hrs
First operation
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(3) Checking Periodic Inspection Items
Starter key at [RUN] position.
(A)STOP, (B)RUN, (C)START
(1)
Press switch 1 (user settings).
(2)
Press switch 2 to select "Periodic Check" and
then press switch 5.
(3)
[Periodic check item screen 1]
1st line : Item
2nd line : Next check time minus hour meter.
(4)
indicates negative value.
3rd line : Next check time
Press switch 2 to move to the next item.
[Periodic check item screen 2]
Press switch 2 to move to the next item.
(5) (Show all 12 items)
Press switch 3 to move to the last item.
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(4) How to Set the Clock
Starter key at [RUN] position.
(1)
(A)STOP, (B)RUN, (C)START
Press switch 1 (user settings).
(2)
(3) Press switch 2 to select "Clock Set".
(4) With "Clock Set" selected, press switch 5.
Set the clock and then press switch 5.
(5)
Setup complete
(6)
[Clock setting guide]
• Pressing switch 4 ( ) changes the setting item from Yr→ Mo→
Day→ Hr→ Min→ Yr.
• Pressing switch 2 ( ) reduces the number.
• Pressing switch 3 ( ) increases the number.
• Pressing switch 1 while on the clock setting screen takes the
screen back without changing the time.
NOTE
• The display shown left appears when the clock stops, due
to disconnection of the battery, etc. Press the Set switch
(switch 5) to set the clock again.
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(5) Switching-Over of the Items of “AM/PM · 24 Hours”
Starter key at [RUN] position.
(1)
(A)STOP, (B)RUN, (C)START
Press switch 1 (user settings).
(2)
Press switch 2 to select "Various Settings"
(3)
and then press switch 5.
Select "Calendar / Time display settings"
(4)
and then press switch 5.
Choose the display order: yyyy/mm/dd,
(5) dd/mm/yyyy, mm/dd/yyyy, and AM/PM or
24-hr display.
When the setting has been changed, press
(6) switch 5 to complete.
(a) Day/Month/Year Display
(b) Clock Display
(c) Cursor Movement Switches
(Switches 2 and 3)
(d) Item Movement Switch (Switch 4)
Scroll the selected item up and down with the cursor movement switches (switches 2 and 3), to change the
Year/Month/Day order on side (A). (This change is reflected in the Year/Month/Day order on the time adjustment
screen.)
Move the cursor to side (B) with the item movement switch (switch 4), and select either "AM/PM" or "24 hour".
Press the Set switch (switch 5) to make the changes and exit the procedure.
Press "Completed" with the direction cursor switch (switch 1) to exit without making changes.
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(6) Anti-Theft Settings
Registering the Black Key in the Machine
Insert the red key into the key switch.
(Leave key in without turning. If accidently moved to [RUN] position,
(1)
return to [STOP].
(a) Red key
Press the display changing switch once.
(2)
The meter panel shows [Pull out Key].
(3)
Remove the red key from the key switch.
(a) Red key
(4)
The meter panel shows [Insert Key].
(5)
Insert the black key into the key switch.
(Leave key in without turning. If accidently moved to [RUN] position,
(6)
return to [STOP], and repeat operation.
(b) Black key
After completing all of the registration steps, press the user setting
switch.
(7)
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(7) Auxiliary Port Operation
With a front-mounted digital meter, an optimal flow volume can be set for the AUX port, depending on the
attachment.
The flow can be set in 20 steps, left and right. Up to five patterns can be registered. When the attachment is
changed, the oil volume can be reset at a touch, by calling up the registered icon.
RY9212182ELS0046US0
[A] Selecting the Action Modes
The AUX port has been factory-set to four action modes. You can select one of them.
Up to six action modes can be preset. Each time the AUX port enable switch (switch 3) is pressed, the action modes
change over one after another. And the icon and action mode number on the screen change accordingly.
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AUX 1 mode only
[Mode 0] AUX disable (normal screen)
AUX 1 port : No activation
[Mode 1]
AUX 1 port : Max. flow volume
[Mode 2]
AUX 1 port : Limited flow volume
[Mode 3]
AUX 1 port : One way flow (Send oil to the port 2 only)
(1) No Lighting (3) Icon
(2) Blinking (4) Action Mode No.
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AUX 1 and 2 modes
[Mode 0] AUX disable (normal screen)
AUX 1 port : No activation
AUX 2 port : No activation
[Mode 1]
AUX 1 port : MAX. flow volume
AUX 2 port : MAX. flow volume
[Mode 2]
AUX 1 port : One way flow (Send oil to the port 2 only)
AUX 2 port : MAX. flow volume
(1) No Lighting (3) Icon
(2) Blinking (4) Action Mode No.
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NOTE
• When turning the starter key to the "RUN" position, the action mode will return to the last action mode
used.
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Checking the settings of each action mode
When an action mode is selected and the Information mark (2)
appears at the lower right of the icon, the flow volume setting gets
displayed by pressing the switch 4.
(1) Icon (3) Information Switch (Switch 4)
(2) Information Mark
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Display in AUX 1 and 2 modes
(1) Port 3 (3) Port 1
(2) Port 4 (4) Port 2
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[B] AUX Port Handling Procedure
1. Turn the starter key to the "RUN" position.
Let the engine warm up after start-up for approx. 10 minutes
under no load conditions.
(1) Starter Switch (A) "STOP"
(B) "RUN"
(C) "START"
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2. Lower the pilot control lock lever (UNLOCK).
(1) Pilot Control Lever (A) "Unlock"
(B) "Locked"
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3. Push the AUX port enable switch (switch 3).
NOTE
• If the pilot control lock lever is not at the "UNLOCK"
position, the following message appears on the screen.
Down this lever to the "UNLOCK" position first and then
press the AUX port enable switch (switch 3).
(1) AUX Port Enable Switch (Switch 3)
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4. [AUX1 only]
Move the AUX port knob of the right attachment control lever to
the right to send oil to the AUX port 1.
Move the AUX port knob to the left to send oil to the AUX port 2.
(1) Attachment Control Lever (Right) (a) "Port 1"
(b) "Port 2"
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5. [AUX1 and 2 models]
If the machine is equipped with the AUX 2 port, move the AUX
port knob of the left attachment control lever to the right to send
oil to the AUX port 1.
Move the AUX port knob of the left attachment control lever to
the left to send oil to the AUX port 2.
Move the AUX port knob of the right attachment control lever to
the right to send oil to the AUX port 3.
Move the AUX port knob of the right attachment control lever to
the left to send oil to the AUX port 4.
IMPORTANT
• Proportional control of the AUX port knob allows for
slow-to-fast movement of attachment.
Example : If you move the AUX port knob halfway, the
attachment will move at approximately one-half speed.
(1) Attachment Control Lever (Left) (a) "Port 1"
(2) Attachment Control Lever (Right) (b) "Port 2"
(c) "Port 3"
(d) "Port 4"
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One way hold
1. [AUX1 mode only]
Press the one way hold switch of the right attachment control
lever, and the oil continues to flow through the port 2.
(1) Attachment Control Lever (Right) (b) "Port 2"
(2) One Way Hold Switch (Right)
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2. [AUX1 and 2 modes]
Press the one way hold switch of the left attachment control
lever, and the oil continues to flow through the port (b).
Press this switch again or move the AUX port knob, and the oil flow
is interrupted.
NOTE
• Even if the one way hold switch of the right attachment
control lever is pressed, no function is assigned.
In this case, the following message appears on the screen.
(1) Attachment Control Lever (Right) (b) "Port 2"
(2) One Way Hold Switch (Right)
(3) Attachment Control Lever (Left)
(4) One Way Hold Switch (Left)
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[C] Setting the Maximum Flow Volume
The AUX port has been factory-set to three action modes 1, 2 and 3. The action modes 4 and 5 can also be preset.
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How to make the settings
1. With the starter key at the "RUN" position, press the user setting
switch (switch 1), and the following display appears on the
screen.
(1) User Setting Switch (Switch 1)
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2. Press the switch 2 or 3 to select "AUX Flow Ctr Set", and then
press the save switch (switch 5).
(1) Cursor Move Switch (2) Save Switch (Switch 5)
(Switch 2 and 3)
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3. Each time the switch 5 is pressed, the mode number changes.
Select your desired setting mode number.
(1) Icon (3) Switch 5
(2) Mode No.
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4. Take the following steps to set the icons. Each time the switch
4 is pressed, the setting cursor (arrow mark) shifts position.
Move the cursor above the icon.
(1) Setting Curcor (Arrow Mark) (3) Switch 4
(2) Icon
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5. Each time the switch 2 or 3 is pressed, the icon changes. Select
your desired icons.
(1) Icon (3) Switch 2
(2) Switch 3
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Types of AUX icons
NOTE
• There is no relationship between the icons and the flow
control settings. Select icons to suit the images of
attachments to be connected.
• In an action mode with the disable icon preset, such action
mode is skipped even if selected.
• Take an example of the following settings :
AUX (standard) icon for action mode 1,
Breaker icon for action mode 2,
Disable icon for actions modes 3, 4 and 5.
Each time the AUX port enable switch (switch 3) is pressed, the
display changes from action mode 1, action mode 2 to normal mode
in this order.
(a) AUX (Standard) (f) Clamshell
(b) Brush Cutter (g) Breaker
(c) Rotary Grapple (h) Tilt Bucket
(d) Grapple (i) Blank (Disable)
(e) Auger (j) Thumb
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[ Setting example ]
(a) Blank (Disable) Icon
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6. Set the maximum flow volume for each AUX port.
Press the switch 4 to move the setting cursor (arrow mark) to the
port 4 position of AUX2 at the right.
(1) Setting, Cursor (Arrow) (2) Switch 4
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(1) AUX 2 (a) "Port 1"
(2) AUX 1 (b) "Port 2"
(c) "Port 3"
(d) "Port 4"
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7. Press the switch 2 or 3 to preset the maximum flow volume. Set
the bar to the highest level, and the flow volume will be
maximized.
Set the bar to the lowest level (no bar displayed), and there will
be no oil flow.
Then press the switch 4 to go to the next port, and make the
settings for all the other ports.
NOTE
• Some attachments might not be activated even when the
bar level is still somewhat above the lowest position. Or
even when the bars of ports 1 and 2 (or of ports 3 and 4) are
at the same level, the same speed might not be achieved.
Those cases are not a machine failure, however. Readjust
the bar to the optimum level according to your
attachments.
• Suppose that the same attachment is mounted on another
machine. Even if the flow control setting is made, the same
speed cannot be achieved. Make an optimum setting on
each machine.
(1) Switch 2 (Lower Flow Volume) (A) "MAX. Flow Volume"
(2) Switch 3 (Higher Flow Volume) (B) "Output Interrupted"
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8. Go back to Step 3 to make settings for the next action mode.
When all the settings of all the action modes have been made,
press the switch 1 to return to the normal screen.
AUX port MAX. Flow volume
AUX2 port AUX1 port
MAX. flow volume (Theoretical) 37 75
L/min (U.S.gal/min) (9.87) (20)
17.2
MAX. pressure
(175)
MPa (kgf/cm2) [psi]
[2490]
IMPORTANT
• When the AUX port is not used for a long period, dirt
particles can settle in the lower part of the AUX port lines.
When the plugs on the AUX port lines are removed to
connect attachments, drain approx. 100 cc (3.4 oz) of oil
before making connections.
(1) Switch 1
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AUX port maximum flow volume setting flowchart
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Releasing Residual Pressure in the Hydraulic Circuit
Releasing Residual Pressure in the Front Machine
1. Place the machine and the blade on the ground.
2. Turn the starter key to the "STOP" position to switch off the
engine.
3. When the engine has stopped, turn the start key back to "RUN".
4. Put the machine operation lock lever in the [Unlock] position.
5. Move the machine operation lever to release the residual
pressure in the hydraulic circuit.
(1) Machine Lock Lever (A) Release
(B) Lock
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Releasing Residual Pressure in the AUX port
1. Place the machine and the blade on the ground.
2. Turn the starter key to the "STOP" position to switch off the
engine.
3. When the engine has stopped, turn the start key back to "RUN".
4. Put the machine operation lock lever in the [Unlock] position.
(1) Machine Lock Lever (A) Release
(B) Lock
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5. Set the AUX port operating switch to "ON".
(1) AUX Port Operating Switch
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6. Check that none of the AUX port flows are at minimum.
If residual pressure is expelled with the AUX port flow set to
minimum, then the residual pressure may not be expelled
completely and the hose connector may not detach.
(1) AUX Port Flow Display (A) AUX Port Flow Volume
(B) Max.
(C) Min.
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7. Move the AUX port switch connected to the machine operating
lever, left and right, to release the residual pressure in the AUX
port.
(B) AUX Port Flow at Maximum (C) AUX Port Flow at Minimum
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[4] SERVICE DEALER SETTINGS
Mode Operation Procedure
With the "SW5" switch pressed down, turn the main key from
[A] Tester
"OFF" to "ON". The tester mode appears on the screen.
Press "SW5" switch, turn main key from "OFF" to "ON", and
(1) Diagnosis [B] Investigating history of past failures
select "Retrieve Fail Record".
Press and hold the "SW5" switch, turn the main key from
[C] Deleting the fail record
"OFF" to "ON", and select "Delete Fail Record".
Press and hold the "SW5" switch, turn the main key from
[A] AI
"OFF" to "ON", and select "AI set".
Press and hold the "SW5" switch, turn the main key from
[B] Changing knob
"OFF" to "ON", and select "AUX1 Set".
(With attachment) Setting the start point. Start up the engine
[C] Attachment settings
AUX1 or raise the lock lever
[D] Header pressure rise (Without attachment) Setting the start point.
Press and hold the "SW5" switch, turn the main key from
[E] Feeling adjustment
"OFF" to "ON", and select "Feeling adjustment".
Press and hold the "SW5" switch, turn the main key from
[F] Changing knob
"OFF" to "ON", and select "AUX2/Thumb".
(With attachment) Setting the start point. Start up the engine
AUX [G] Attachment settings
or raise the lock lever.
2/Thumb
[H] Header pressure rise (Without attachment) Setting the start point.
Press and hold the "SW5" switch, turn the main key from
[I] Feeling adjustment
"OFF" to "ON", and select "Feeling adjustment".
Press and hold the "SW5" switch, turn the main key from
[J] Over load warning
"OFF" to "ON", and select "Over load warning".
(2) Settings Press and hold the "SW5" switch, turn the main key from
[K] Model (ECU and digital changed)
"OFF" to "ON", and select "Model Set".
1. Switching off periodic check guidance.
2. Need for periodic check guidance display
3. Periodic check offset time
[L] Other 4. Switching clock adjustment guidance display on/off.
5. Setup procedure for switching annual check guidance
display on/off.
6. Retrieving entire fail record.
[M] Use the AUX1 knob to control AUX2/Thumb (use the Press and hold the "SW5" switch, turn the main key from
AUX2/Thumb knob to control AUX1) "OFF" to "ON", and select "Exchange (AUX1, AUX2/Thumb)".
Press and hold the "SW5" switch, turn the main key from
[N] Conditions for changing the multipurpose switch.
"OFF" to "ON", and select "Multipurpose".
[O] Meter and ECU change timings If check made.
[P] Resetting the clock after disconnection of the battery If clock is reset.
Registering the black key of the machine. (If black key has
[Q] Anti-theft device
been lost)
[R] Overheat warning Setting the water temperature valve.
: Not used in North American spec.
RY9212166ELS0018US0
4-S43 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(1) Diagnosis
[A] Tester
Using the tester mode to check information about the sensor statuses and switches.
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Diagnosis" and press switch 5.
(3)
Select "Tester" and press switch 5.
(4)
To [Screen 1]
(a)
RY9212182ELS0068US0
[Screen 1]
Item Description/std. value
When engine stopped: 0
Engine RPM
Engine RPM: 1050 rpm
Battery voltage Battery voltage ±0.5V
Before engine start: ON
Oil
After engine start: OFF
Before engine start: ON
Charge
After engine start: OFF
Ket to START position : ON
Starter
Other position : OFF
RY9212182ELS0019US0
[Screen 2]
Item Description/std. value
Water temperature voltage Show voltage and temperature
0°C→ 4.38 V, 100°C → 0.91 V
Water Temperature (°C) (See table below for details)
Fuel voltage E : High, F : Low
Full tank (F) : 5Ω or lower
Fuel resistance
Empty (E) : 101.0Ω or lower
SW close to fuel filler port. ON when switch
Fuel supply SW
pressed.
RY9212166ELS0019US0
Fuel dot number
Design Value KX057-4 U55-4
Full 5Ω or less
1/2 full 34.65 Ω 33.64 Ω
3 dots left * 96.92 Ω 92.5 Ω
Empty 101.0Ω or higher
* Fuel warning
RY9212166ELS0020US0
4-S44 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[Screen 3]
Item Description/std. value
2-speed SW Press switch: ON
2-speed solenoid Solenoid : ON/OFF
Lever lock SW Press switch: ON
Lever lock solenoid Solenoid : ON/OFF
Oil temperature sensor Not used (not used currently)
RY9212166ELS0021US0
[Screen 4]
Item Description/std. value
Current value: (0.25 to 4.75V)
Accelerator POT
Set value : Idle (Low), Max (High)
Current value: (0.25 to 4.75V)
Governor POT
Set value : Idle (Low), Max (High)
AI motor operating: 0.0 to 15.0A
Motor amperage
AI motor stopped: 0.0 to 2.0.0A
RY9212182ELS0022US0
[Screen 5]
Item Description/std. value
Operation idle : ON
AI pressure SW
Operating: OFF
AI operating SW Press switch: ON
Compressor Operating: ON
Displays voltage and temperature 0°C ->
Water temperature
4.38V, 100°C -> 0.91V
Idle up Idle up set value
RY9212182ELS0023US0
[Screen 6]
Item Description/std. value
Current value: (0.25 to 4.75V)
AUX1 Set value : Left (Low), Right (High)
Set value: neutral (centre)
Operating: 0.5 to 2.0A
Amperage
Stopped: 0 to 0.2A
AUX hold SW Press switch: ON
RY9212182ELS0070US0
[Screen 7]
Item Description/std. value
Current value: (0.25 to 4.75V)
AUX2/Thumb knob Set value : Left (Low), Right (High)
Set value: neutral (centre)
Operating: 0.5 to 2.0A
Amperage
Stopped: 0 to 0.2A
AUX hold SW Press switch: ON
RY9212182ELS0071US0
4-S45 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[Screen 8]
Item Description/std. value
AUX1 R Set
AUX1 L Set
AUX start point set value
AUX2 Thumb R Set
AUX2 Thumb L Set
RY9212182ELS0072US0
[Screen 9]
Item Description/std. value
Arm POT Current value: (0.25 to 4.75V)
Arm limit set value Arm limit set value (see table below)
Arm limit setting solenoid Output : ON, Stopped : OFF
Design Value
Arm crowd 1.04 ±0.28 V
Arm dump 4.23 ±0.28 V
RY9212182ELS0024US0
[Screen 10]
Item Description/std. value
Antenna normal
Anti-theft antenna
Antenna malfunction: X
Key present , Anti-theft mode
Present/Absent, ON/OFF
Key absent X, anti-theft off X
Matching red key , Matching black key
Red key, Black key Non-matching red key X,
Non-matching black key X
Matching yellow key ,
Matching green key
Yellow or green key
Non-matching yellow key X,
Non-matching green key X
Matching yellow key ,
Matching green key
(Tag) yellow or green
Non-matching yellow key X,
Non-matching green key X
RY9212182ELS0025US0
[Screen 11]
Item Description/std. value
Angle right SW
Press switch: ON
Angle left SW
Angle right solenoid
Output : ON, Stopped : OFF
Angle left solenoid
RY9212182ELS0026US0
4-S46 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[Screen 12]
Item Description/std. value
Tilt right SW
Press switch: ON
Tilt left SW
Tilt right solenoid
Output : ON, Stopped : OFF
Tilt left solenoid
RY9212182ELS0073US0
[Screen 13]
Item Description/std. value
Actual load
Rated load
Current value
Radius
Height
Travel pressure sensor Current value (MPa)
RY9212182ELS0027US0
[Screen 14]
Item Description/std. value
Current value: (0.25 to 4.75V)
Arm POT Set value: Arm crowd (low) Arm dump end
(high)
Current value: (0.25 to 4.75V)
Boom POT
Set value: boom up end (high)
Bottom pressure, rod pressure Current value: (0.50 to 4.50V)
Design Value
Arm crowd 1.04 ±0.28 V
Arm dump 4.23 ±0.28 V
Boom up 4.22 ±0.28 V
RY9212182ELS0028US0
[Screen 15]
Item Description/std. value
Current value (V)
Boom bottom pressure
Current value (MPa)
Warning pressure Current value (MPa)
Current value (V)
Boom rod pressure
Current value (MPa)
RY9212182ELS0074US0
[Screen 16]
Item Description/std. value
Multipurpose switch 1 SW
Press switch: ON
Multipurpose switch 2 SW
Multipurpose switch solenoid Output : ON, Stopped : OFF
RY9212182ELS0075US0
4-S47 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[Screen 17]
Item Description/std. value
Compressor ON when operating
Boom up pressure SW Output : ON, Stopped : OFF
EP SW Press switch: ON
Pump solenoid Current amperage (A)
Amperage in pump solenoid (reference value)
KX057-4 U55-4
E2 1650 mA
E1 940 mA
AC 600 mA
P1 0 mA
E2 (E mode) Other than following modes
E1 (E mode) During travel or boom up operation
AC (P mode) A/C ON
P1 (P mode) A/C OFF
RY9212166ELS0022US0
[Screen 18]
Item Description/std. value
Current value (V)
Travel pressure sensor
Current value (MPa)
DPF SW Press switch: ON
Worklight SW Press switch: ON
Engine stop SW Press switch: ON
RY9212182ELS0077US0
[Screen 19] Japan RX Spec. only Sensor / Switch mounted
Item Description/std. value
Boom POT
Arm POT Current value: (0.25 to 4.75V)
Offset POT
Set Boom Arm Set value: boom up (high), arm crowd (low)
Set OFF Set value: offset right (high)
Design Value
Arm crowd 1.41 ±0.28 V
Boom up 4.38 ±0.28 V
Offset right 3.37 ±0.28 V
RY9212182ELS0029US0
[Screen 20] Japan RX Spec. only Sensor / Switch mounted
Item Description/std. value
Boom solenoid
Stopped: 0.0 to 0.6A
Arm dump/crowd
Operating: 0.4 to 1.2 A
Offset solenoid
Set ArD ArC Start point setting: arm dump, arm crowd
Set Bo Of Start point setting: boom up, offset right
RY9212182ELS0030US0
4-S48 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[Screen 21] Japan RX Spec. only Sensor / Switch mounted
Item Description/std. value
Emergency SW Press switch: ON ON
Boom up pressure SW Boom up operation : ON
Boom height limit Normal : ON; At height limit: OFF
RY9212182ELS0031US0
[Screen 22]
Item Description/std. value
Meter If correct, (If no meter, )
ECU (main) If correct, (If no ECU (main), )
ECU (AS) If RX→, U→X, KX→X (If no ECU(AS), )
Common rail →
ECU (CRS)
No common rail →X
RY9212182ELS0032US0
[Screen 23]
Item Description/std. value
Meter (Empty)
Ver Program version
Rev Program creation date (Y/M/D)
Serial No. Serial no. (different number each machine)
RY9212182ELS0033US0
[Screen 24]
Item Description/std. value
ECU (main) (Empty)
Ver Program version
Rev Program creation date (Y/M/D)
Serial No. Serial no. (different number each machine)
RY9212182ELS0034US0
[Screen 25]
Item Description/std. value
ECU (AS) (Empty)
Ver Program version
Rev Program creation date (Y/M/D)
Serial No. Serial no. (different number each machine)
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4-S49 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Return to original display
RY9212182ELS0036US0
CAUTION
• Indication does not disappear even if you turn off the key in
the tester mode.
When it is completed, press SW1, and get out of tester
mode.
(When you turn off the key and leave if as tester mode,
indication disappears three minutes later.)
RY9212182ELS0037US0
[B] Reading the Failure History
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Diagnosis" and press switch 5.
(3)
Select "Retrieve fail record" and press
(4) switch 5.
Display screen if there is no fail record
(5)
Fail record display screen.
(6)
(a) Shows ECU where a Failure has been
Detected. (Main) (Meter) Related Part
(b) Number of Occurrences (1 to 255)
(c) First Occurrence Date (Day/Month/Year) and
Hour Meter Reading, and Last Occurrence
Date (Day/Month/Year) and Hour Meter
Reading.
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4-S50 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[C] Erasing Failure History
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Diagnosis" and press switch 5.
(3)
Select "Delete fail record" and press switch
(4) 5.
Deletion of the fail record completed.
(5)
RY9212182ELS0079US0
Fail record reference list and causes/countermeasures
ECU No. Reason detected/steps to take
Engine Oil Pressure Errors Fall in engine oil pressure detected. Defective oil switch or harness : repair or replace.
Low alternator voltage detected. Defective alternator or harness, or loose fan belt:
Charging System Errors
repair or replace.
Overheating Overheating occurs.
Meter
Fuel sensor Fuel sensor error or harness defect.
CAN system (main) Defective harness or ECU (main).
Settings data error Reset model type. If not resolved, the meter is defective.
CAN Sys (CRS) Defective harness or ECU (CRS)
Lever lock solenoid Lever lock solenoid error or harness defect.
2-speed solenoid 2-speed solenoid error or harness defect.
Multipurpose solenoid Multipurpose solenoid error or harness defect.
AUX1 knob AUX1 knob error or harness defect.
AUX1 right solenoid AUX1 right solenoid error or harness defect.
AUX2 left solenoid AUX1 left solenoid error or harness defect.
AUX2/Thumb knob AUX2 knob error or harness defect.
AUX2/Thumb right solenoid AUX2 right solenoid error or harness defect.
AUX2/Thumb left solenoid AUX2 left solenoid error or harness defect.
Main External 5V External 5V in sensor system shorted to GND.
Oil temperature sensor Not used. (Not used at present.)
Over voltage Started at 24V. Or alternator faulty.
Travel pressure sensor Travel pressure sensor error or harness defect.
Angle blade right solenoid Angle blade right solenoid error or harness defect.
Angle blade left solenoid Angle blade left solenoid error or harness defect.
Boom Pot Boom Pot error or harness defect
Accelerator sensor Accelerator sensor error or harness defect.
EP solenoid EP solenoid error or harness defect.
Antenna Anti-theft antenna defect or harness defect
RY9212166ELS0049US0
4-S51 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(2) Setting
[A] AI Setting
Setup procedure required when the accelerator dial is changed
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Press switch 2 to select "Setting" and then
(3) press switch 5.
Select "AI Set" and press switch 5.
(4)
This screen is displayed if set to "Not AI
(5) spec." by the model settings.
From here, follow instructions on panel
(a) to complete settings.
Set the accelerator to [MAX] and press
(6) Switch 5.
Set the accelerator to idling and press
(7) Switch 5.
Procedure rapidly completed.
(b)
RY9212166ELS0024US0
4-S52 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[B] AUX1 Setting (Knob Exchanged)
Setup for knob (AUX1) when exchanging AUX1 knob
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Select "AUX1 Set" and press switch 5.
(4)
Select "Knob Set (AUX1)" and press switch
(5) 5.
Turn the AUX1 knob to the right end and
(6) press switch 5.
Turn the AUX1 knob to the left end and
(7) press switch 5.
Turn the AUX1 knob to neutral and press
(8) switch 5.
[Setup complete]
(9)
If AUX1 set to "Not AUX Spec." by model
(a) settings.
RY9212182ELS0081US0
4-S53 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[C] AUX1 Setting (with Attachment)
If the AUX1 proportionating valve or spool is changed:
Setup mode with light-load attachment fitted, such as thumb. If not available, can also be used with bucket.
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Select "AUX1 Set" and press switch 5.
(4)
Select "(w/ Attach) Set" and press switch 5.
(5)
When messages are displayed, follow the
relevant instructions.
(6)
(a): Raise lever lock
(b): Start engine
(c): Lower lever lock
Set the accelerator to [MAX], move the
attachment to the indicated position, and
(7)
press Switch 5.
When the attachment has moved left, press
(8) switch 5.
When the attachment has moved right,
(9) press switch 5.
[Setup complete]
(10)
If AUX1 set to "Not AUX Spec." by model
(d) settings.
RY9212182ELS0082US0
4-S54 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[D] AUX1 Setting (Pressure Rise of Header)
If the AUX1 proportionating valve or spool has been changed, a pressure rise is set for the pressure header.
This is a fine adjustment made when an attachment is not available.
1. Place a lid on both AUX port outlets and connect a pressure gauge.
2. Adjust each side and when both pressures have risen suddenly, press SW5 to set.
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Select "AUX1 Set" and press switch 5.
(4)
Select "(w/out Attach) Set" and press switch
(5) 5.
When messages are displayed, follow the
relevant instructions.
(6)
(a): Raise lever lock
(b): Start engine
(c): Lower lever lock
Set the accelerator to [MAX], move the
attachment to the indicated position, and
(7)
press Switch 5.
When the SP port (left) pressure rises
(8) suddenly, press switch 5.
When the SP port (right) pressure rises
(9) suddenly, press switch 5.
[Setup complete]
(10)
If AUX1 set to "Not AUX Spec." by model
(d) settings.
RY9212182ELS0083US0
4-S55 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[E] AUX1 Setting (Feeling Adjustment)
Setup for changing feeling of AUX1
Mode for unexpected situations where the adjustment for operating with or without an attachment has not been
successful and manual correction is required. The existing set values can be changed directly by operating the
buttons.
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Select "AUX1 Set" and press switch 5.
(4)
Select "Feeling Adj." and press switch 5.
(5)
When messages are displayed, follow the
relevant instructions.
(6)
(a): Raise lever lock
(b): Start engine
(c): Lower lever lock
Change the numerical values, while
continually checking the feeling, and press
(7)
switch 5.
[Setup complete]
(8)
If AUX1 set to "Not AUX Spec." by model
(d) settings.
RY9212182ELS0084US0
4-S56 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[F] AUX2 / Thumb Setting (Knob Exchanged)
Knob (AUX2/Thumb) setup when AUX2/Thumb knob is changed
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Select "AUX2/Thumb Set" and press switch
(4) 5.
Select "Knob Set (AUX2/Thumb)" and
(5) press switch 5.
Turn the AUX2 knob to the right end and
(6) press switch 5.
Turn the AUX2 knob to the left end and
(7) press switch 5.
Turn the AUX2 knob to neutral and press
(8) switch 5.
[Setup complete]
(9)
If AUX2/Thumb set to "Not AUX Spec." by
model settings.
(a)
RY9212182ELS0085US0
4-S57 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[G] AUX2 Setting (with Attachment)
If the AUX2/Thumb proportionating valve or spool is changed:
Setup mode with light-load attachment fitted, such as thumb. If not available, can also be used with bucket.
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Select "AUX2/Thumb Set" and press switch
(4) 5.
Select "(w/ Attach) Set" and press switch 5.
(5)
When messages are displayed, follow the
relevant instructions.
(6)
(a): Raise lever lock
(b): Start engine
(c): Lower lever lock
Set the accelerator to [MAX], move the
attachment to the indicated position, and
(7)
press Switch 5.
When the attachment has moved left, press
(8) switch 5.
When the attachment has moved right,
(9) press switch 5.
[Setup complete]
(10)
If AUX2/Thumb set to "Not AUX Spec." by
(d) model settings.
RY9212182ELS0086US0
4-S58 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[H] AUX2 / Thumb Setting (Pressure Rise of Header)
If the AUX2/Thumb proportionating valve or spool has been changed, a pressure rise is set for the pressure
header.
This is a fine adjustment made when an attachment is not available.
1. Place a lid on both AUX port outlets and connect a pressure gauge.
2. Adjust each side and when both pressures have risen suddenly, press SW5 to set.
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Select "AUX2/Thumb Set" and press switch
(4) 5.
Select "(w/out Attach) Set" and press switch
(5) 5.
When messages are displayed, follow the
relevant instructions.
(6)
(a): Raise lever lock
(b): Start engine
(c): Lower lever lock
Set the accelerator to [MAX], move the
attachment to the indicated position, and
(7)
press Switch 5.
When the SP port (left) pressure rises
(8) suddenly, press switch 5.
When the SP port (right) pressure rises
(9) suddenly, press switch 5.
[Setup complete]
(10)
If AUX2/Thumb set to "Not AUX Spec." by
(d) model settings.
RY9212182ELS0087US0
4-S59 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[I] AUX2 / Thumb Setting (Feeling Adjustment)
Setup for changing feeling of AUX2/Thumb
Mode for unexpected situations where the adjustment for operating with or without an attachment has not been
successful and manual correction is required. The existing set values can be changed directly by operating the
buttons.
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Select "AUX2/Thumb Set" and press switch
(4) 5.
Select "Feeling Adj." and press switch 5.
(5)
When messages are displayed, follow the
relevant instructions.
(6)
(a): Raise lever lock
(b): Start engine
(c): Lower lever lock
Change the numerical values, while
continually checking the feeling, and press
(7)
switch 5.
[Setup complete]
(8)
If AUX2/Thumb set to "Not AUX Spec." by
(d) model settings.
RY9212182ELS0088US0
4-S60 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[J] Overload Warning Setting
Setup for "Over load warning pressure (EU spec.)"
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Select "Over Load Warning" and press
(4) switch 5.
Enter the warning pressure number and
press switch 5.
(5)
Press switch 5.
(6)
[Setup complete]
(7)
If Over load warning set to not available by
(a) model settings.
RY9212182ELS0089US0
4-S61 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[K] Model Setting
Setup procedure required when changing the ECU or meter
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Press switch 2 to select "Model Set" and
(4) then press switch 5.
Press switch 2 to select "Model" and then
(5) press switch 5.
Select "Country name" and press switch 5.
(6)
Select "AI YES or NO" and press switch 5.
(7)
Select "Over load warning YES or NO" and
(8) press switch 5.
Select AUX1 spec. "Hand (Yes)" and press
(9) switch 5.
Select AUX2/Thumb spec. "Hand (Yes)"
(10) and press switch 5.
Select the Arm control spec. "YES or NO"
(11) and press switch 5.
Select "YES" if there is an angle blade and
(12) "NO" if there is no angle blade, and then
press switch 5.
Select "YES" if there is a tilt blade and "NO"
(13) if there is no tilt blade, and then press
switch 5.
Select "Multipurpose Operating YES or NO"
(14) and press switch 5.
Select "Arm Type" and press switch 5.
(15)
Select "Compartment Type" and press
(16) switch 5.
Select "Force mode" and press switch 5.
(17)
Select "Common Rail System YES or NO"
(18) and press switch 5.
[Setup complete]
(19)
RY9212182ELS0090US0
4-S62 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Example settings for KX057-4 and U55-4
Screen
Content displayed Notes
No.
(5) Select Model KX057-4 U55-4
America
(6) Select destination
Canada
(7) Select AI Yes/No Standard equipment, so select YES
(8) Select Over Load Warning Yes/No Set to NO.
(9) Select AUX-1 Yes/No Set to YES
(10) Select AUX-2/Thumb Yes/No Set to YES for AUX2 spec.
(11) Select Arm Control Yes/No Set to NO
(12) Select Angle Yes/No Set to YES for Angle spec.
(13) Select Tilt Yes/No Set to YES for Tilt spec.
(14) Select Multipurpose Switching Yes/No Set to NO when shipped
(15) Select arm spec. Set to 2
(16) Select compartment spec. Set to canopy or cab
(17) Select horsepower control mode Set to 1
(18) Select common rail system Yes/No Set to YES
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[L] Others
1. Clearing Periodic Check Guidance
Setup procedure for changing method of clearing periodic check guidance
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Press switch 2 to select "Setting" and then
(3) press switch 5.
Press switch 2 to select "Others" and then
(4) press switch 5.
Press switch 2 to select "Clear Periodic
(5) Check Guidance" and then press switch 5.
Select "Auto" or "Manual" and press switch
(6) 5. (Set to Auto on shipment)
[Setup complete]
(7)
Method of clearing periodic check guidance
• Turn key on and off ten times.
• At the question "Periodic Check
[Auto]
completed?" on the periodic check
screen, press "Yes".
• At the question "Periodic Check
completed?" on the periodic check
[Manual] screen, press "Yes".
• (Screen is not cleared by switching
key on and off.)
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4-S63 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. Switching periodic check guidance display on/off
Setup procedure for switching display of periodic check guidance on/off
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Press switch 2 to select "Setting" and then
(3) press switch 5.
Press switch 2 to select "Others" and then
(4) press switch 5.
Press switch 2 to select "Periodic Check
(5) Guidance Display" and then press switch 5.
Select "On / Off " and press switch 5.
(6)
[Setup complete]
(7)
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3. Periodic check offset time
Procedure for entering operating time in new meter after replacement
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Press switch 2 to select "Setting" and then
(3) press switch 5.
Press switch 2 to select "Others" and then
(4) press switch 5.
Press switch 2 to select "Adjust Periodic
Check Offset Time" and then press switch
(5)
5.
Set the hour meter to the reading before
(6) replacement and press switch 5.
[Setup complete]
(7)
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4-S64 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
4. Clock adjustment guidance display
Setup procedure for switching off clock setup warning
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Press switch 2 to select "Setting" and then
(3) press switch 5.
Press switch 2 to select "Others" and then
(4) press switch 5.
Select "Clock Set Warning" and press
(5) switch 5.
Select "On / Off " for the clock adjustment
(6) guidance and press switch 5.
[Setup complete]
(7)
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5. Setup procedure for switching annual check guidance display on/off.
Starter key at [RUN] position.
(1)
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Press switch 2 to select "Setting" and then
(3)
press switch 5.
Press switch 2 to select "Others" and then
(4)
press switch 5.
Press switch 2 to select "Annual Check
(5)
Guidance Display" and then press switch 5.
(6) Select "On / Off " and press switch 5.
[Setup complete]
(7)
If set ON, indicate the year and month.
(a)
If set ON, then in normal mode, a message
(b)
appears at the set month and year.
RY9212166ELS0086US0
4-S65 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
6. Retrieving entire fail record
Starter key at [RUN] position.
(1)
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Press switch 2 to select "Setting" and then
(3)
press switch 5.
Press switch 2 to select "Others" and then
(4)
press switch 5.
Press switch 2 to select "Retrieve entire fail
(5)
record" and then press switch 5.
Fail record display screen
(6)
Display screen if there is no fail record
(7)
CAUTION
• Not erased even if fail record is deleted.
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[M] Operate AUX2 / Thumb by AUX1 Knob (or Operate AUX1 by AUX2 / Thumb Knob)
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Select "Others" and press switch 5.
(4)
Select "Exchange (AUX1 AUX2/Thumb)"
(5) and press switch 5.
Select "Normal" or "Reverse" and press
(6) switch 5.
[Setup complete]
(7)
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4-S66 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[N] Set Up Changed Condition of Multipurpose Switch
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Setting" and press switch 5.
(3)
Select "Other" and press switch 5.
(4)
Select "Multipurpose mode" and press
switch 5.
(5)
Change the mode number and then press
switch 5.
• Available mode numbers: 00 to 10
(6)
Mode number when shipped: 00
(Multipurpose switch function disabled
and AUX2 hold function disabled)
[Setup complete]
(7)
NOTE
• See "Multipurpose switch function" for details of the multipurpose switch settings.
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4-S67 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Multipurpose Function
Every machines equipped with 2 Service Ports, can activate the "multipurpose switch" function. With this
multipurpose switch function it is possible to use 10 different modes for controlling an additional solenoid valve, or
various other hydraulic functions.
The following instructions will show you how to use this multipurpose function.
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1. How to use the multipurpose function
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Attachment Parts
The following parts must be installed on the machine,
depending on the mode used.
• Additional valve x 1
• Electrical wire harness x1
• Hydraulic hoses
NOTE
• The wire harness connector must be installed on the
additional valve in order to check the voltage with the
multimeter.
• The wire harness of the additional valve is connected to the
"ECU-Main+B (5A)" circuit which is shown on the circuit
diagram in the Workshop Manual. The maximum rated
amperage in the additional valve is 1 amp.
Pin No. Terminal Max rated amperage
<1> + Terminal 1A
<2> - Terminal –
(1) Multipurpose Switch Connector
Yazaki HS025-2PF (7283-2090-30)
or Equivalent
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4-S68 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Handling Procedure
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1. Turn the starter key to the "RUN" position.
Let the engine warm up after start-up for approx. 10 minutes
under no load conditions.
(1) Starter Switch (A) "STOP"
(B) "RUN"
(C) "START"
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2. Lower the pilot control lock lever (UNLOCK).
(1) Pilot Control Lever (A) "Unlock"
(B) "Locked"
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3. Press the AUX port enable switch (switch 3).
NOTE
• The message below is shown when the pilot control lever
is not in the "Unlock" position. Lower the lever to "Unlock",
and then press the AUX port enable switch (switch 3).
(1) AUX Port Enable Switch (Switch 3)
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4-S69 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. Mode number for Multipurpose
Over all there are 10 different modes to use.
Depending on which mode you are selecting, and which valve you installed, you can use the multipurpose switch
to control various other hydraulic functions of your excavator.
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Multipurpose switch
In the model setup, set "Multipurpose switch spec." to "Yes".
Refer to "Model Setup" for the setting procedure.
Several of the following buttons and switches are enabled,
depending on the selected multipurpose switching mode.
NOTE
• The display light (2) comes on when the multipurpose
switching function is operative.
(1) Multipurpose Switch A (A) For America and Canada
(2) Injection Light (B) For Australia
(3) Multipurpose Switch B
(4) Multipurpose Switch C
(AUX2/Thumb One-Way Hold
Switch)
(5) AUX2 Slide Lever
(6) Operating Lever (Left)
(7) Operating Lever (Right)
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4-S70 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Select the number of below table then you can use AUX2 / Thumb
Intended use
AUX2 / Thumb one way hold function with former multipurpose function.
continuous When pressing button "C", AUX2 / Thumb continuous operation is
operation Operation activated. If you press button "C" again, or if you use the AUX2 /
Thumb slider lever, the continuous operation will be deactivated.
Mode number of AUX2 / Thumb continuous operation
Each former multipurpose functions
Mode number 01 ← No multipurpose function
Mode number 03 ← Mode number 02
Mode number 05 ← Mode number 04
Mode number 07 ← Mode number 06
Mode number 09 ← Mode number 08
(1) Button C
(2) AUX2 / Thumb Slider Lever
(A) AUX2 / Thumb
(a) When Pressing Button C
(1)
(X) For UNITED STATES and
Canada
(Y) For Australia
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4-S71 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Purpose Switches swivel - swing operation
Continuous operation of multipupose switch
When button "B" is pressed, the multipurpose switch operates
Mode number 02 continuously. Continuous operation is cancelled by pressing button
How it Works "B" once more. By pressing button "A", the multipurpose switch
becomes enabled. Continuous operation is cancelled by pressing
button "A" once more. The multipurpose switch is enabled by one
button and disabled by another button.
(1) Button A
(2) Button B
(A) Multipurpose Switching
Signal
(a) Press Button B(2) or A(1)
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(1) Multipurpose Sol (HS025-2pf)
(2) Sol Valve (Less than 1.5 A)
(3) Pilot Pressure
(4) Swing
(5) Swivel
(6) Lever
(7) Indicator (Less than 2.0 W)
(a) Less than 18 W
(b) ECU Outlet
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4-S72 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Purpose ON/OFF output (spray attachment, road planer, etc.)
Operation of multipupose switch
Mode number 04 When button "B" is pressed, the multipurpose switch operates.
How it Works When button "B" is released, the operation is cancelled. This
function can also be used by pressing button "A" instead of button
"B".
(1) Button A
(2) Button B
(A) Multipurpose Switching
Signal
(a) Press Button B(2) or A(1)
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(1) Multipurpose Sol (HS025-2pf) (4) Tank (7) AUX2 / Thumb (a) Less than 18 W
(2) Sol Valve (Less than 1.5 A) (5) AUX1 (8) Excavator (b) ECU Outlet
(3) Pilot Pressure (6) ON-OFF Valve (9) Indicator (Less than 3.4 W) (c) Original C/V Section
• (a): 18 W or lower
• (b): ECU output
• (c): Original C/V section for (5), (7) cylinders
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4-S73 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(1) Multipurpose Sol (HS025-2pf)
(2) Relay
(3) Power-Supply (P-Lock-2pf)
(4) Indicator (Less than 2.0 W)
(a) Electrical Outlet
(b) ECU Outlet
(c) Less than 120 W
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Quick Hitch (With AUX1 and AUX2 / Thumb live)
The quick hitch that can be moved by pilot pressure
Intended use
Spring lock mechanism release: single-action, cylinder type:
Mode number 06 double-action (Operates with the blade, swing, etc.)
Multipurpose switch operation
Operation When pressing button "A", the multipurpose switch is operating.
If you release button "A", the operation will be deactivated.
(1) Button A
(A) Multipurpose Signal
(a) When Pressing Button A
(1)
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4-S74 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(1) Multipurpose Switching Solenoid
(2) Solenoid Valve
(3) Pilot Pressure
(4) Swing Section
(5) Single-Acting Quick Hitch
(6) Swing Cylinder
(7) Swing Pedal
(8) Display Light (2.0 W or Lower)
(a) 18 W or Lower
(b) ECU Output
(c) (5) Operates when the Right Swing is
Operated.
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Engcon Tiltrotator mode.
Quick hitch (when also using AUX1 and AUX2/Thumb)
Purpose
Quick hitch operated by hydraulic pilot pressure
Spring lock mechanism release: Single-action
Mode number 08
Operation of multipupose switch
When button "A" and button "B" are pressed, the multipurpose
How it Works
switch operates. When one of the two buttons is released, the
operation is cancelled.
(1) Button A
(2) Button B
(A) Multipurpose Switching
Signal
(a) Press Buttons A(1) and
B(2) Simultaneously
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4-S75 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(1) Multipurpose Sol (HS025-2pf) (5) Rotation (A) Tiltrotator (a) Less than 18 W
(2) Select Valve (6) Bucket or AUX1 or (b) ECU Outlet
(3) Quick Hitch AUX2 / Thumb (c) Allocation of Hydraulic
(4) Tilt (Original C/V Section) Press. Soure
Bucket (Pilot Pressure):
Quick Hitch
AUX1: Tilt
AUX2 / Thumb: Rotation
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4-S76 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Quick Hitch (When using AUX2 / Thumb on the quick designated
port.)
Purpose
Spring lock mechanism release: single-action or double-action,
cylinder type: double-action
Mode number 10
AUX2 / Thumb operation
When pressing button "A", and using the AUX2 / Thumb slide lever
Operation
of the left lever, AUX2 / Thumb can be operated. If button "A" is
released, the operation will be deactivated.
(1) Multipurpose Switch A
(2) AUX2 / Thumb Slide Lever
(A) AUX2 / Thumb
(a) When Pressing
Multipurpose Switch A (1)
and Using the AUX2 /
Thumb Slide Lever (2)
(X) For America and Canada
(Y) For Australia
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(1) AUX2 / Thumb
(2) Double-Action Quick Hitch
(3) Single-Action Quick Hitch
(4) Pilot Pressure
(5) Tank
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4-S77 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[O] At the Time of Replacing the Meters and ECU’s
The message below is shown when the meter and ECU are changed.
1. To check for temporary change for the meter and ECU of another machine
(1) Switch 1, press "No".
(2) Normal screen displayed.
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2. If meter and ECU changed for new parts
Switch 5, press "Yes".
(1)
Press switch 5 "Yes" if the meter has been
changed.
(2) Press switch 1 "No" if the ECU has been
changed.
[Initializes saved settings.]
Pressing switch 4 allows you to check the
items that need to be set up.
(3)
Check the required items, and then turn the
key to [STOP] and make the necessary
settings.
(4)
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4-S78 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[P] Resetting of the Clock after Removing the Battery
If clock is not to be reset
Disconnect the battery, then reconnect the
(1) battery and turn the key to [RUN],
(A)STOP, (B)RUN, (C)START
When "Set Clock" is displayed, press
(2) Switch 1 "No".
Normal screen
(3)
RY9212182ELS0100US0
If clock is to be reset
Disconnect the battery, then reconnect the
(1) battery and turn the key to [RUN],
(A)STOP, (B)RUN, (C)START
When "Set Clock" is displayed, press
(2) Switch 5.
Set the clock and then press switch 5.
(3)
[Setup complete]
(4)
[Clock setting guide]
• Pressing switch 4 ( ) changes the setting item from Yr→ Mo→ Day→ Hr→ Min→ Yr.
• Pressing switch 2 ( ) reduces the number.
• Pressing switch 2 ( ) increases the number.
• Pressing switch 1 while on the clock setting screen takes the screen back without changing the time.
Clock precision: 2 seconds/day
The clock set warning can be switched off if so desired by the user. (Set to display when shipped)
RY9212182ELS0101US0
4-S79 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[5] LIST OF WARNING ALARM DISPLAYS
(1) Warning Display List
When needed, pressing switch 4 displays a detailed description.
Problem or failure Behaviour of machine
Display Lamp Pressing SW4 Message in fail record
(Circumstances) (provisional action)
Fall in oil pressure in
Meter Engine oil Risk of engine seizure :
Red – engine lubrication
pressure error stop engine immediately
system
Cooling water Halt work until the
Red – Meter Over heat temperature above set message disappears.
temperature Keep engine idling.
The machine will
Meter Charging System Failure or charging error
Red – operate until the battery
Error in charging system
dies.
The fuel level indicator
is not displayed on the
Failure in fuel sensor
Red – Meter Fuel Sensor Error meter. Other functions
system
of the machine can be
used.
CANSys (main) Meter CAN Sys (Main) The engine may start
and the machine may
Failure in
Red move. However, the
communications system
machine cannot carry
CANSys (CRS) Meter CAN Sys (CRS)
out any work.
Main Water mixed with Water mixed into the Halt engine and remove
Red –
fuel fuel water from fuel filter.
Machine continues at
low speed rather than
Failure in 2-speed
Red 2-speed SOL Main 2-speed solenoid switching to high speed.
switching system
Other functions can be
used.
AUX1 knob Main AUX1 knob The engine restarts and
the machine moves. But
Main AUX1 right AUX1 Port system AUX1 is not usable. If
Red AUX1 right SOL
solenoid failure other equipment is
functioning, then work
AUX1 left SOL Main AUX1 left solenoid can be continued.
Main AUX2/Thumb
AUX2/Thumb knob The engine restarts and
knob
the machine moves. But
Main AUX2/Thumb right AUX2 Port system AUX2 is not usable. If
Red AUX2/Thumb right SOL
solenoid failure other equipment is
functioning, then work
Main AUX2/Thumb left
AUX2/Thumb left SOL can be continued.
solenoid
4-S80 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Problem or failure Behaviour of machine
Display Lamp Pressing SW4 Message in fail record
(Circumstances) (provisional action)
• Jump start cable
connected to 24V
If connected to 24V
battery or unsuitable
Red Over voltage Main Over voltage battery, stop
device
immediately
• Failure in alternator
Main Angle right The engine restarts and
Angle right solenoid the machine moves. But
solenoid
the angle is not usable.
Red Failure in angle system
If other equipment is
Angle left solenoid Main Angle left solenoid functioning, then work
can be continued.
Engine doesn't return
Failure in accelerator automatically to idling,
Red Accelerator sensor Main Aceelerator sensor
dial but other functions can
be used.
Failure in anti-theft Engine cannot be
Red Antenna Main Antenna
system started
Engine will start, but
Main Lever lock Failure in lever lock
Red Lever lock solenoid machine cannot be
solenoid system
operated
The engine starts and
the machine moves. But
Failure in multipurpose
the multipurpose
switching function (only
Main Multipurpose switching function is not
Red Multipurpose SOL displayed when
solenoid usable. If other
multipurpose switching
equipment is
function is enabled)
functioning, then work
can be continued.
Major system failure.
The engine may start
Sensor or 5V power and the machine may
Red External 5V Main external 5V
shorted move. However, the
machine cannot carry
out any work.
The engine may start
and the machine may
Red 1 to 64 – Failure in engine system move. However, the
machine cannot carry
out any work.
The engine restarts and
Travel pressure Main Travel pressure the machine moves. But
ECO mode is not
Red Failure in EP system usable. If other
equipment is
EP Sol Main EP solenoid
functioning, then work
can be continued.
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4-S81 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(2) Warning Display List
Display Lamp Cause
Fuel low
Yellow
Displayed at 6 minute intervals.
Water temperature rising.
Yellow
Displayed at 6 minute intervals.
Yellow Tried to start engine with an unregistered key
Yellow Tried to start engine with red key
Yellow Periodic check within 10 hours
Yellow Periodic check time has passed
Yellow Periodic check set for this month
Yellow The clock may be set to the wrong time.
– When meter or ECU replaced without doing setup
During setup after changing the meter or the ECU, this screen comes up to confirm the meter has been
–
changed.
4-S82 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Display Lamp Cause
– When neither the meter nor the ECU have been replaced, but some settings need to be made.
– Tried to start the engine with the lever lock still down.
– Switch 3 (AUX) pressed with the lever lock still up.
– Key turned to OFF but not taken out (Anti-theft spec. only)
– Switch 3 (AUX) pressed on a machine without AUX1/AUX2/Thumb spec.
– AI switch pressed on a machine without AI spec.
– Multipurpose switch pressed without being registered.
– Screen for clearing the trip fuel amount
– Communicating with the key
– Displayed for 5 seconds when set to E mode.
– Displayed for 5 seconds when DPF inhibited
4-S83 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Display Lamp Cause
– Displayed for 5 seconds when DPF inhibition cancelled
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(3) Table of DPF Warnings
Display Item Display Item
HP limited to low power Increase engine RPM
Rise in exhaust temperature
Increase engine RPM
Operate carefully
HP limited to low power
Can continue working
DPF clogged up Regeneration prohibited.
Needs maintenance Allow regeneration.
Engine forced to stop
Replace the DPF.
Increase RPM and restart.
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4-S84 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(4) PM Clog Level and the State of the Machine
Inhibit switch ON
Clog Warning Engine
Buzzer Screen Content displayed Status and correction
Level lamp output
Level 0 OFF – – – – –
Level 1 OFF – – – – –
Regeneration of DPF is
Blinking ··PiPiPi··
Level 2 – inhibited. –
(Yellow) (Continue)
Allow regeneration.
··PiPiPi··
Regeneration of DPF is
(0 to 50 sec.)
inhibited.
50 % *2
Allow regeneration.
Pi-···Pi-
HP limited to low power.
(50 to 60 sec.)
Blinking
Level 3
(Red)
Engine forced to stop Turn and maximize the accelerator
Pi-···Pi-
– Increase RPM and dial and restart
(from 60 sec.)
restart *1
PiPiPiPi
Use the engine diagnosis tool and
(0 to 50 sec.)
Blinking DPF clogged up regenerate it manually
Level 4 50 %
(Red) Needs maintenance *1
Pi-···Pi-
*2
(from 50 sec.)
Blinking PiPiPiPi
Level 5 50 % Replace the DPF DPF is clogged. Needs replacement.
(Red) (Continue)
The engine rpm drops up to only 2000 rpm while pressing the AI switch.
PM clog level does not change when the key is turned OFF. The level stays the same when the engine restarts.
*1 : If the lever lock is up, the engine stops forcibly in 60 seconds.
*2 : If the lever lock is down, the engine does not stop. The same buzzer from 0 to 50 sec. keeps sounding.
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4-S85 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Inhibit switch OFF
Clog Warning Engine Contents
Buzzer Engine RPM Screen Status and correction
Level lamp output displayed
Level 0 OFF – – – – – –
Exhaust More than 2000 engine
temperature RPM: DPF regenerates
··PiPiPi··
Blinking rising Less than 2000 engine RPM:
Level 1 (Every – –
(Yellow) Operate carefully DPF may not
60 sec.)
Can continue auto-regenerate due to open
working air and water temp.
Exhaust
temperature
More than rising
Being auto-regenerated
2000 rpm Operate carefully
Can continue
working
Exhaust
temperature
··PiPiPi··
Blinking rising
Level 2 (Every –
(Yellow) Operate carefully • When the engine RPM is
60 sec.)
Can continue low, DPF may not
Less than working auto-regenerate due to
2000 rpm open air and water temp.
• The screen changes
Increase engine every 3 sec.
RPM
Exhaust
temperature
rising
Operate carefully
Can continue
PiPiPi working • Being auto-regenerated
Blinking More than
(Every 50 % • The screen is changed
(Yellow) 2000 rpm
60 sec.) every 3 sec.
HP limited to low
power
Exhaust
temperature
rising
Level 3 • When the engine RPM is
Operate carefully
··PiPiPi·· Can continue low, DPF may not
(0-50 sec.) working auto-regenerate due to
50 % open air and water temp.
Pi-···Pi- • The screen changes
(50-60 sec.) Increase engine every 3 sec.
Blinking Less than RPM *2
(Red) 2000 rpm HP limited low
power
Engine forced to
Turn and maximize the
Pi-···Pi- stop
– accelerator dial and restart.
(from 60 sec.) Increase RPM
*1
and restart
PiPiPiPi Use the engine diagnosis
(0-50 sec.) DPF clogged up tool and regenerate it
Blinking
Level 4 50 % – Needs manually
(Red)
Pi-···Pi- maintenance *1
(from 50 sec.) *2
4-S86 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
Clog Warning Engine Contents
Buzzer Engine RPM Screen Status and correction
Level lamp output displayed
Blinking PiPiPiPi DPF is clogged. Needs
Level 5 50 % – Replace the DPF
(Red) (Continue) replacement.
The engine rpm drops up to only 2000 rpm while pressing the AI switch.
PM clog level does not change when the key is turned OFF. The level stays the same when the engine restarts.
*1 : If the lever lock is up, the engine stops forcibly in 60 seconds.
*2 : If the lever lock is down, the engine does not stop. The same buzzer from 0 to 50 sec. keeps sounding.
RY9212166ELS0206US0
4-S87 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(5) Table of Engine System Error Numbers
Always happens
Symptom when error occurs
May happen
Engine performance
No. Dis-
Error location Limited Limited Notes
played Won't start
RPM HP
1 RPM sensor system
2 Fuel/rail pressure system Fuel may run out.
3 SCV system error
4 Intake temperature sensor system
5 Water temperature sensor system
6 Fuel temperature sensor system
7 Injector system
8 Intake pressure sensor system
9 Battery voltage related
10 Sensor voltage related
11 Main relay related
12 Atmospheric pressure sensor related
13 EGR valve related
14 EGR starting to close warning
15 Emissions warning
16 Air heater related
17 Engine ECU
18 Communication error
19 Mass airflow sensor related
20 Intake throttle
21 Pressure differential sensor related
22 Exhaust temperature sensor (DOC intake)
23 Exhaust temperature sensor (DOC outlet)
24 Exhaust temperature sensor (DPF outlet)
25 Simultaneous break in all exhaust temperature sensors
26 DOC reaction
27 DPF regeneration time up
28 Insufficient DPF regeneration water temperature rise
29 Regeneration too frequent
30 Engine fuel system (P/L)
31 Engine fuel system (rail pressure)
32 Engine fuel system (fuel leak)
33 Engine fuel system (SCV)
34 Engine fuel system (Supply pump)
35 Engine air intake system (Insufficient intake)
36 Engine air intake system (Insufficient boost pressure)
37 Engine exhaust temperature (DOC inlet temperature error)
38 Engine exhaust temperature (DPF inlet temperature error)
39 Engine exhaust temperature (DPF outlet temperature error)
40 Starter relay start warning
60 Other errors
RY9212148ELS0069US0
4-S88 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
6. TROUBLESHOOTING (METER PANEL EDITION)
[1] MACHINE RELATED SYSTEM
(1) Engine Oil Pressure Errors
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
2. Check whether the oil lamp (b) is lit in red or off.
(1) Engine Oil (a) Warning Lamp
Press Err (b) Oil Lamp
Stop Engine
RY9212032ELS0008US0
[Test Conditions]
1. Key switch : ON
(a) If the oil lamp is lit : caused by a short
(b) If the oil lamp is off : caused by break in wiring
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
RY9212166ELS0089US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
4-S89 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
3. Tester mode
1. Select the tester mode.
2. Check the operation of the oil switch according to the table
below.
Regu- Oil When Oil When Oil
lar Lamp cut off Lamp shorted Lamp
Key Off Off Off Off
Key On Lit Off Lit
Key Start Off Off Lit
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
(1) Engine Speed
Battery V
Oil SW
Charging
Starter
RY9212032ELS0002US0
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Checking fuses is not necessary.
RY9212001ELS0008US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
3. Causes when a break in wiring
[Test Conditions]
1. Key switch : OFF
2. The oil switch connector is disconnected.
3. There is a break somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (pull with a max of 3 kgf (30 N, 7 lbf) of force) If it
comes off, plug the connector back in securely and check the
operation of the oil switch again in the tester mode.
Criteria
Regular : no break
Irregular : has a break
RY9212166ELS0090US0
4. Causes when a short
[Test Conditions]
1. Key switch : OFF
2. The oil switch wire is pinched against or touching the body.
If the insulation is damaged, repair it properly and check the
operation of the oil switch again in the tester mode.
Criteria
Regular : no short
Irregular : shorted
RY9212166ELS0091US0
4-S90 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[C] Testing with a Circuit Tester
1. Voltage check
[Measurement Conditions]
1. Disconnect the oil switch connector.
2. Key switch : ON
3. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) Oil switch connector <1> Body GND –
Regular : 12 V
Irregular : Large discrepancy from 12 V
RY9212166ELS0092US0
2. Continuity check
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect meter connector.
3. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) Meter connector <9> Oil switch connector <1>
Regular : Continuity
Irregular : No continuity
RY9212166ELS0093US0
[D] Testing the Equipment Itself
1. Measuring engine pressure
[Measurement Conditions]
1. Remove the oil switch, attach a pressure gauge and measure
the pressure.
49 KPa
When Usable
0.5 kgf/cm2
Idling Limit
7 psi
Factory 200 to 390 KPa
Engine Oil Pressure specifica- 2.0 to 4.0 kgf/cm2
At Rated tion 29 to 56 psi
RPM 150 KPa
Usable
1.50 kgf/cm2
Limit
21 psi
15 to 19 N-m
Oil switch tapering screw
Tightening torque 1.5 to 2.0 kgf·m
R1/8
11 to 14 lbf·ft
Criteria
Regular : Within factory specification
Irregular : Outside factory specification
RY9212166ELS0094US0
2. Settings after replacing device
1. No settings required.
RY9212001ELS0013US0
4-S91 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
3. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0003US0
(2) Charging System Errors
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
2. Check whether the charging lamp (b) is lit in red or off.
(1) Charging (a) Warning Lamp
Sys Err (b) Charging Lamp
RY9212032ELS0009US0
[Test Conditions]
1. Key switch : ON
(a) If the charging lamp is lit : caused by a short
(b) If the charging lamp is off : caused by break in wiring
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
RY9212166ELS0095US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
4-S92 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
3. Tester mode
1. Select the tester mode.
2. Check the operation of the charging lamp according to the table
below.
Charg- Charg- Charg-
Regu- When When
ing ing ing
lar cut off shorted
Lamp Lamp Lamp
Key Off Off Off Off
Key On Lit Off Lit
Key Start Off Off Lit
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
(1) Engine Speed
Battery V
Oil SW
Charging
Starter
RY9212166ELS0163US0
[B] Inspecting each Device Visually and Physically
1. Checking fuses
Check whether the alternator fuse (10A) is blown.
RY9212166ELS0096US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
3. Causes when a break in wiring
[Test Conditions]
1. Key switch : OFF
2. The alternator connector is disconnected.
3. There is a break somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (pull with a max of 3 kgf (30 N, 7 lbf) of force) If it
comes off, plug the connector back in securely and check the
operation of the charging switch again in the tester mode.
Criteria
Regular : no break
Irregular : has a break
RY9212166ELS0097US0
4-S93 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
4. Causes when a short
[Test Conditions]
1. Key switch : OFF
2. The alternator connector wire is pinched against or touching the
body.
If the insulation is damaged, repair it properly and check the
operation of the charging switch again in the tester mode.
Criteria
Regular : no short
Irregular : shorted
RY9212166ELS0098US0
[C] Testing with a Circuit Tester
1. Voltage check
[Measurement Conditions]
1. Disconnect alternator connector.
2. Key switch : ON
3. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) Alternator connector <1> Body GND –
(b) Alternator connector <2> Body GND –
Regular : 12 V
Irregular : Large discrepancy from 12 V
RY9212166ELS0099US0
2. Continuity check
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect meter connector.
3. Remove the 10A fuse.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) Meter connector <10> Alternator connector <2>
(b) 10A fuse – Meter connector <1>
Regular : Continuity
Irregular : No continuity
RY9212166ELS0100US0
4-S94 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[D] Testing the Equipment Itself
1. Inspecting the alternator
1. Check for a cut, loose or slipping fan belt.
2. Measure the voltage between terminal B of the alternator and
body GND. If the measured voltage is about 12V, it is normal. If
the measured voltage is low, it may indicate insufficient battery
capacity or looseness in connections somewhere before the
alternator.
3. Next, start the engine and measure the voltage generated when
the alternator is operating. Take the measurement between
terminal B on the alternator side and the body GND. If the
measured voltage is about 14V, it is normal. If the measured
voltage does not vary from the battery voltage (about 12V), then
the alternator itself or the regulator is faulty.
Criteria
Regular : Within factory specification
Irregular : Outside factory specification
(A) Displacement 7 to 9 mm
(0.3 to 0.4 in.)
RY9212166ELS0101US0
2. Settings after replacing device
1. No settings required.
RY9212001ELS0013US0
3. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0003US0
(3) Fuel Sensor Errors
[A] Checking the Meter Panel
1. Information displayed on the meter panel
Check whether or not the warning lamp (a) on the panel is
blinking red or not.
(1) Fuel Sensor (a) Warning Lamp
Err
RY9212032ELS0010US0
4-S95 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[Test Conditions]
1. Key switch : ON
(a) If the fuel level is at the top : caused by a short
(b) If the fuel level is blank : caused by a break
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
RY9212166ELS0102US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
3. Tester mode
1. Select the tester mode.
2. Start the engine.
3. Check the display for the voltage and resistance of the fuel
based on the following table.
Fuel voltage Resistance
Regular (reference value) 2.3 V 92Ω
When cut off 5.00 V 260Ω
When shorted 0.00 V 0Ω
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
(1) Water Temp.
Fuel
Refueling SW
RY9212166ELS0103US0
4-S96 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Checking fuses is not necessary.
RY9212001ELS0008US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
3. Causes when a break in wiring
[Test Conditions]
1. Key switch : OFF
2. Fuel sensor connector disconnected.
3. There is a break somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (pull with a max of 3 kgf (30 N, 7 lbf) of force) If it
comes off, plug the connector back in securely and check the
voltage and resistance for the fuel again in the tester mode.
Criteria
Regular : no break
Irregular : has a break
RY9212166ELS0104US0
4. Causes when a short
[Test Conditions]
1. Key switch : OFF
2. The fuel sensor wire is pinched against or touching the body.
If the insulation is damaged, repair it properly and check the
voltage and resistance for the fuel again in the tester mode.
Criteria
Regular : no short
Irregular : shorted
RY9212166ELS0105US0
[C] Testing with a Circuit Tester
1. Voltage check
[Measurement Conditions]
1. Disconnect the fuel sensor connector.
2. Key switch : ON
3. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Fuel sensor Fuel sensor
(a) <1> <2>
connector connector
Fuel sensor
(b) <1> Body GND –
connector
Regular : 12 V
Irregular : Large discrepancy from 12 V
RY9212166ELS0106US0
4-S97 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. Continuity check
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect meter connector.
3. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Fuel sensor
(a) <1> Meter connector <1>
connector
Fuel sensor
(b) Meter connector <14> <2>
connector
Regular : Continuity
Irregular : No continuity
RY9212166ELS0107US0
[D] Testing the Equipment Itself
1. Inspecting the fuel sensor
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the connector from the fuel sensor and take
measurements.
3. Refer to the following table for the resistance at different float
positions.
Factory specification
Float position F (a) 1/2 (b) E (c)
Resistance value (Ω) 3 ±1 32.5 110 ±2.5
Criteria
Regular : Within factory specification
Irregular : Outside factory specification
(a) Full (c) Empty
(b) Half
RY9212166ELS0108US0
2. Settings after replacing device
1. No settings required.
RY9212001ELS0013US0
3. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0003US0
4-S98 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(4) Water Mixed into Fuel
Empty the fuel filter and the water separator drain and then check the warning lamp.
If the water has been removed adequately, but a warning still appears, then the sensor is probably defective.
RY9212166ELS0170US0
(1) Fuel Filter (3) Drain Cock
(2) Bolt
RY9212166ELS0171US0
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
(1) Water got mixed (a) Warning Lamp
with fuel
RY9212166ELS0172US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
3. Tester mode
1. Tester mode checking is not necessary.
RY9212166ELS0173US0
4-S99 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Checking fuses is not necessary.
RY9212001ELS0008US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
3. Causes of wiring disconnection
1. Key switch: OFF
2. Water level switch connector is detached.
3. There is a disconnection somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (Pulling force not to exceed 3kgf)
If connector becomes detached, re-install the connector
securely.
RY9212166ELS0174US0
4. Causes of shorting
[Test Conditions]
1. Key switch: OFF
2. The water level switch connector wire is pinched against the
body or touching the body.
If the insulation is damaged, repair carefully.
RY9212166ELS0175US0
4-S100 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[C] Testing with a Circuit Tester
1. Voltage check
[Measurement Conditions]
1. Disconnect the water level switch connector.
2. Key switch: ON
3. Check the voltage of the harness side connectors based on the
table below.
Meas
urem Connector name Pin No. Connector name Pin No.
ent
(a) Water level switch <1> Water level switch <2>
(b) Water level switch <2> Body GND –
Regular: 12V
Irregular: Large deviation from 12V
RY9212166ELS0176US0
2. Continuity check
[Measurement Conditions]
1. Disconnect the water level switch connector from the fuel filter.
2. Measure the resistance between the connector (2P) terminals
on the filter side.
Regular: No continuity
Irregular: Continuity
(a) Water Level Switch
RY9212166ELS0177US0
(5) Engine System Errors
1. Information displayed on the meter panel
1. Check whether or not the warning lamp on the panel is blinking
red.
2. Press the info button (b) and check the additional content.
Example) 1
• See next page for details of the additional content.
(1) Engine Sys Err (a) Warning Lamp
(b) Info Button
RY9212166ELS0178US0
[2] FRONT-END SYSTEMS
(1) Lever Lock System Errors
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
2. Press the info button (b) and check the additional content.
Ex.) Lever lock SOL
(1) Lever Lock (a) Warning Lamp
Sys Err (b) Info Button
RY9212032ELS0014US0
4-S101 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
3. Tester mode
1. Select the tester mode.
2. Start the engine.
3. Put the machinery operation lever lock in the [Unlock] position.
4. Operate the lever lock switch and lever lock solenoid and check
the switch according to the following table.
Warn- Warn- When Warn-
Regu- When
ing ing shorte ing
lar cut off
lamp lamp d lamp
Lever lock
Off Off Off
switch ON
Lever lock
Off Off Off
switch OFF
Lever lock
Off Off Off
solenoid ON
Lever lock
Off Off Off
solenoid OFF
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
(1) 2 Speed SW (c) Unlock
2 Speed SOL (d) Lock
Lever Lock SW (e) Machinery Operation Lever Lock
Lever Lock SOL
Air Cleaner
RY9212166ELS0201US0
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Check whether the 5A lever lock fuse is blown.
RY9212166ELS0109US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
4-S102 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
3. Causes when a break in wiring
[Test Conditions]
1. Key switch : OFF
2. The lever lock switch connector is disconnected.
3. The lever lock solenoid connector is disconnected.
4. There is a break somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (pull with a max of 3 kgf (30 N, 7 lbf) of force) If it
comes off, plug the connector back in securely and check the lever
lock switch and lever lock solenoid in the tester mode.
Criteria
Regular : no break
Irregular : has a break
(a) Lever Lock Solenoid Connector (b) Lever Lock Switch Connector
RY9212166ELS0110US0
4. Causes when a short
[Test Conditions]
1. Key switch : OFF
2. The lever lock switch connector wire and/or lever lock solenoid
connector are pinched against or touching the body.
If the insulation is damaged, repair it properly and check the
lever lock switch and the lever lock solenoid again in the tester
mode.
Criteria
Regular : no short
Irregular : shorted
(a) Lever Lock Switch Connector
RY9212166ELS0111US0
[C] Testing with a Circuit Tester
1. Voltage check (lever lock switch)
[Measurement Conditions]
1. Disconnect the lever lock switch connector.
2. Key switch : ON
3. Put the machinery operation lever lock in the [Unlock] position.
4. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Lever lock switch Lever lock switch
(a) <2> <1>
connector connector
Lever lock switch
(b) <2> Body GND –
connector
Regular : 12 V
Irregular : Large discrepancy from 12 V
RY9212166ELS0112US0
4-S103 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. Continuity check (lever lock switch)
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect lever lock switch connector and lever lock solenoid
connector.
3. Put the machinery operation lever lock in the [Unlock] position.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Lever lock switch
(a) Lever lock fuse – <2>
connector
Lever lock switch Lever lock solenoid
(b) <2> <1>
connector connector
Regular : Continuity
Irregular : No continuity
RY9212166ELS0113US0
3. Voltage check (lever lock solenoid)
[Measurement Conditions]
1. Disconnect lever lock solenoid connector.
2. Key switch : ON
3. Put the machinery operation lever lock in the [Unlock] position.
4. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Lever lock solenoid Lever lock solenoid
(a) <1> <2>
connector connector
Lever lock solenoid
(b) <1> Body GND –
connector
Regular : 12 V
Irregular : Large discrepancy from 12 V
RY9212166ELS0114US0
4-S104 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
4. Continuity check (lever lock solenoid)
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the ECU connector.
3. Disconnect lever lock solenoid connector.
4. Put the machinery operation lever lock in the [Unlock] position.
5. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Lever lock solenoid
(a) <1> ECU connector <67>
connector
Lever lock solenoid
(b) <2> ECU connector <62>
connector
Regular : Continuity
Irregular : No continuity
RY9212166ELS0115US0
4-S105 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[D] Testing the Equipment Itself
1. Inspecting the lever lock switch
[Test Conditions]
1. Key switch : OFF
2. Disconnect the lever lock switch connector from the machine,
press the switch and measure it separately.
Criteria
Regular : no break
Irregular : has a break
(a) Lever Lock Switch (c) Lever Lock Switch Connector
(b) Lever Lock Switch Connector Terminals
RY9212166ELS0116US0
2. Testing the lever lock solenoid
[Test Conditions]
1. Key switch : OFF
2. Disconnect lever lock solenoid connector from the machine and
test the solenoid separately.
Lever lock solenoid Factory specification 12 Ω ±10 %
Criteria
Regular : no break
Irregular : has a break
(a) Lever Lock Solenoid Terminals
RY9212166ELS0117US0
3. Settings after replacing device
1. No settings required.
RY9212001ELS0020US0
4. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0004US0
4-S106 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(2) Travel 2-Speed System Error
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
2. Press the info button (b) and check the additional content.
Ex.) 2-speed solenoid
(1) Travel2 Speed Sys Err (a) Warning Lamp
(b) Info Button
RY9212032ELS0016US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
3. Tester mode
1. Select the tester mode.
2. Start the engine.
3. Put the machinery operation lever lock in the [Unlock] position
and press the 2-speed switch.
4. Operate the 2-speed switch and check the 2-speed switch and
2-speed solenoid based on the following table.
2- 2- When 2-
Regu- When
speed speed shorte speed
lar cut off
lamp lamp d lamp
2-speed switch
Lit Lit Off
ON
2-speed switch
Off Off Off
OFF
2-speed
Lit Lit Off
solenoid ON
2-speed
Off Off Off
solenoid OFF
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
(1) 2 Speed SW (a) 2-Speed Switch
2 Speed SOL
Lever Lock SW
Lever Lock SOL
Air Cleaner
RY9212166ELS0202US0
4-S107 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Checking fuses is not necessary.
RY9212001ELS0008US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
3. Causes when a break in wiring
[Test Conditions]
1. Key switch : OFF
2. The 2-speed solenoid connector disconnected.
3. The 2-speed switch connector disconnected.
4. There is a break somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (pull with a max of 3 kgf (30 N, 7 lbf) of force) If it
comes off, plug the connector back in securely and check the
2-speed solenoid and the 2-speed switch in the tester mode.
Criteria
Regular : no break
Irregular : has a break
(a) 2-Speed Solenoid Connector (b) 2-Speed Switch Connector
RY9212166ELS0164US0
4. Causes when a short
[Test Conditions]
1. Key switch : OFF
2. The wiring of the 2-speed solenoid connector and/or the
2-speed switch connector are pinched against or touching the
body
If the insulation is damaged, repair it properly and check the
2-speed solenoid and the 2-speed switch again in the tester
mode.
Criteria
Regular : no short
Irregular : shorted
(a) 2-Speed Solenoid Connector (b) 2-Speed Switch Connector
RY9212166ELS0165US0
4-S108 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[C] Testing with a Circuit Tester
1. Voltage check (2-speed solenoid)
[Measurement Conditions]
1. Disconnect the travel 2-speed solenoid connector.
2. Key switch : ON
3. Put the machinery operation lever lock in the [Unlock] position
and press the 2-speed switch.
4. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
2-speed solenoid 2-speed solenoid
(a) <1> <2>
connector connector
2-speed solenoid
(b) <1> Body GND –
connector
Regular : 12 V
Irregular : Large discrepancy from 12 V
RY9212166ELS0118US0
2. Continuity check (2-speed solenoid)
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the travel 2-speed solenoid connector.
3. Disconnect the ECU connector.
4. Put the machinery operation lever lock in the [Unlock] position
and press the 2-speed switch.
5. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
2-speed solenoid
(a) <1> ECU connector <81>
connector
Regular : Continuity
Irregular : No continuity
RY9212166ELS0119US0
3. Voltage check (2-speed switch)
[Measurement Conditions]
1. Disconnect the angle grip SW connector.
2. Key switch : ON
3. Put the machinery operation lever lock in the [Unlock] position
and press the 2-speed switch.
4. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Angle grip SW Angle grip SW
(a) <1> <2>
connector connector
Angle grip SW
(b) <1> Body GND –
connector
Regular : 12 V
Irregular : Large discrepancy from 12 V
RY9212166ELS0166US0
4-S109 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
4. Continuity check (2-speed switch)
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the ECU connector.
3. Put the machinery operation lever lock in the [Unlock] position
and press the 2-speed switch.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Angle grip SW
(a) <2> ECU connector <57>
connector
Angle grip SW
(b) <1> ECU connector <41>
connector
Regular : Continuity
Irregular : No continuity
RY9212166ELS0167US0
[D] Testing the Equipment Itself
1. Testing the 2-speed switch
[Test Conditions]
1. Key switch : OFF
2. Disconnect the angle grip SW connector from the machine,
press the switch and measure it separately.
Criteria
Regular : no break
Irregular : has a break
(a) 2-Speed Switch
RY9212166ELS0168US0
2. Testing the 2-speed solenoid
[Test Conditions]
1. Key switch : OFF
2. Disconnect 2-speed solenoid connector from the machine and
test the solenoid separately.
2-speed solenoid Factory specification 12 Ω ±10 %
Criteria
Regular : Within factory specification
Irregular : Outside factory specification
(a) 2-Speed Solenoid Terminals
RY9212166ELS0120US0
3. Settings after replacing device
1. Select the AI setting.
Criteria
Regular : setting complete
Irregular : setting failed
(1) AI Set
AUX Set
AUX2/Thumb Set
RY9212032ELS0018US0
4-S110 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
4. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0004US0
4-S111 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[3] AUTO IDLING (AI) SYSTEM
(1) Accelerator Sensor Errors
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
2. Press the info button (b) and check the additional content.
Ex.) Accelerator sensor
(1) AI Sys Err (a) Warning Lamp
(b) Info Button
RY9212032ELS0007US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
3. Tester mode
1. Select the tester mode.
2. Start the engine.
3. Turn the accelerator dial to the right (hi-speed) and to the left
(lo-speed) and check the accelerator POT voltage based on the
following table.
Design Accelerator When
Regular When cut off
Value POT shorted
Idling 1.68 ± 0.2 V 0.05 V Voltage fails to
MAX 3.39 ± 0.28 V 0.05 V stabilize
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
(1) Accel POT (b) Slow
Governor POT (c) Fast
Motor Current
RY9212032ELS0020US0
4-S112 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Checking fuses is not necessary.
RY9212001ELS0008US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
3. Causes when a break in wiring
[Test Conditions]
1. Key switch : OFF
2. AI console connector disconnected.
3. There is a break somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (pull with a max of 3 kgf (30 N, 7 lbf) of force) If it
comes off, plug the connector back in securely, turn the accelerator
dial to the right (hi-speed) and the left (lo-speed) and check the
voltage of the accelerator sensor again in the tester mode.
Criteria
Regular : no short
Irregular : shorted
RY9212166ELS0121US0
4. Causes when a short
[Test Conditions]
1. Key switch : OFF
2. The wiring of the AI console connector is pinched against or
touching the body.
If the insulation is damaged, repair it properly, turn the
accelerator dial to the right (hi-speed) and the left (lo-speed)
and check the voltage of the accelerator sensor again in the
tester mode.
Criteria
Regular : no short
Irregular : shorted
RY9212166ELS0122US0
4-S113 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[C] Testing with a Circuit Tester
1. Voltage check
[Measurement Conditions]
1. Disconnect the AI console connector.
2. Key switch : ON
3. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) AI console connector <8> AI console connector <4>
(b) AI console connector <8> Body GND –
Regular : 5 V
Irregular : Large discrepancy from 5 V
RY9212166ELS0123US0
2. Continuity check
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the AI console connector.
3. Disconnect the ECU connector.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) AI console connector <7> ECU connector <7>
(b) AI console connector <8> ECU connector <11>
(c) AI console connector <4> ECU connector <10>
Regular : Continuity
Irregular : No continuity
RY9212166ELS0124US0
4-S114 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[D] Testing the Equipment Itself
1. Testing the accelerator sensor
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the accelerator sensor from the machine and test it
separately.
Factory specification Min. Max.
Accelerator sensor 4 to 8 1 kΩ ± 10 % 1 kΩ ± 10 %
Accelerator sensor 3 to 4 720 Ω 380 Ω
Accelerator sensor 3 to 8 380 Ω 720 Ω
Criteria
Regular : Within factory specification
Irregular : Outside factory specification
(a) Accelerator Dial Terminal
Numbers
RY9212166ELS0125US0
2. Settings after replacing device
1. Select the AI setting.
Criteria
Regular : setting complete
Irregular : setting failed
(1) AI Set
AUX Set
AUX2/Thumb Set
RY9212032ELS0005US0
3. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0003US0
4-S115 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(2) Testing the AI Pressure Switch
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. When the auto-idle switch (a) on the panel is pressed, check
whether the auto-idle lamp (b) lights or is off.
Criteria
Regular : lamp lights
Irregular : lamp off
(a) Auto-Idle Switch (b) Auto-Idle Lamp
RY9212166ELS0126US0
2. Reading the failure history
1. Checking the failure history is not required.
RY9212001ELS0048US0
3. Tester mode
1. Select the tester mode.
2. Start the engine.
3. Check the operation of the auto-idle switch according to the
table below.
Regular When cut off When shorted
Operating
Not
operating
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
(1) AI Press SW
AI operation SW
Compressor
Water Temp.
Motor Current
RY9212032ELS0023US0
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Checking fuses is not necessary.
RY9212001ELS0008US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
4-S116 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
3. Causes when a break in wiring
[Test Conditions]
1. Key switch : OFF
2. The auto-idle pressure switch connector is disconnected.
3. There is a break somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (pull with a max of 3 kgf (30 N, 7 lbf) of force) If it
comes off, plug the connector back in securely and check the
operation of the auto-idle switch again in the tester mode.
Criteria
Regular : no break
Irregular : has a break
RY9212166ELS0127US0
4. Causes when a short
[Test Conditions]
1. Key switch : OFF
2. The wire of the auto-idle pressure switch connector is pinched
against or touching the body.
If the insulation is damaged, repair it properly and check the
operation of the auto-idle switch again in the tester mode.
Criteria
Regular : no short
Irregular : shorted
RY9212166ELS0128US0
[C] Testing with a Circuit Tester
1. Voltage check
[Measurement Conditions]
1. Disconnect the auto-idle pressure switch connector.
2. Key switch : ON
3. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Auto-idle pressure Auto-idle pressure
(a) <1> <2>
switch connector switch connector
Auto-idle pressure
(b) <1> Body GND –
switch connector
Regular : 12 V
Irregular : Large discrepancy from 12 V
RY9212166ELS0129US0
4-S117 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. Continuity check
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the auto-idle pressure switch connector.
3. Disconnect the ECU connector.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Auto-idle pressure
(a) <1> ECU connector <76>
switch connector
Auto-idle pressure
(b) <2> ECU connector <50>
switch connector
Regular : Continuity
Irregular : No continuity
RY9212166ELS0130US0
[D] Testing the Equipment Itself
1. Measuring the auto-idle pressure
[Measurement Conditions]
1. Remove the auto-idle pressure switch from the control valve
and attach a pressure gauge and test the pressure.
Operating AI pressure
Engine RPM
pressure switch
25 ± 3 kgf/cm2
2.5 ± 0.3 MPa OFF Accelerate from idling rpm to max rpm.
360 ± 45 psi
20 ± 3 kgf/cm2
2.0 ± 0.3 MPa ON Decelerate from max rpm to idling rpm.
280 ± 45 psi
The AI switch is normally closed (normally ON)
Criteria
Regular : Within factory specification
Irregular : Outside factory specification
(a) Pressure (b) State of Pressure Switch
RY9212166ELS0131US0
2. Settings after replacing device
1. Select the AI setting.
Criteria
Regular : setting complete
Irregular : setting failed
(1) AI Set
AUX Set
AUX2/Thumb Set
RY9212032ELS0005US0
4-S118 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
3. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0003US0
4-S119 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(3) Testing the AI Switch
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. When the auto-idle switch (a) on the panel is pressed, check
whether the auto-idle lamp (b) lights or is off.
Criteria
Regular : lamp lights
Irregular : lamp off
(a) Auto-Idle Switch (b) Auto-Idle Lamp
RY9212166ELS0132US0
2. Reading the failure history
1. Checking the failure history is not required.
RY9212001ELS0048US0
3. Tester mode
1. Select the tester mode.
2. Check the operation of the auto-idle switch according to the
table below.
Regular When cut off When shorted
With AI SW
pressed
With AI SW
released
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
(1) AI Press SW
AI operation SW
Compressor
Water Temp.
Motor Current
RY9212166ELS0169US0
4-S120 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Checking fuses is not necessary.
RY9212001ELS0008US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
3. Causes when a break in wiring
[Test Conditions]
1. Key switch : OFF
2. Auto-idle console connector disconnected.
3. There is a break somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (pull with a max of 3 kgf (30 N, 7 lbf) of force) If it
comes off, plug the connector back in securely and check the
operation of the auto-idle switch again in the tester mode.
Criteria
Regular : no break
Irregular : has a break
RY9212166ELS0133US0
4. Causes when a short
[Test Conditions]
1. Key switch : OFF
2. The wiring of the auto-idle console connector is pinched against
or touching the body.
If the insulation is damaged, repair it properly and check the
operation of the auto-idle switch again in the tester mode.
Criteria
Regular : no short
Irregular : shorted
RY9212166ELS0134US0
[C] Testing with a Circuit Tester
1. Voltage check
[Measurement Conditions]
1. Disconnect auto-idle console connector.
2. Key switch : ON
3. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Auto-idle console Auto-idle console
(a) <2> <6>
connector connector
Auto-idle console
(b) <2> Body GND –
connector
Regular : 12 V
Irregular : Large discrepancy from 12 V
RY9212166ELS0135US0
4-S121 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. Continuity check
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect auto-idle console connector.
3. Disconnect the ECU connector.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Auto-idle console
(a) <6> ECU connector <75>
connector
Auto-idle console
(b) <2> ECU connector <76>
connector
Regular : Continuity
Irregular : No continuity
RY9212166ELS0136US0
[D] Testing the Equipment Itself
1. Testing the accelerator dial
[Measurement Conditions]
1. Key switch : OFF
2. Remove the accelerator dial from the machine and replace with
a new accelerator dial.
3. Select the tester mode and check the voltage of the accelerator
dial.
Criteria
Regular : Within factory specification
Irregular : Outside factory specification
RY9212166ELS0137US0
2. Settings after replacing device
1. Select the AI setting.
Criteria
Regular : setting complete
Irregular : setting failed
(1) AI Set
AUX Set
AUX2/Thumb Set
RY9212032ELS0005US0
4-S122 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
3. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0003US0
4-S123 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[4] ANTI-THEFT (AT) SYSTEM
(1) Anti-Theft System Errors
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
2. Press the info button (b) and check the additional content.
Ex.) Antenna
(1) Ant-theft (a) Warning Lamp
Sys Err (b) Info Button
RY9212032ELS0025US0
[Test Conditions]
1. Key switch : OFF
2. Check whether the anti-theft indicator is blinking or not.
(a) Anti-Theft Indicator
RY9212001ELS0198US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
3. Tester mode
1. Select the tester mode.
2. Check the anti-theft antenna.
Regular Irregular
Anti-theft antenna ×
On/off Valid cancel ×
Red key Black key – – –
(1) AT Anten
AT Mode
Key : Red Black
Key : Yellow Green
Tag : Yellow Green
RY9212032ELS0026US0
4-S124 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Checking fuses is not necessary.
RY9212001ELS0008US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
3. Causes when a break in wiring
[Measurement Conditions]
1. Key switch : OFF
2. Anti-theft connector disconnected.
3. There is a break somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (pull with a max of 3 kgf (30 N, 7 lbf) of force) If it
comes off, plug the connector back in securely and check the
anti-theft antenna again in the tester mode.
Criteria
Regular : no break
Irregular : has a break
RY9212166ELS0138US0
4. Causes when a short
[Measurement Conditions]
1. Key switch : OFF
2. The anti-theft connector wire is pinched against or touching the
body.
If the insulation is damaged, repair it properly and check the
operation of the anti-theft antenna again in the tester mode.
Criteria
Regular : no short
Irregular : shorted
(a) Anti-Theft Connector
RY9212166ELS0139US0
4-S125 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[C] Testing with a Circuit Tester
1. Voltage check
[Measurement Conditions]
1. Disconnect the anti-theft connector.
2. Key switch : ON
3. Measure the voltage based on the table below.
Mea-
sure- Connector Name (+ terminal side) Pin No. Connector Name (- terminal side) Pin No.
ment
(a) Anti-theft connector <5> Anti-theft connector <2>
(b) Anti-theft connector <5> Body GND –
(c) Anti-theft connector <6> Anti-theft connector <2>
(d) Anti-theft connector <6> Body GND –
Regular : 5 V
Irregular : Large discrepancy from 5 V
RY9212166ELS0140US0
4-S126 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. Continuity check
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the anti-theft connector.
3. Disconnect the ECU connector.
4. Test the continuity based on the table below.
Mea-
sure- Connector Name (+ terminal side) Pin No. Connector Name (- terminal side) Pin No.
ment
(a) Anti-theft connector <1> ECU connector <49>
(b) Anti-theft connector <2> ECU connector <2>
(c) Anti-theft connector <3> ECU connector <59>
(d) Anti-theft connector <4> ECU connector <51>
(e) Anti-theft connector <5> ECU connector <41>
(f) Anti-theft connector <6> ECU connector <37>
Regular : Continuity
Irregular : No continuity
RY9212166ELS0141US0
4-S127 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[D] Testing the Equipment Itself
1. Inspecting the anti-theft antenna
[Measurement Conditions]
1. Key switch : OFF
2. Replace with a new antenna.
3. Select the tester mode and check the anti-theft antenna.
RY9212001ELS0205US0
2. Settings after replacing device
1. No settings required.
RY9212001ELS0013US0
3. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0003US0
4-S128 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[5] POWER SUPPLY SYSTEM
(1) Over Voltage
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
2. Press the info button (b) and check the additional content.
Ex.) Over voltage
(1) Over Voltage (a) Warning Lamp
Sys Err (b) Info Button
RY9212032ELS0027US0
Check whether the machine has been jump started with a 24 V
battery.
E.g.) Whether switched to 24V
(a) 12 V (b) 24 V
RY9212001ELS0207US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
An alternator recharging error is also possible.
Refer to the pages on the recharging system errors.
RY9212166ELS0142US0
4-S129 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(2) 5V Short System Error
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
2. Press the info button (b) and check the additional content.
Ex.) External 5 V
(1) External 5V (a) Warning Lamp
Sys Err (b) Info Button
RY9212032ELS0028US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
Testing the 3.5V line
(A) AI Console Connector (B) Travel Pressure Sensoe (C) Right Control Lever (D) Left Control Lever
Connector Connector Connector
[Test Conditions]
1. Check whether each line is pinched against or touching the body If the insulation is damaged, repair it properly
and check the meter display again.
RY9212166ELS0143US0
4-S130 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[6] COMMUNICATION SYSTEM
(1) CAN Communication Errors
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
2. Press the info button (b) and check the additional content.
EX.) CAN system (main)
• When a CAN communication error is displayed, the oil lamp (c)
and charging lamp (d) light up and the engine will not start.
(1) CAN Sys Err (a) Warning Lamp
(b) Info Button
(c) Oil Lamp
(d) Charging Lamp
RY9212032ELS0030US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
3. Tester mode
1. Select the tester mode.
2. Confirm the ECU is .
Regular Irregular
ECU (main) ×
ECU (AS) × ×
ECU (CRS) ×
(1) Meter / ECU display screen
RY9212166ELS0180US0
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Check whether the 5 A ECU main (+B) fuse is blown.
RY9212001ELS0219US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
4-S131 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
3. Causes of wiring disconnection
[Test Conditions]
1. Key switch: OFF
2. Engine ECU connector detached.
3. There is a disconnection somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (Pulling force not to exceed 3kgf)
If it comes off, plug the connector in securely and check the
ECU again in the tester mode.
RY9212166ELS0181US0
4. Causes of shorting
[Test Conditions]
1. Key switch: OFF
2. The wires of the main ECU connector, engine ECU connector,
meter connector or CAN comm. (2P) connector are pinched
against the body or in contact with the body.
If the insulation is damaged, repair it properly and check again
in the tester mode.
(a) Engine ECU Connector (c) CAN Communication (2P)
(b) Meter Connector Connector
RY9212166ELS0182US0
4-S132 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[C] Testing with a Circuit Tester
1. Continuity check
[Measurement Conditions]
1. Key switch: OFF
2. Disconnect the main ECU connector, the engine ECU connector, the meter connector and the CAN
communication (2P) connector.
3. Test the continuity based on the table below.
Mea-
sure- Connector name Pin No. Connector name Pin No.
ment
(1) Main ECU connector <60> Meter connector <5>
(2) Main ECU connector <79> Meter connector <6>
(3) Main ECU connector <60> Engine ECU connector <38>
(4) Main ECU connector <79> Engine ECU connector <39>
(5) Meter connector <6> CAN communication (2P) connector <1>
(6) Meter connector <5> CAN communication (2P) connector <2>
Regular: Continuity
Irregular: No continuity
RY9212166ELS0183US0
[D] Testing the Equipment Itself
1. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0032US0
4-S133 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[7] AUX SYSTEM
(1) AUX1 / AUX2/Thumb System Errors
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
2. Press the info button (b) and check the additional content.
Ex.) AUX1 Sys Err
(1) AUX1 Sys Err (a) Warning Lamp
(2) AUX2 Sys Err (b) Info Button
RY9212032ELS0048US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
3. Tester mode
1. Select the tester mode.
2. Start the engine.
3. Measure the voltage of AUX switch based on the table below.
Set value (ex.)
Indicated
Left Right Center At stop
value
(small) (large) (medium)
AUX1 knob
0.25 to 4.75 V 0.95 V 4.41 V 2.36 V 0V
switch
AUX2 /
Thumb knob 0.25 to 4.75 V 0.77 V 4.21 V 2.59 V 0V
switch
Output
0.5 to 2.0 A 0 to 0.2 A
current
Regular When cut off When shorted
AUX one way hold
↓
SW ON
AUX one way hold
↓
SW OFF
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
(1) AUX1 Knob (4) Control Lever (Left)
Current (5) AUX One Way Hold SW
AUX Hold SW (6) AUX2 / Thumb Knob
(2) Control Lever (Light) Current
(3) AUX One Way Hold SW AUX Hold SW
RY9212166ELS0144US0
4-S134 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Checking fuses is not necessary.
RY9212001ELS0008US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
3. Causes when a break in wiring
[Test Conditions]
1. Key switch : OFF
2. The AUX1 / AUX2 SOL connector is disconnected.
3. The AUX switch connector is disconnected.
4. There is a break somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (pull with a max of 3 kgf (30 N, 7 lbf) of force)
If it comes off, plug the connector back in securely and check the
AUX switch and AUX1 / AUX2 SOL again in the tester mode.
Criteria
Regular : no break
Irregular : has a break
(a) AUX1 SOL (High) (d) AUX2 SOL (Low)
(b) AUX1 SOL (Low) (e) AUX Switch Connector
(c) AUX2 SOL (High)
RY9212032ELS0050US0
4. Causes when a short
[Test Conditions]
1. Key switch : OFF
2. The AUX switch connector wire and/or AUX1 / AUX2 SOL wire
is pinched against or touching the body.
If the insulation is damaged, repair it properly and check the
AUX switch and AUX1 / AUX2 SOL again in the tester mode.
Criteria
Regular : no short
Irregular : shorted
(a) AUX1 SOL (High) (c) AUX2 SOL (High)
(b) AUX1 SOL (Low) (d) AUX2 SOL (Low)
RY9212032ELS0051US0
4-S135 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[C] Testing with a Circuit Tester
1. Voltage check (AUX one way hold Switch)
[Measurement Conditions]
1. Disconnect the AUX1 / AUX2 switch connector.
2. Key switch : ON
3. AUX one way hold Switch : ON
4. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
AUX1 / AUX2 switch AUX1 / AUX2 switch
(a) <5> <6>
connector connector
AUX1 / AUX2 switch
(b) <5> Body GND –
connector
Regular : 12 V
Irregular : Large discrepancy from 12 V
RY9212166ELS0145US0
2. Voltage check (AUX1 / AUX2 Switch)
[Measurement Conditions]
1. Disconnect the AUX1 / AUX2 switch connector.
2. Key switch : ON
3. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
AUX1 / AUX2 switch AUX1 / AUX2 switch
(a) <1> <2>
connector connector
AUX1 / AUX2 switch
(b) <1> Body GND –
connector
Regular : 5 V
Irregular : Large discrepancy from 5 V
RY9212166ELS0146US0
3. Continuity check (AUX one way hold Switch)
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the AUX1 / AUX2 switch connector.
3. Disconnect the ECU connector.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
AUX1 / AUX2 switch
(a) <5> ECU connector <11>
connector
AUX1 / AUX2 switch
(b) <6> ECU connector <69>
connector
Regular : Continuity
Irregular : No continuity
RY9212166ELS0147US0
4-S136 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
4. Continuity check (AUX1 / AUX2 Switch)
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the AUX1 / AUX2 switch connector.
3. Disconnect the ECU connector.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
L Lever L Lever
AUX1 / AUX2 switch <3> <29>
(a) ECU connector
connector R Lever R Lever
<3> <28>
AUX1 / AUX2 switch
(b) <1> ECU connector <11>
connector
AUX1 / AUX2 switch
(c) <2> ECU connector <10>
connector
Regular : Continuity
Irregular : No continuity
RY9212166ELS0148US0
5. Continuity check (AUX1 SOL)
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the ECU connector.
3. Disconnect the AUX1 SOL connector.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin NO. Pin NO.
(+ terminal side) (– terminal side)
ment
AUX1 SOL High <1> <23>
(a) ECU Connector
Connector Low <1> <24>
AUX1 SOL High <2>
(b) ECU Connector <19>
Connector Low <2>
Regular : Continuity
Irregular : No continuity
RY9212166ELS0149US0
4-S137 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
6. Continuity check (AUX2 SOL)
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the ECU connector.
3. Disconnect the AUX2 SOL connector.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin NO. Pin NO.
(+ terminal side) (– terminal side)
ment
High
AUX2 SOL <43>
(a) <1> ECU Connector
Connector
Low <1> <42>
High
AUX2 SOL <2>
(b) ECU Connector <16>
Connector
Low <2>
Regular : Continuity
Irregular : No continuity
RY9212166ELS0150US0
[D] Testing the Equipment Itself
1. Testing the AUX1 / AUX2 solenoid
[Test Conditions]
1. Key switch : OFF
2. Disconnect AUX1 / AUX2 solenoid connector from the machine
and test the solenoid separately.
3.2 ± 0.5 Ω
AUX1 / AUX2 solenoid Factory specification
(at 20 °C, 68 °F)
Criteria
Regular : no break
Irregular : has a break
(a) AUX1 / AUX2 Solenoid Terminals
RY9212166ELS0151US0
2. Settings after replacing device
1. No settings required.
RY9212001ELS0013US0
3. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0003US0
4-S138 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[8] ANGLE BLADE SYSTEM
(1) Angle Blade System Error
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red or not.
2. Press the info button (b) and check the additional content.
Ex.) Angle Sys Err
(1) Angle Blade Sys Err (a) Warning Lamp
(b) Info Button
RY9212166ELS0152US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
3. Tester mode
1. Select the tester mode.
2. Start the engine.
3. Put the machinery operation lever lock in the [Unlock] position.
4. Operate the angle blade switch and check the switch according
to the following table.
Regular When cut off When shorted
Angle Blade switch
ON
Angle Blade switch
OFF
Angle Blade
solenoid ON
Angle Blade
solenoid OFF
Criteria
Regular : no break
Irregular : has a break
Irregular : shorted
(1) Angle R SW (c) Unlock
Angle L SW (d) Lock
Angle R SOL (e) Machinery Operation Lever Lock
Angle L SOL
RY9212166ELS0200US0
4-S139 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Checking fuses is not necessary.
RY9212001ELS0008US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
3. Causes when a break in wiring
[Test Conditions]
1. Key switch : OFF
2. The angle blade switch connector is disconnected.
3. The angle blade solenoid connector is disconnected.
4. There is a break somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (pull with a max of 3 kgf (30 N, 7 lbf) of force) If it
comes off, plug the connector back in securely and check the angle
blade switch and angle blade solenoid in the tester mode.
Criteria
Regular : no break
Irregular : has a break
(a) Angle R Solenoid Connector (c) Angle Blade Switch Connector
(b) Angle L Solenoid Connector
RY9212166ELS0153US0
4. Causes when a short
[Test Conditions]
1. Key switch : OFF
2. The angle blade switch connector wire and/or angle blade
solenoid connector wire are pinched against or touching the
body.
If the insulation is damaged, repair it properly and check the
angle blade switch and the angle blade solenoid again in the
tester mode.
Criteria
Regular : no short
Irregular : shorted
(a) Angle R Solenoid Connector (c) Angle Blade Switch Connector
(b) Angle L Solenoid Connector
RY9212166ELS0154US0
4-S140 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[C] Testing with a Circuit Tester
1. Voltage check (angle blade switch)
[Measurement Conditions]
1. Disconnect the angle blade switch connector
2. Key switch : ON
3. Put the machinery operation lever lock in the [Unlock] position.
4. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Angle blade switch <1> Angle blade switch <3>
(a)
connector <1> connector <4>
Angle blade switch
(b) <1> Body GND –
connector
Regular : 12 V
Irregular : Large discrepancy from 12 V
RY9212166ELS0155US0
2. Voltage check (angle blade L solenoid)
[Measurement Conditions]
1. Disconnect angle blade L solenoid connector.
2. Key switch : ON
3. Put the machinery operation lever lock in the [Unlock] position.
4. Angle blade left switch : ON
5. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Angle blade L
(a) <1> Body GND –
solenoid connector
Angle blade L Angle blade L, R
(b) <1> <2>
solenoid connector solenoid connector
Regular : 12 V
Irregular : Large discrepancy from 12 V
(1) Angle Blade Control Switch (A) Turn the Right
(B) Turn the Left
RY9212166ELS0156US0
4-S141 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
3. Voltage check (angle blade R solenoid)
[Measurement Conditions]
1. Disconnect angle blade R solenoid connector.
2. Key switch : ON
3. Put the machinery operation lever lock in the [Unlock] position.
4. Angle blade right switch : ON
5. Measure the voltage based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Angle blade R
(a) <1> Body GND –
solenoid connector
Angle blade R Angle blade L, R
(b) <1> <2>
solenoid connector solenoid connector
Regular : 12 V
Irregular : Large discrepancy from 12 V
(1) Angle Blade Control Switch (A) Turn the Right
(B) Turn the Left
RY9212166ELS0157US0
4. Continuity check (angle blade switch)
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect angle blade switch connector and angle blade
solenoid connector.
3. Put the machinery operation lever lock in the [Unlock] position.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Angle blade switch
(a) <3> ECU connector <68>
connector
Angle blade switch
(b) <4> ECU connector <71>
connector
Regular : Continuity
Irregular : No continuity
RY9212166ELS0158US0
4-S142 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
5. Continuity check (angle blade L, R solenoid)
[Measurement Conditions]
1. Key switch : OFF
2. Disconnect the ECU connector.
3. Disconnect angle blade L, R solenoid connector.
4. Test the continuity based on the table below.
Mea-
Connector Name Connector Name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Angle blade L, R L<1> L<20>
(a) ECU connector
solenoid connector R<1> R<18>
Angle blade L, R L<2> –
(b) Body GND
solenoid connector R<2> –
Regular : Continuity
Irregular : No continuity
RY9212166ELS0159US0
[D] Testing the Equipment Itself
1. Testing the angle blade solenoid
[Test Conditions]
1. Key switch : OFF
2. Disconnect angle blade solenoid connector from the machine
and test the solenoid separately.
Lever lock solenoid Factory specification 12 Ω ± 10 %
Criteria
Regular : no break
Irregular : has a break
(a) Angle Blade Solenoid Terminals
RY9212166ELS0160US0
2. Settings after replacing device
1. No settings required.
RY9212001ELS0013US0
3. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212032ELS0003US0
4-S143 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[9] EP SYSTEM
(1) EP System Errors
[A] Checking the Meter Panel
1. Information displayed on the meter panel
1. Check whether or not the warning lamp (a) on the panel is
blinking red.
2. Press the info button (b) and check the additional content.
Example) EP Solenoid
(1) EP Sys Err (a) Warning Lamp
(b) Info Button
RY9212166ELS0184US0
2. Reading the failure history
1. Select the failure history read mode.
2. Read the failure history and check the date (y/m/d) and hour
meter of the last occurrence.
E.g.) The last failure record was February 6, 2009 at 37 hours.
(a) Failure (c) The Last Breakdown Date (y/m/d)
(b) Number of Failure and Hour Meter.
RY9212032ELS0001US0
3. Tester mode
1. Select the tester mode.
2. Start the engine.
3. Put the machine's lever lock in the release position and press
the EP switch.
4. Operate the EP switch and check the EP switch and the EP
solenoid based on the table below.
5. Put the excavator in travel and check that the travel pressure
sensor reading changes.
Regular If disconnected If shorted
Boom up pressure
switch (during boom
up operation)
Boom up pressure
switch (other than
above)
EP SW ON
EP SW OFF
Factory
Mode Use conditions
specification
A/C OFF 0A
P mode
EP so- A/C ON 0.6 A
lenoid During travel or boom up operation 0.94 A
E mode
Other than above 1.65 A
Design Value Regular If disconnected If shorted
Travel pressure Current value 0V Not stable
(1) Boom Up Pressure Switch, EP (a) EP Switch
Switch/Solenoid Display Screen
(2) Travel Pressure Display Screen
RY9212166ELS0185US0
4-S144 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
[B] Inspecting each Device Visually and Physically
1. Checking fuses
1. Checking fuses is not necessary.
RY9212001ELS0008US0
2. Checking relays
1. Checking relays is not necessary.
RY9212001ELS0009US0
3. Causes of wiring disconnection
[Test Conditions]
1. Key switch: OFF
2. EP solenoid connector detached.
3. Travel pressure sensor connector detached.
4. Boom up pressure switch connector detached.
5. There is a disconnection somewhere in the wiring.
Pull on the harness and make sure the connector/harness does
not come off. (Pulling force not to exceed 3kgf)
If it comes off, plug the connector back in securely and check
again in the tester mode.
(a) EP Solenoid Connector
RY9212166ELS0186US0
4. Causes of shorting
[Test Conditions]
1. Key switch: OFF
2. The wires of the EP solenoid connector, travel pressure sensor
connector and boom up pressure switch connector are pinched
against the body or touching the body.
If the insulation is damaged, repair it properly and check the EP
solenoid, travel pressure sensor and boom up pressure switch
again in the tester mode.
(a) Travel Pressure Sensor (b) Boom Up Pressure Switch
Connector Connector
RY9212166ELS0187US0
[C] Testing with a Circuit Tester
(A) EP Switch
1. Voltage check
[Measurement Conditions]
1. Disconnect the EP switch connector.
2. Key switch: ON
3. Measure the voltage based on the table below.
Mea-
Connector name Connector name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) EP switch <7> EP switch <6>
(b) EP switch <7> Ground –
Regular: 12V
Irregular: Large deviation from 12V
RY9212166ELS0188US0
4-S145 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. Continuity check
[Measurement Conditions]
1. Disconnect the EP switch connector and the main ECU
connector.
2. Key switch: OFF
3. Check for continuity based on the table below.
Mea-
Connector name Connector name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) EP switch <7> Main ECU <76>
(b) EP switch <6> Main ECU <65>
Regular: Continuity
Irregular: No continuity
RY9212166ELS0189US0
(B) EP SOL
1. Voltage check
[Measurement Conditions]
1. Disconnect the EP solenoid connector.
2. Key switch: ON
3. Measure the voltage based on the table below.
Mea-
Connector name Connector name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) EP solenoid <1> EP solenoid <2>
(b) EP solenoid <1> Body GND –
Regular: 12V
Irregular: Large deviation from 12V
RY9212166ELS0190US0
2. Continuity check
[Measurement Conditions]
1. Remove the EP solenoid connector and the main ECU
connector.
2. Key switch: OFF
3. Check for continuity based on the table below.
Mea-
Connector name Connector name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) EP solenoid <1> Main ECU <22>
(b) EP solenoid <2> Main ECU <21>
Regular: Continuity
Irregular: No continuity
RY9212166ELS0191US0
4-S146 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
(C) Travel Pressure Sensor
1. Voltage check
[Measurement Conditions]
1. Disconnect the travel pressure switch connector.
2. Key switch: ON
3. Measure the voltage based on the table below.
Mea-
Connector name Connector name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Travel pressure Travel pressure
(a) <1> <3>
sensor sensor
Travel pressure
(b) <1> Body GND –
sensor
Regular: 5V
Irregular: Large deviation from 5V
RY9212166ELS0192US0
2. Continuity check
[Measurement Conditions]
1. Disconnect the travel pressure switch connector and the main
ECU connector.
2. Key switch: OFF
3. Test the continuity based on the table below.
Mea-
Connector name Connector name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
Travel pressure
(a) <1> Main ECU <11>
sensor
Travel pressure
(b) <2> Main ECU <53>
sensor
Travel pressure
(c) <3> Main ECU <10>
sensor
Regular: Continuity
Irregular: No continuity
RY9212166ELS0193US0
(D) Boom Up Switch
1. Voltage check
[Measurement Conditions]
1. Disconnect the boom up switch connector.
2. Key switch: ON
3. Measure the voltage based on the table below.
Mea-
Connector name Connector name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) Boom up switch <1> Boom up switch <2>
(b) Boom up switch <1> Body GND –
Regular: 5V
Irregular: Large deviation from 5V
RY9212166ELS0194US0
4-S147 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
2. Continuity check
[Measurement Conditions]
1. Disconnect the boom up switch connector and the main ECU
connector.
2. Key switch: OFF
3. Test the continuity based on the table below.
Mea-
Connector name Connector name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) Boom up switch <1> Main ECU <76>
(b) Boom up switch <2> Main ECU <66>
Regular: Continuity
Irregular: No continuity
RY9212166ELS0195US0
[D] Testing the Equipment Itself
1. Testing the EP switch
[Test Conditions]
1. Key switch: OFF
2. Disconnect the EP switch connector from the machine, press
the switch and measure separately.
Mea-
Connector name Connector name
sure- Pin No. Pin No.
(+ terminal side) (- terminal side)
ment
(a) EP switch <7> EP switch <9>
(b) EP switch <6> EP switch <7>
Mea-
sure- Connector name Pin No. Factory specification
ment
(c) EP switch <4> – <10> 680 Ω ±10 %
Regular: Continuity
Irregular: No continuity
A : Push
RY9212166ELS0196US0
2. Testing the EP solenoid
[Test Conditions]
1. Key switch: OFF
2. Disconnect the EP solenoid connector from the machine and
test the solenoid separately.
3.3 to 0.5 Ω
EP solenoid Factory specification
[20°C (68°F)]
Regular: Within factory spec
Irregular: Outside factory spec.
RY9212166ELS0197US0
4-S148 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
3. Inspecting the travel pressure sensor
[Test Conditions]
1. Key switch: OFF
2. Disconnect the travel pressure sensor connector from the
machine and test the travel pressure sensor independently.
Mea-
sure- Connector name Pin No. Factory specification
ment
Travel pressure
(a) <2> – <3> 23 kΩ ±1.0 kΩ
switch
Regular: Within factory spec
Irregular: Outside factory spec.
RY9212166ELS0198US0
4. Inspecting the boom up pressure switch
[Test Conditions]
1. Key switch: OFF
2. Remove the boom up pressure switch from the control valve,
attach a pressure gauge and test the pressure.
[Measurement Conditions]
• Engine RPM MAX
• Right pilot lever up operation
Resistance between
Operating pressure Switch
terminals
2.45 ± 0.3 MPa OFF 100 MΩ or higher
1.96 ± 0.3 MPa ON 1.0 Ω
Boom up pressure switch normally close (normally ON)
Regular: Within factory spec
Irregular: Outside factory spec.
RY9212166ELS0199US0
Boom up pressure switch
9.8 to 14.7 N·m
Tightening torque Switch (pressure, 25K) 1.0 to 1.5 kgf·m
7.2 to 10.8 lbf·ft
(1) M10 x P1.25
RY9212166ELS0161US0
5. Erasing failure history
1. After completing repairs, select Erase Failure History and erase
the records.
2. After erasing the records, read the failure history again and
make sure there are no failures.
Criteria
Regular : Failure history erased
Irregular : failure history not erased
(1) No Fail Record
RY9212166ELS0162US0
4-S149 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
7. DEALER SETTING MODE FLOWCHART
4-S150 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
4-S151 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM ELECTRICAL SYSTEM
4-S152 KiSC issued 04, 2021 A
5 CABIN
KiSC issued 04, 2021 A
MECHANISM
CONTENTS
1. AIR CONDITIONING SYSTEM .................................................................................................. 5-M1
[1] STRUCTURE ....................................................................................................................... 5-M1
[2] HOW THE MECHANISMS OF THE SYSTEM WORK ......................................................... 5-M3
[3] COMPRESSOR.................................................................................................................... 5-M4
[4] AIR CONDITIONING UNIT................................................................................................... 5-M7
[5] CONDENSER..................................................................................................................... 5-M12
[6] RECEIVER ......................................................................................................................... 5-M13
[7] PRESSURE SWITCH......................................................................................................... 5-M14
[8] SYSTEM CONTROLS ........................................................................................................ 5-M15
[9] ADJUSTING THE AIR FLOW AND DIRECTION ............................................................... 5-M16
[10]ELECTRICAL SYSTEM...................................................................................................... 5-M17
(1) Electrical Circuits .......................................................................................................... 5-M17
(2) Relays........................................................................................................................... 5-M18
(3) Blower Switch ............................................................................................................... 5-M19
2. WIPER ...................................................................................................................................... 5-M20
[1] WIPER SWITCH................................................................................................................. 5-M20
[2] WIPER ................................................................................................................................ 5-M20
[3] WIPER MOTOR ................................................................................................................. 5-M21
KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
1. AIR CONDITIONING SYSTEM
[1] STRUCTURE
(1) Control Panel (4) Cabin Air Inlet (7) Air Conditioning Unit (10) Receiver
(2) Outside Air Inlet (5) In/Outside Air Duct (8) Compressor (11) Heater Core
(3) Outside Air Duct (6) Air Duct ASSY (9) Condenser
The cabin is equipped with a high-capacity, low-profile air conditioner that can circulate cabin air or bring in fresh
air from outside.
Cabin air is sucked into the cabin air inlet (4), which is located behind the seat; it then passes through the
in/outside air duct (5) to the air conditioning unit (7) (cabin air circulation). Fresh air is taken in via the outside air inlet
(2) and passes through the in/outside air duct (5) and enters the air conditioning unit (7) (fresh air intake).
The inside or outside air that is sucked into the air conditioning unit (7) is cooled and dehumidified by the cooler of
the air conditioning unit (7).
When the system is used for heating, the air is heated by the heater core (11) and then expelled from the air duct
ASSY (6). The vents installed inside the cabin can be opened and closed as well as adjusted to blow in different
directions.
(To be continued)
5-M1 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(Continued)
Cooling Capacity 3.4 kW ±10 %
Heating Capacity 4.1 kW ±10 %
R134a
Type of Refrigerant
0.65 to 0.75 kg
(charge capacity)
1.43 to 1.65 lbs
Factory
specification 0.196 MPa
Pressure Sensor (Low) 2.0 kgf/cm2
28.4 psi
3.14 MPa
Pressure Sensor (High) 32.0 kgf/cm2
455 psi
RY9212001CAM0001US0
5-M2 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
[2] HOW THE MECHANISMS OF THE SYSTEM WORK
(1) Capillary Tube (Heat Sensitive (7) Condenser A : Cooled Air E : High Pressure/Temperature
Capillary Tube) (8) Receiver B : Low Pressure and Gas
(2) Expansion Valve (9) Dryer Temperature Vapor F : Hot Air
(3) Evaporator (10) Pressure Switch C, D : Air Passes Through G : Liquid
(4) Blower Motor (11) Heater Core In / Outside Air Filter
(5) Compressor (12) Hot Water Valve
(6) Engine Cooling Fan
This air conditioning system works as follows.
1. Refrigerant passes through the evaporator (3), is vaporized and then is compressed by the compressor (5) to
approximately 1.47 MPa (15 kgf/cm2, 210 psi) and raised to a temperature of approximately 70 °C (158 °F) the
refrigerant is then sent in this state to the condenser (7).
2. The vaporized refrigerant passes through the condenser (7), where it is cooled down to approximately 50 °C
(122 °F) and the refrigerant changes back from a vapor to a liquid; it is then sent on to the receiver (8).
Then the heat from inside the cabin that is captured by the condenser (7) is released outside the cabin.
3. The liquid refrigerant collects in the receiver (8) and any moisture is removed from the refrigerant by the dryer (9).
4. The liquid refrigerant then passes on to the expansion valve (2), where it is sprayed through the small holes in
the valve into the evaporator (3), which produces a mist of the refrigerant; its pressure and temperature drop and
the refrigerant evaporates.
5. The refrigerant simultaneously captures heat from the surface of the evaporator's (3) pipes and evaporates
vigorously at 0 °C (32 °F).
6. As this happens, warm air from inside the cabin is drawn into the evaporator (3) by the blower motor (4) and the
refrigerant captures the heat and evaporates. In this way the air in the cabin is cooled.
[NOTE]
• Because the warm air inside the cabin is cooled quickly, the moisture in the air condenses. In other words,
the air in the cabin can be dehumidified.
7. The refrigerant vaporized in the evaporator (3) is returned to the compressor (5) and compressed, changing it
back into a liquid. In doing so, the refrigerant is put under high pressure and temperature.
8. The air that passed through the evaporator (3) can be adjusted to the desired temperature by then passing it
through the heater core (11). Engine coolant is heated by the engine and the amount of the coolant that flows into
the heater core (11) is controlled by the hot water valve (12), and this adjusts the temperature of the air that flows
through the heater core (11).
RY9212001CAM0002US0
5-M3 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
[3] COMPRESSOR
The vane type of compressor installed in this system
is composed of a cylinder (1) that is elliptical in
cross-section, along with five vanes (3) attached to the
rotor (2). This vane compressor has two each of intake
and discharge ports.
The five vanes (3) are attached to the rotor (2) and
as it rotates, the tips of the vanes come in contact with
the walls of the cylinder (1) and an airtight compression
space is maintained both by the centrifugal force exerted
by the rotor (2) along with the back pressure on the
vanes (3), which is in proportion to the rpms of the rotor
(2).
As a result, the volume changes in each of the five
segments of the cylinder, which are divided by the five
vanes (3) in the cylinder (1).
Each time that the rotor (2) rotates, each of the five
segments of the cylinder goes through two cycles of
intake, compression and discharge.
(1) Cylinder (3) Vane
(2) Rotor
RY9212001CAM0003US0
How it Works
As the rotor (3) turns, the volume of space in a
segment, as divided by the cylinder (1) and vanes (4),
increases, sucking refrigerant gas from the intake port
(2) into the cylinder space.
As the rotor (3) turns further, the volume of the space
created between the cylinder (1) and vanes (4)
decreases, compressing the refrigerant gas. As the rotor
(3) continues to turn, the refrigerant gas is compressed
further, putting it under a great deal of pressure, pressing
on the discharge valve and opening it. The refrigerant
gas is then expelled via the discharge port (5).
(1) Cylinder (A) Compression Cycle
(2) Intake Port (B) Discharge Cycle
(3) Rotor (C) Intake Cycle
(4) Vane
(5) Discharge Port
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Compressor Oil
The compressor oil is dissolved in the refrigerant and circulates throughout the entire cooling system acting as
the lubricating oil for the compressor. However, because the previously used R12 compressor oil does not dissolve
in R134a, it does not circulate through the cooling cycle. So it drastically reduces the working life of the compressor.
As a result, it is imperative that the right compressor oil is always used. The mineral oil that is used in an R12
cooling system cannot be used in an R134a cooling system. A synthetic PAG oil has to be used in an R134a cooling
system. This oil mixes extremely well with refrigerant gas and provides the entire system with the optimum lubrication.
Volume of Oil Product Name
110 to 120 cc
0.116 to 0.127 U.S.qts ND–OIL8 <PAG* oil>
0.098 to 0.106 lmp.qts
*PAG : Polyalkylene glycol (synthetic oil)
RY9212001CAM0005US0
5-M4 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Magnetic Clutch
A magnetic clutch is a device that governs the
mechanical linkage between the engine and the
compressor. When the engine is rotating and the A/C
switch is on, air at cabin temperature comes out and
when the temperature reaches the temperature set with
the temperature control switch, or when the cabin gets
hot, the clutch works to stop or to drive the compressor,
respectively.
The hub of the magnetic clutch is attached to the
compressor shaft and when it is not driving the
compressor, it is separate from the rotor and just the
pulley turns. When the A/C switch is turned on, current
flows into the stator coil, making the stator into a magnet,
which then holds onto the hub and the pulley turns along
with the compressor.
(1) Pressure Plate (5) Rotor w/ Pulley
(2) Ball Bearing (6) Stator
(3) Snap Ring (7) Snap Ring
(4) Pulley
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B. Safety Valve
The valve opens when the refrigerant pressure
reaches the specified pressure, thus relieving the
pressure. When the pressure becomes abnormally high,
it overcomes the force of the spring, allowing refrigerant
to leak out of the relief port; when the pressure drops the
reverse happens--the spring overcomes the pressure
and the safety valve closes. When an error occurs, this
also keeps the discharge of refrigerant to a minimum.
(1) Safety Valve a : 113 L/min.
(27.2 U.S.gals./min.,
(A) Refrigerant Leak Route 24.86 lmp.gals./min.)
(B) Functional Characteristics b : 2.75 MPa
(C) Amount of Refrigerant (28.1 kgf/cm2, 399.7 psi)
Leaked c : 3.43 MPa
(D) Pressure (35.0 kgf/cm2, 497.8 psi)
d : 4.12 MPa
(42.0 kgf/cm2, 598.0 psi)
RY9212001CAM0007US0
5-M5 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Temperature Sensor
A temperature sensor is installed on the head of the
vane type of compressor. This sensor detects the
temperature of the refrigerant and when the refrigerant
becomes unusually hot, it cuts off the magnetic clutch,
stopping the compressor. The temperature sensor is
composed of a bimetallic strip and contacts. A bimetallic
strip is a sandwich of two metals with different rates of
expansion and it bends when heated due to these
different rates of expansion. This characteristic is
exploited when there is an excessive temperature via the
rod, which breaks the contact and switches the magnetic
clutch off.
153 to 163 °C
OFF
307 to 325 °F
Operating Ranges
120 ± 5 °C
ON
248 ± 41 °F
11.8 ± 1.47 N·m
Temperature
Tightening torque 1.2 ± 0.15 kg·fm
Sensor
8.7 ± 1.08 lbf·ft
(1) Temperature Sensor A : Contact
(2) Compressor B : Bimetallic Strip
C : Rod
(a) To battery + Terminal
RY9212001CAM0008US0
5-M6 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
[4] AIR CONDITIONING UNIT
(A) Diagram of Linkages and
Electrical Parts
The diagram above was created for general explanations of the air conditioning unit, so it may differ from the air
conditioning unit installed in the machine covered by this workshop manual. Similarly, this does not guarantee the
parts used inside the air conditioning unit are the same.
The air conditioning unit is composed of an evaporator, an expansion valve, a heater core, a blower, etc.
No. Name of part No. Name of part No. Name of part
(1) Upper case (10) Bolt (19) O-Ring
(2) Side cover (11) Fin thermistor (20) Servo motor
(3) Lower case (12) Clamp (21) Linkage lever
(4) Linkage cover (13) A/C Amp (22) Blower resistor
(5) Intake cover (14) Heater core (23) Self-tapping screw
(6) Evaporator (15) Pipe (24) Self-tapping screw
(7) O-Ring (16) Hot water valve (25) Cap
(8) O-Ring (17) Pipe clip (26) Blower motor
(9) Expansion valve (18) Screw (27) Wire harness
RY9212148CAM0001US0
5-M7 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Evaporator
The evaporator takes the refrigerant, which has been
made liquid by the condenser and cooled and put under
low-pressure by the expansion valve, and by
evaporating it, the heat and humidity of the air passing
through the evaporator is removed, thus producing cool,
dehumidified air.
(a) Fins (A) Inlet
(b) Tubes (B) Outlet
RY9212001CAM0010US0
Heater Core
The heater core dissipates the heat of the heated
engine coolant. So, the air that is blown through it by the
blower motor passes through the fins of the heater core
and the air takes on the heat of the coolant.
(1) Heater Core (A) Inlet
(B) Outlet
RY9212001CAM0011US0
Blower
The blower is built into the right side of the A/C unit.
The blower forces cool, warm or fresh outside air through
the vents into the cabin.
The rpm of the blower motor can be adjusted to three
levels with the blower resistor. The blower fan is the type
that uses centrifugal force and it sucks in air parallel to
its axis of rotation and blows it out perpendicular to the
centrifugal force, or in other words, perpendicular to the
axis of rotation.
Specifications (at 20 °C)
Model DC Ferrite
Rated Voltage 12 V
No load RPM 4300 ± 400 rpm
No load amperage 1 to 3 A
Direction of rotation
Left
(viewed from drive side)
Rated load torque 461 N·m, 47.0 kgf·m, 340 lbf·ft
RPM 2800 ± 280 rpm
Amperage 18.3 ± 1.8A
(1) Blower (A) Circuit Diagram
(a) (+) Terminal
(b) (-) Terminal
RY9212001CAM0012US0
5-M8 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Blower resistor
Acts as the blower switch and controls the rpm of the
blower motor by switching the degree of resistance.
The fan speed can be switched to three levels, 1, 2 and
3, with 3 being the fastest.
(1) MI (A) Blower Resistor
(2) HI (B) Wiring Diagram
(3) LO
(4) Blank
RY9212166CAM0004US0
5-M9 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Expansion Valve
[Functions]
The expansion valve works in the following two
ways.
1. By spraying the liquid refrigerant, which is hot and
under high pressure, it makes it expand rapidly,
producing a low-temp, low-pressure refrigerant
vapor.
2. It adjusts the amount of refrigerant according to the
vaporized state of the refrigerant in the evaporator.
In order to take full advantage of the capabilities of
the evaporator, a state must always be maintained in
which the liquid refrigerant takes on the ambient
heat, then it is completely vaporized at the outlet of
the evaporator. In order to do so, the expansion
valve automatically adjusts the volume of refrigerant
in response to changes in the cabin temperature
(cooling load) and changes in the compressor RPM.
[Structure (box type)]
• The expansion valve is composed of a diaphragm,
heat-sensing rod, and a needle valve (ball) and the
refrigerant gas is enclosed upstream of the
diaphragm. The downstream side of the diaphragm
is pressurized by the evaporator outlet pressure.
[How it Works]
• The heat-sensitive rod senses the temperature of the
refrigerant passing to the evaporator and the
temperature at that point is communicated to the
refrigerant gas on the upstream side of the
diaphragm via the heat-sensitive rod. As such, the
pressure of the gas varies with the temperature, thus
moving the heat-sensitive rod directly connected to
the diaphragm and adjusting the opening of the
needle valve.
Evaporator outlet temperature Operation
The pressure of the gas in the diaphragm chamber drops, reducing the volume and moving the
When low (when cooling load is low) heat-sensitive rod to the right, which constricts the needle valve and reduces the flow of refrigerant
to the evaporator.
The pressure of the gas in the diaphragm chamber rises, increasing the volume and moving the
When high (when cooling load is high) heat-sensitive rod to the left, which opens the needle valve and supplies more refrigerant to the
evaporator.
(1) Evaporator A : Diaphragm D : Body (a) From Receiver
B : Heat-Sensitive Rod E : Needle Valve (Hi-Pressure)
C : Spring (b) To Compressor
(Lo-Pressure)
(c) To Evaporator
(d) From Evaporator
RY9212001CAM0014US0
5-M10 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Fin Thermistor (for frost control)
[Function]
Senses the temperature of the fins of the evaporator
and when they are too cold, it stops the compressor and
prevents frost from forming before it happens.
[How it Works]
The sensor of the fin thermistor senses the
evaporator's fin temperature and if the resistance inside
the sensor exceeds the thermo-amp resistance setting,
its internal circuit shuts off the power to the compressor
clutch.
Specifications
Rated Voltage DC12 V
Measurement
DC13 ±0.2 V at 25 ± 5 °C (77 ± 9 °F)
Conditions
OFF R1 4383 ±131 Ω (2 °C, 36 °F)
Temperature
ON R2 (4095 Ω) (3.35 °C, 38 °F)
Detection
Hysteresis 215 ±5.0 Ω (1 °C, 34 °F)
Usage Conditions
Temperature
–30 to 80 °C (–22 to 176 °F)
Range
Voltage Range DC10 to 16 V
Operating Voltage
DC8 to 16 V (at 25 °C, 77 °F)
Range
Temperature 10 °C 15 °C 20 °C 25 °C 30 °C
Detection / 50 °F / 59 °F / 68 °F / 77 °F / 86 °F
2.96 2.34 1.87 1.50 1.22
Resistance Value
kΩ kΩ kΩ kΩ kΩ
(1) Fin Thermistor (a) Evaporator Fin
(2) Thermo-Amp Temperature Detector
RY9212001CAM0015US0
Hot Water Valve
The hot water valve is the valve that adjusts the
volume of engine coolant that flows into the heater core,
and this adjustment changes the temperature of the
heater core and thus controls the temperature of air
flowing through it.
(a) Open (MAX Hot) (c) Inlet
(b) Closed (MAX Cool) (d) Outlet
RY9212001CAM0016US0
5-M11 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Servo Motor (for adjusting temperature)
The servo motor is composed of a motor, a
potentiometer, movable contacts, etc., and operates
according to signals from the A/C's CPU.
The servo motor uses a DC ferrite motor and rotates
forward and reverse. Its potentiometer also uses
variable resistance and changes the resistance value
according to the operating angle.
The servo motor and the hot water valve are linked
via a linkage lever and turning the temperature control
dial on the control panel opens/closes the hot water
valve and adjusts the temperature of air vented inside
the cabin.
Specifications (at 20 °C, 68 °F)
Model DC Ferrite
Rated Voltage 12 V
Rated load torque 0.3 N·m, 0.03 kgf·m, 0.2 lbf·ft
RPM 3.5 to 5.5 rpm
Amperage 0.02 to 0.10 A
Potentiometer Linearity ±3%
Impressed Voltage Terminals 6 (POS.2) 7 (POS.1)
(1) Servo Motor (A) Potentiometer Output
(2) Linkage Lever Schematic
(3) Hot Water Valve (a) Voltage (V)
(b) Operating Angle 60 °
(c) MAXCOOL
(d) MAXHOT
(e) CW
RY9212001CAM0017US0
[5] CONDENSER
The hot, compressed refrigerant is under high
pressure and in a gaseous state; the condenser cools it
and returns it to a liquid state. In the interval between
entering and passing through the condenser, the
refrigerant is cooled and becomes liquid refrigerant
again. At this point, it is necessary to be sure the
refrigerant is liquid at the outlet of the condenser. If the
refrigerant is not condensed enough in the condenser
some refrigerant would be in a gaseous state and that
would reduce the A/C's cooling efficiency.
(1) Tubes (a) Gaseous Refrigerant
(2) Fins (b) Liquid Refrigerant
(3) Vapor (c) Inlet (70 °C, 158 °F)
(4) Vapor/Liquid Mix (d) Outlet (50 °C, 122 °F)
(5) Liquid
RY9212001CAM0018US0
5-M12 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
[6] RECEIVER
The receiver is composed of a receiver tank, dryer,
strainer and a receiver tube.
[Receiver Tank]
In the A/C system, the rpm of the compressor
changes in response to changes in the engine rpm, so
the appropriate amount of refrigerant in the cooling
circuit also changes. The receiver tank is the part that
reacts to those changes; when a lot of refrigerant is not
required in the cooling circuit, excess refrigerant is
stored temporarily in the tank and when more coolant is
needed, it is supplied to the circuit via the receiver tube.
It also acts to store the balance of refrigerant
charges and for extra refrigerant to counteract the leak
of small amounts of refrigerant, such as via permeation
of rubber hoses.
[Dryer]
If any moisture exists in the cooling circuit, it
damages the system by deteriorating the valves of the
compressor, its oil, by corroding metal parts in the circuit,
and/or freezes in the expansion valve and blocks the
circuit. The A/C system uses synthetic zeolite as a dryer
that is compatible with the circuit, and it absorbs any
moisture that gets mixed into the circuit during
installation or charging of refrigerant.
If the expansion valve freezes up frequently due to
moisture (icing), it means the dryer has lost its ability to
absorb it, so the receiver has to be replaced.
[Strainer]
If dirt gets into the cooling circuit, it blocks the
expansion valve, damages the compressor and
otherwise hampers its cooling function. The strainer
works to prevent any dirt flowing in the refrigerant from
going any further. The strainer cannot be cleaned, so
when it becomes severely clogged up, (in which case the
high pressure gets high, low pressure gets low), the
receiver has to be changed.
[Sight Glass]
The sight glass is mounted at the receiver joint on
top of the receiver and it is the only place in the circuit
where the amount of refrigerant can be visually
inspected.
(1) Dryer (A) Refrigerant Inlet
(2) Receiver Tube (B) Refrigerant Outlet
(3) Strainer
(4) Receiver Tank
RY9212001CAM0019US0
5-M13 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
[7] PRESSURE SWITCH
This dual type of switch detects unusually high and
low pressures in the cooling cycle. If the pressure gets
abnormally high or, due to a leak, abnormally low, it may
damage the equipment or deteriorate the lubricating
ability of the compressor oil, leading to scorching and
breakdown. To prevent these kind of problems from
occurring, the switch cuts the power to the compressor
clutch and stops the compressor.
Refrigerant
Operation
pressure
No increase in
The refrigerant pressure becomes less
pressure state
than the force of the spring, so the spring
(A) (when
presses the plate up and the upper contact
abnormally
opens (OFF).
low)
The refrigerant pressure is greater than the
Contact ON
force of the spring, so the pressure plate is
(B) (normal
pressed down, which presses the upper
operation)
contact down, closing the contact (ON).
The refrigerant pressure becomes greater
Contact OFF than the force of the plate spring and the
(C) (abnormally plate spring pushes down on the pin, which
high pressure) press on the lower contact, opening it
(OFF).
(1) Diaphragm a : 0.19 MPa
(2) Plate Spring (2.0 kgf/cm2, 28.4 psi)
(3) Pin b : 3.14 MPa
(4) Plate (32 kgf/cm2, 455 psi)
(5) Contact D : OFF
(6) Spring E : ON
(7) Terminal P : Pressure
PS : Pressure Switch
RY9212001CAM0020US0
5-M14 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
[8] SYSTEM CONTROLS
Control Panel
AC Switch (AC specification)
Press this switch [ON] to use the AC. When the AC
is [ON], the indicator lamp lights up. Press the switch
again to turn it [OFF].
Temperature Control Dial
Turning the dial to the left to cool, to the right for heat.
Fan Switch
The fan can be switched to 3 different speeds. The
strongest speed is [3].
[Operating the AC]
Heating
1. Adjust the fan switch and the temperature control
dial to the desired temperature.
NOTE
• When not using the heater in the summer, turn
the temperature control dial all the way to the left
(cool air side) so hot air does not raise the cabin
temperature.
Dry Heat
1. Press the AC switch to operate the AC.
2. Turn the fan switch to operate the fan.
3. Turn the temperature control dial to the right (warm
air) and adjust the air temperature.
NOTE
• Keep the door closed while operating the AC.
Cooling
1. Press the AC switch to operate the AC.
2. Turn the fan switch to operate the fan.
3. Turn the temperature control dial to the left (cool air)
and adjust the air temperature.
NOTE
• The moisture from dehumidifying the cabin
collects in the AC unit and is expelled outside the
machine.
• The idle boost function operates when the
compressor is operating.
Defrost
To eliminate fog or frost from the front window,
1. open the front vents and point them toward the front
window.
2. Turn the fan switch to [3] and the temperature control
dial to the right (warm air).
(1) Temperature Control Dial (3) AC Switch
(2) Indicator Lamp (4) Fan Switch
RY9212001CAM0021US0
5-M15 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
[9] ADJUSTING THE AIR FLOW AND DIRECTION
Air Flow
The air flows inside the cab as in the diagram.
The ideal condition can be achieved by adjusting the 6
vents.
(A) Front Window (D) Side
(B) Chest (E) Rear
(C) Feet
RY9212001CAM0022US0
Adjusting Air Direction
Front vent
Air vents can be adjusted in whatever direction you
desire. To use a vent as a defroster (stop the front
window from fogging up), point the vent toward the front
window.
(1) Front Vent (A) Front Window
(2) Cabin Air Inlet (Cab Air Filter) (B) Chest
(C) Feet
RY9212001CAM0023US0
5-M16 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
[10] ELECTRICAL SYSTEM
(1) Electrical Circuits
(1) Battery (13) Blower Switch (Shorting Type) (A) Fixed Voltage Circuit (h) (Free)
(2) Slow-Blow Fuse (80A) (14) Compressor Clutch Relay (B) Servo Motor Drive Circuit (i) Servo Motor Output1
(3) Slow-Blow Fuse (50A) (15) Pressure Switch (C) CPU (COOL Output)
(4) Fuse (5A) (16) Compressor Magnetic Clutch (D) Electronic Thermo Amp (j) (Free)
(5) Fuse (10A) (17) Fin Thermistor (Frost Sensor) (k) Servo Motor Output2
(6) Fuse (30A) (18) Indicator Lamp (a) Potentiometer Signal (HOT Output)
(7) Start Switch (19) AC Switch (b) ILL– (l) (Free)
(8) Power Relay (20) Volume (Temperature Setting) (c) Potentiometer Power (m) (Free)
(9) Work Light Switch (21) Servo Motor (d) Blower Motor (n) Headlight Switch
(10) Blower Motor Relay (e) Potentiometer GND (o) IG
(11) Blower Motor (f) Electronic Thermo (p) +B power
(12) Blower Resistor (g) GND
The processes up to the compressor's magnetic clutch engaging are indicated below.
1. Start switch → power relay ON → blower motor relay ON → blower switch ON (LO, MI or HI) →blower motor ON
2. AC switch ON (indicator lamp lights up) → pressure switch ON → fin thermistor ON →
compressor clutch relay ON → compressor magnetic clutch ON (compressor operates)
RY9212166CAM0001US0
5-M17 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(2) Relays
Current flows in the components of the AC system to
the blower motor and compressor's magnetic clutch. If all
of the current were supplied via the main switch, the
current would be too much for the switch, so the contacts
of the main switch would be in danger of burning out.
Similarly, if this current flowed directly from the battery
and the operator forget to turn the blower motor off, the
battery would discharge.
The system is equipped with relays in order to
prevent these kind of problems. When the current flows
through the coils of these relays, their contacts close,
allowing electricity to be supplied from the battery. By
adopting these relays, only a tiny amount of current is
needed to operate the relays, so very little current flows
through the main switch. As a result, the concern over its
contacts burning out is eliminated and when the main
switch is open, the relays' contacts open at the same
time. When this occurs, the flow of electricity in the AC
circuit ceases and the possibility of the battery
discharging is also eliminated.
(a) Relay Terminal 1 (A) Connection Diagram
(b) Relay Terminal 2
(c) Relay Terminal 5
(d) Relay Terminal 3
RY9212166CAM0002US0
5-M18 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(3) Blower Switch
When the blower switch is in the LO, MI, or HI position
(1) Battery (9) Headlight Switch (16) Compressor Magnetic Clutch (A) Fixed Voltage Circuit
(2) Slow-Blow Fuse (80A) (10) Blower Motor Relay (17) Fin Thermistor (Frost Sensor) (B) Servo Motor Drive Circuit
(3) Slow-Blow Fuse (50A) (11) Blower Motor (18) Indicator Lamp (C) CPU
(4) Fuse (5A) (12) Blower Resistor (19) AC Switch (D) Electronic Thermo Amp
(5) Fuse (10A) (13) Blower Switch (Shorting Type) (20) Volume (Temperature Setting)
(6) Fuse (30A) (14) Compressor Clutch Relay (21) Servo Motor
(7) Start Switch (15) Pressure Switch
(8) Power Relay
When the starter switch and the blower switch are turned on, electricity flows from the battery to the coil of the
blower motor relay, turning the blower motor relay on. With the blower motor relay on, the electricity flows to the
blower motor as indicated below.
Lo Position
• Battery → slow-blow fuse (80A) → slow-blow fuse (50A) → fuse (30A) → blower motor relay → blower motor →
blower resistor → ground
Mi Position
• Battery → slow-blow fuse (80A) → slow-blow fuse (50A) → fuse (30A) → blower motor relay → blower motor →
blower resistor → blower switch (E→A) → ground
Hi Position
• Battery → slow-blow fuse (80A) → slow-blow fuse (50A) → fuse (30A) → blower motor relay → blower motor →
blower resistor → blower switch (F→A) → ground
RY9212166CAM0003US0
5-M19 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
2. WIPER
[1] WIPER SWITCH
This switch has four positions, namely (a), (b), (c)
and (d) as indicated in the figure. When the starter key is
in its [RUN] position and the switch is pressed to its (b)
position, the wiper motor operates; pressing it in further
to its (a) position operates the window washer. When the
operator releases the switch, it automatically returns
from position (a) to position (b).
The window washer also operates if it is pressed in
to position (d) on the [OFF] side. When it is released, it
automatically returns in the same way to position (c).
(1) Switch (a) Wash 1 Position
(2) Spring (Both Wiper Motor and
(3) Contact Window Washer Operate)
(4) Switch Body (b) On position (Only the
(5) Movable Contact Wiper Motor Operates)
(6) Insulator (c) Off Position
(d) Wash 2 Position (Only the
Window Washer Operates)
RY9212148CAM0005US0
[2] WIPER
The wiper is composed of a motor, wiper arm, wiper
blade, etc.
The motor is fixed speed and automatically returns to
a set position.
(1) Washer (5) Wiper Blade
(2) Nut (6) Wiper Motor
(3) Wiper Arm (7) Wiper Motor Cover
(4) Nut (8) Flange Nut
RY9212001CAM0028US0
5-M20 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
[3] WIPER MOTOR
A cylindrical ferrite magnet and an armature are
assembled inside the housing of the wiper motor.
A worm gear and a helical gear are attached to the end
of the armature and act as reduction gears and the rod
and a segmented arm provide reciprocating motion,
which is communicated to the wiper arm via the arms
axis.
The motor is a 2-brush specification model and its
rpm cannot be altered.
(1) Segmented Arm (8) Ferrite Magnet
(2) Arm's Axis (9) Helical Gear
(3) Rod (10) Breaker
(4) Worm Gear (11) Motor
(5) Armature Axle (12) Switch
(6) Brush
(7) Armature (A) Wiring Diagram
(Motor Stop Position)
RY9212001CAM0029US0
5-M21 KiSC issued 04, 2021 A
SERVICING
CONTENTS
1. TROUBLESHOOTING.................................................................................................................5-S1
2. MAINTENANCE AND SERVICE RELATED SPECIFICATIONS.................................................5-S4
3. TORQUE .....................................................................................................................................5-S5
4. PRECAUTIONS WHEN REPAIRING THE REFRIGERANT SYSTEM .......................................5-S6
[1] USE OF SERVICE TOOLS ...................................................................................................5-S6
(1) Manifold Gauge Set.........................................................................................................5-S6
(2) Refrigerant Charging Hoses ............................................................................................5-S8
(3) Vacuum Pump Adapter ...................................................................................................5-S9
(4) Electric Gas Leak Tester .................................................................................................5-S9
(5) Canister Tap Valve ..........................................................................................................5-S9
(6) T-Joint............................................................................................................................5-S10
(7) R134a Refrigerant Collection/Recycling Device............................................................5-S10
5. INSPECTING AND CHARGING THE REFRIGERANT SYSTEM .............................................5-S11
[1] CHECKING THE SYSTEM WITH A MANIFOLD GAUGE...................................................5-S11
[2] COLLECTION, VACUUMING AND CHARGING.................................................................5-S15
(1) Collecting Refrigerant ....................................................................................................5-S15
(2) Vacuuming Out the System...........................................................................................5-S15
(3) Charging from the High-Pressure Side..........................................................................5-S17
(4) Charging from the Low-Pressure Side ..........................................................................5-S17
(5) Inspections and Troubleshooting...................................................................................5-S18
6. INSPECTION AND DISASSEMBLY..........................................................................................5-S20
[1] CHECKS AND ADJUSTMENTS .........................................................................................5-S20
(1) Compressor ...................................................................................................................5-S20
(2) Relays............................................................................................................................5-S20
(3) Blower Motor .................................................................................................................5-S22
(4) Blower Resistor .............................................................................................................5-S23
(5) Blower Switch ................................................................................................................5-S24
(6) Servo Motor (for Temp Control).....................................................................................5-S25
(7) Pressure Switch.............................................................................................................5-S26
[2] DISASSEMBLY AND ASSEMBLY ......................................................................................5-S27
(1) Connecting / Disconnecting AC Hoses..........................................................................5-S28
(2) Mounting and Removing the Compressor .....................................................................5-S29
(3) Connecting / Disconnecting Hoses................................................................................5-S32
(4) Removing and Mounting the Receiver ..........................................................................5-S34
(5) Removing and Mounting AC Ducts ...............................................................................5-S35
(6) Removal and Installation of AC Cabin Air Inlets............................................................5-S37
7. CABIN REMOVAL AND MOUNTING ........................................................................................5-S39
[1] REMOVING THE CABIN .....................................................................................................5-S39
8. WINDOW WASHER ..................................................................................................................5-S41
[1] WIPER SWITCH..................................................................................................................5-S41
[2] COMPONENT SCHEMATIC ...............................................................................................5-S42
[3] WIPER MOTOR ..................................................................................................................5-S43
[4] WASHER MOTOR ..............................................................................................................5-S44
9. LIGHTING DEVICES (CAB WORK LIGHT, INTERIOR LIGHT)................................................5-S45
10. REMOVAL AND INSTALLATION OF GLASS ...........................................................................5-S48
[1] PREPARATION ...................................................................................................................5-S48
[2] REMOVING GLASS ............................................................................................................5-S48
[3] INSTALLING GLASS...........................................................................................................5-S49
[4] GLASS TRIM TYPE ............................................................................................................5-S50
KiSC issued 04, 2021 A
[5] HOW TO REPLACE THE GLASS OF THE RIGHT-SIDE WINDOW ..................................5-S50
11. FRONT WINDOW......................................................................................................................5-S53
[1] ADJUSTING THE CLOSING LOCK OF THE FRONT WINDOW (TOP) .............................5-S53
[2] ADJUSTING THE OPEN LOCK OF THE FRONT WINDOW (TOP) ...................................5-S54
KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
1. TROUBLESHOOTING
Compressor
Problem and/or
Possible Cause Solution
Situation
Wearing of or damage to the compressor's
Replace
bearings
Compressor valve damaged Replace
Noise (compressor on)
Belt slipping Adjust or replace
Compressor bracket mounting bolt(s) loose Tighten
Lines vibrating Tighten and/or add clamp(s)
Blower damaged Repair or replace
Noise (compressor off) Magnetic clutch, idler pulley and/or crank pulley
Replace
bearings damaged or wearing
Air Conditioning System
Problem and/or
Possible Cause Solution
Situation
Blown fuse Replace
Main A/C relay defective Replace
Cooling not working
A/C's blower motor damaged Replace
(air not blowing)
A/C's blower switch broken Replace
Wiring harness unplugged or poor contact Fix
Blown fuse Replace
Cooling not working Magnetic clutch broken Repair or replace
(compressor not A/C switch broken Replace
turning) Pressure switch broken Replace
Belt slipping Adjust or replace
Not enough refrigerant Check with a manifold gauge
Cooling not working
Expansion valve broken Replace
(other)
Compressor broken Replace
Filter clogged Clean or replace
Cooling not working Clean or replace the temperature
effectively Frost on the evaporator
switch
(not enough air
blowing) A/C's blower motor damaged Replace
A/C blower resistor broken Replace
Not cooling effectively Not enough refrigerant Check with a manifold gauge
(lots of foam visible in Refrigerant gas leaking from the cooling circuit Repair and/or recharge refrigerant
sight glass) Air got in Check with a manifold gauge
Too much refrigerant
Refrigerant overcharged Check with a manifold gauge
(no foam in sight glass)
Not cooling effectively Belt slipping Adjust or replace
(compressor not Magnetic clutch broken Repair or replace
rotating properly) Compressor broken Replace
5-S1 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Problem and/or
Possible Cause Solution
Situation
Thermistor broken Replace
Not cooling effectively Hot water valve damaged Replace
(other) Condenser clogged with dirt or debris Clean
Expansion valve broken Replace
Hot water valve damaged Replace
Not heating effectively
Servo motor broken Check and repair
Blower fan switch broken Check and repair
Not enough air flow A/C main relay broken Replace
(blower motor not Brushes have poor contact Replace
turning) Blown fuse Replace
Miswiring or poor connections Check and repair
Not enough air flow Blower resistor damaged Replace
(air flow does not Relay damaged Replace
change to speed 3) Blower fan switch broken Replace
Blower not tight enough Check and repair
Blower deformed Replace
Blower hitting its casing Check and repair
Not enough air flow
Something blocking the inlet Check and repair
(other)
Frost on the evaporator Clean or replace
Filter clogged Clean or replace
Vent ducts clogged or detached Check and repair
Battery voltage too low Charge the battery
Rotor is hitting the stator Replace
Not cooling effectively Miswiring or loose connectors Check and repair
(compressor clutch not Relay damaged Replace
working) Coil shorted Replace
Ground defective Check and repair
Coil burned out Replace
Not cooling effectively Refrigerant overcharged Check with a manifold gauge
(high-pressure level Condenser clogged with dirt or debris Clean
too high) Air got in Check with a manifold gauge
Not enough refrigerant Check with a manifold gauge
Not cooling effectively Compressor discharge valve damaged Replace
(high-pressure level Compressor gasket damaged Replace
too low)
Error in the low-pressure line
Replace
(cracked or clogged)
Not cooling effectively Refrigerant overcharged Check with a manifold gauge
(low-pressure level too
high) Expansion valve too far open Replace
5-S2 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Problem and/or
Possible Cause Solution
Situation
Not enough refrigerant Check with a manifold gauge
Not cooling effectively Frost on the evaporator Clean or replace
(low-pressure level too Error in the low-pressure line
low) Replace
(cracked or clogged)
Expansion valve clogged Replace
Not cooling effectively
(both low and high
Refrigerant overcharged Check with a manifold gauge
pressure levels too
high)
Not cooling effectively
(both low and high
Not enough refrigerant Check with a manifold gauge
pressure levels too
low)
Cannot control Servo motor broken Replace
temperature Temperature control dial broken Replace
(servo motor and/or
temperature control Controller of the wire harness is off Repair or replace
dial defective)
Cannot control the Servo motor broken Replace
temperature
(hot water valve does Hot water valve damaged Replace
not open normally)
Cannot control the Heater hose is pinched Fix
temperature
(poor heater hose Heater hose is bent or broken Repair or replace
layout)
Water leak (water leak Drain hose bent or broken Check and repair
inside the cab) Drain hose clogged Clean
Wiper
Problem and/or
Possible Cause Solution
Situation
Fuse blown (a part inside the wiper motor or Pinpoint the cause of the damage
some other moving part is shorted or burned out) and replace
Wiper motor faulty (damaged armature, worn
Replace
motor brushes, motor shaft locked)
Wiper doesn't work
Wiper switch faulty Replace
Faulty operation of linkage mechanism due to
Fix
foreign matter
Wiper arm locked or rusted together Grease up or replace
Wiper motor faulty (damaged armature, poor
contact due to worn motor brushes, faulty Replace
operation of motor shaft)
Wiper moves too
slowly Battery voltage low Recharge or replace
Wiper arm shaft rusty, foreign matter stuck in it Grease up or replace
Poor contact in wiper switch Replace
Wiper motor faulty
Wiper fails to stop in
(Dirty or poor contact of the contacts at the Replace
the correct position
auto-stop position due to foreign matter)
RY9212001CAS0001US0
5-S3 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
2. MAINTENANCE AND
SERVICE RELATED SPECIFICATIONS
Allowable Limit
Item Factory specification
Value
0.30 to 0.65 mm
AC Compressor Magnetic Clutch Air Gap –
0.0118 to 0.0255 in.
Electrical
Magnetic Clutch Stator Coil 3.0 to 4.0 Ω –
Resistance
0.15 to 0.20 MPa
Pressure
1.5 to 2.0 kgf/cm2 –
(low-pressure side)
Cooling Cycle 21 to 28 psi
(cooling cycle when operating normally) Pressure 1.27 to 1.66 MPa
(high-pressure 13 to 17 kgf/cm2 –
side) 185 to 242 psi
Lower than the values
below
Pressure setting
About 0.196 MPa –
(low-pressure side)
2.0 kgf/cm2
Pressure switch 28.4 psi
(dual type) (when pressure switch is off) Higher than the values
Pressure setting below
(high-pressure About 3.14 MPa –
side) 32 kgf/cm2
455 psi
Deflects 12 to 15 mm
(0.47 to 0.59 in.) when
AC drive belt Tension –
68.6 N (7 kgf, 15.4 lbf) of
forced is applied
R134a
Type
Refrigerant 0.65 to 0.75 kg –
(recharge volume)
1.43 to 1.65 lbs
ND-OIL8 <PAG*oil>
Type 100 to 120 cc
Compressor Oil –
(usage volume) 0.106 to 0.127 U.S.qts
0.088 to 0.106 Imp.qts
*PAG : Polyalkylene glycol (synthetic oil)
RY9212001CAS0002US0
5-S4 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
3. TORQUE
The following table indicates the specified tightening torque for nuts.
Items N·m kgf·m lbf·ft
Condenser mounting M8 nut 17.7 to 20.6 1.8 to 2.1 13.0 to 15.2
Compressor mounting M8 bolt 16.7 to 19.6 1.7 to 2.0 12.3 to 14.5
Compressor bracket M12 bolt 77.5 to 90.2 7.9 to 9.2 57.1 to 66.5
mounting M8 bolt 16.7 to 19.6 1.7 to 2.0 12.3 to 14.5
Receiver mounting M8 bolt 17.7 to 20.6 1.8 to 2.1 13.0 to 15.2
High pressure line 1 M6 bolt 7.8 to 11.8 0.8 to 1.2 5.8 to 8.7
mounting
(on condenser side) M22 × 1.5 lock nut 19.6 to 24.5 2.0 to 2.5 14.5 to 18.1
Between condenser and M6 bolt 3.9 to 6.9 0.4 to 0.7 2.9 to 5.1
receiver M16 × 1.5 lock nut 11.8 to 14.7 1.2 to 1.5 8.7 to 10.8
High pressure line 2
mounting M16 × 1.5 lock nut 11.8 to 14.7 1.2 to 1.5 8.7 to 10.8
(on receiver side)
Low-pressure line M6 bolt 7.8 to 11.8 0.8 to 1.2 5.8 to 8.7
between A/C and
compressor M24 × 1.5 lock nut 29.4 to 34.3 3.0 to 3.5 21.7 to 25.3
M6 bolt 3.9 to 6.9 0.4 to 0.7 2.9 to 5.1
A/C mounting
M8 bolt 9.8 to 15.7 1.0 to 1.6 7.2 to 11.6
Magnetic clutch mounting M6 bolt 10.8 to 16.2 1.10 to 1.65 8.0 to 11.9
RY9212148CAS0002US0
5-S5 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
4. PRECAUTIONS WHEN REPAIRING
THE REFRIGERANT SYSTEM
[1] USE OF SERVICE TOOLS
(1) Manifold Gauge Set
Always follow the warnings and regulations below when inspecting or repairing the air conditioning system.
It is also extremely important that no one other than specially trained service personnel handles refrigerants.
CAUTION
• If the liquid refrigerant comes in contact with skin, it results in frostbite, so always be careful when
handling refrigerants. Always wear goggles when working on this system in order to protect your eyes.
• Refrigerant service containers are made very sturdy for safety. However, they can explode if handled
improperly. Always follow the instructions printed on their labels. In particular, never heat a refrigerant
container above 40 °C (104 °F). Also, never drop one from any height.
• Do not steam clean this system. In particular, this system is under extremely high pressure, so do not
steam clean the condenser as it may cause the system to explode.
• If an error is made in handling the service valve or in connecting a hose between the compressor's
service valve and a manifold gauge, it may cause the refrigerant service container or the charging hose
to explode. When connecting hoses or handling service valves, always check the pressure on the
high-pressure side or on the low-pressure side.
• When recharging refrigerant with the compressor operating, do not open the high-pressure valve of the
manifold gauge.
• Be careful of gas toxicity. The refrigerant gas in its natural state is harmless and is not toxic. However,
when it comes in contact with very hot parts, it can break down chemically, producing hazardous
materials.
• Do not heat service canisters unless absolutely necessary. When necessary to heat a canister, use water
at or below 40 °C (104 °F). Never use boiling water to heat a canister.
• Take care with the following points on storing and handling service canisters.
• Store in a cool, dry place.
• Never drop or strike a canister.
• Do not use service canisters that are deformed, have unusable screws or are otherwise damaged.
• Never heat a service canister unless necessary. If one must be heated for some reason, use water at
or below 40 °C (In such cases, never warm the canister while heating up the water). Do not immerse
the valve of the service canister in water. Do not turn the service canister upside down. Turning it
upside down allows liquid refrigerant into the compressor, which damages the valve.
• Do not shake hard (If the mounting of the valve is not secure, it may come off).
• Use ND-OIL8 (made by DENSO (Co. Ltd.)) compressor oil (ND-OIL6 is designated for use with R12, so
do not mistakenly use ND-OIL6).
• Precautions on Inspecting and Charging A/C Gas
• Perform all work in a well-ventilated location.
• Be careful when handling high-pressure valves. When recharging refrigerant with the engine running,
do not open the high-pressure valve (HI) of the manifold gauge. Overcharging refrigerant may cause
problems such as poor cooling and overheating.
IMPORTANT
• Using R12 refrigerant in an R134a A/C system may cause problems to result, such as leaks of refrigerant
at O-rings and fogging of the sight glass. Consequently, the shapes of line joints, service valves and
service tools are different in order to prevent mistakes in connecting or recharging the wrong system.
• Always keep the work area clean, dry and free of any dirt or dust. Always wipe off any water from line
fittings with a clean cloth before opening the fitting.
• Only use R134a refrigerant service tools.
• When discharging refrigerant, use an R134a refrigerant collection/recycling machine.
• Prior to connecting a charging hose to the tap valve of a refrigerant canister, check each seal and make
sure it is not clogged up.
• When disconnecting charging hoses from compressor and receiver valves, do so as quickly as possible
to minimize the leakage of gas.
• Be careful to only charge with the specified amount of refrigerant; never overcharge the system.
This is important because overcharging the refrigerant can cause poor cooling performance among other
things.
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• Hand tighten when connecting the charging hose to the canister's tap valve. Do not use pliers to tighten
the charging hose.
• Store refrigerant containers in a cool, dark place and never leave them in direct sunlight or in a hot place.
• R134a compressor oil readily absorbs moisture, so always seal any parts after disconnecting them.
• Do not use any of the old style R12 refrigerant or previous kinds of refrigerant compressor oil.
RY9212079CAS0001US0
The manifold gauge set has a valve handle for opening and
closing valves. The valve handle marked LO is for use on the
low-pressure valve (5) and the valve handle marked HI is for use on
the high-pressure valve (3). The following circuits can be achieved
by variously opening and closing the high and low pressure valves.
(1) Low-Pressure Gauge (4) Valve Core
(2) High-Pressure Gauge (5) Low-Pressure Valve
(3) High-Pressure Valve
RY9212001CAS0005US0
When low and high pressure valves are closed
The following 2 circuits are formed.
Port (C) → Low-pressure gauge (1)
Port (A) → High-pressure gauge (2)
CAUTION
• Be sure to open the valve core (d).
(1) Low-Pressure Gauge (2) High-Pressure Gauge
RY9212001CAS0006US0
With the low-pressure valve open and the high-pressure valve
closed
The following circuits are formed.
Port (C) → Low-pressure gauge (1)
Port (C) → Port (B)
Port (C) → Port (D)
Port (A) → High-pressure gauge (2)
CAUTION
• Be sure to open the valve core (D).
(1) Low-Pressure Gauge (2) High-Pressure Gauge
RY9212001CAS0007US0
With the low-pressure valve closed and the high-pressure
valve open
The following circuits are formed.
Port (C) → Low-pressure gauge (1)
Port (A) → Port (B)
Port (A) → Port (D) (Be sure to open the valve core).
Port (A) → High-pressure gauge (2)
CAUTION
• Be sure to open the valve core (D).
(1) Low-Pressure Gauge (2) High-Pressure Gauge
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With low and high pressure valves open
The following circuits are formed.
Port (A) → High-pressure gauge (2)
Port (A) → Low-pressure gauge (1)
Port (A) → Port (B)
Port (A) → Port (C)
Port (A) → Port (D) (Be sure to open the valve core).
CAUTION
• Be sure to open the valve core (D).
(1) Low-Pressure Gauge (2) High-Pressure Gauge
RY9212001CAS0009US0
(2) Refrigerant Charging Hoses
The three kinds of refrigerant charging hoses are
distinguishable by color. Each of the refrigerant charging hoses is to
be used as follows.
• In line with the A/C manufacturer's recommendation, the blue
hose (6) is to be used on the low-pressure side (intake side), the
green hose (5) on the cooling side (center connection port) and
the red hose (3) on the high-pressure side (discharge side).
(When connecting)
• Press the quick-disconnect adapter (4) into the recharge valve
and press part A in until you hear it catch.
CAUTION
• While pressing in to make a connection, be careful not to
bend any lines.
• When connecting a quick-disconnect adapter, if you move
the sleeve (7) before the quick-link connector is connected
to the charge valve, move the sleeve back to its original
position and then try making the connection again.
• If there is any refrigerant left in the refrigerant charging
hose, it can be difficult to connect the quick-link connector.
In this case, make the connection after relieving the
pressure remaining in the refrigerant charging hose.
(Pressing on the pusher (8) eliminates any remaining
pressure.)
(When disconnecting)
• With part A of the quick-disconnect adaptor held in place, slide
part B up.
CAUTION
• After removing the quick-disconnect adaptor, be sure to
put a cap on the service valve of the adaptor.
(1) Low-Pressure Valve (7) Sleeve
(2) High-Pressure Valve (8) Pusher
(3) Red Hose (9) Sleeve
(4) Quick-Disconnect Adapter
(5) Green Hose a : Makes a Catching Sound
(6) Blue Hose
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(3) Vacuum Pump Adapter
Purpose of the Vacuum Pump Adapter
1. After the A/C cooling system is vacuumed, when the vacuum
pump is stopped, there is a vacuum inside the hoses of the
manifold gauge, so the oil of the vacuum pump flows back into
the refrigerant charging hose. If the refrigerant system is
charged in this state, the vacuum pump oil remaining in the
refrigerant charging hose will go into the A/C refrigerant system
along with the refrigerant. A vacuum pump adaptor equipped
with a solenoid valve is used to prevent this backflow of oil from
the vacuum pump. The role of the solenoid valve is to close
when electricity is flowing to the solenoid valve, cutting it off
from outside air and maintaining the vacuum; when the
electricity is cut off, the valve opens, bringing in outside air and
relieving the vacuum.
2. If this adapter is connected to the currently used R12 vacuum
pump, it enables the vacuum pump to be used for both R134a
and R12.
(1) Vacuum Pump Adapter (5) Air
(2) Vacuum Pump (6) For R12
(3) For R134a (7) Plug Cap
(4) Solenoid Valve
RY9212001CAS0011US0
(4) Electric Gas Leak Tester
The old style R12 gas leak tester are not sensitive enough for
R134a and cannot be used. Consequently a new and very sensitive
electrical gas leak tester has been designed that can be used with
both R134a and R12.
[NOTE]
Halogenated Torch Gas Leak Testers
• Because this tester detects gas leaks based on the reaction of
chlorine in the refrigerant, it cannot detect R134a because it
does not contain chlorine.
(1) Electrical Gas Leak Tester
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(5) Canister Tap Valve
The canister tap valve used in recharging the refrigerant of the
A/C system has to be used as follows.
1. Before attaching the canister tap valve to the refrigerant
container, rotate the handle (1) counterclockwise until the
needle of the valve is completely retracted.
2. Rotate the plate nut (disk) (3) counterclockwise to its highest
position and then screw the canister tap valve into the sealed
tap.
3. Rotate the plate nut clockwise as far as you can and fasten the
center charging hose to the canister tap valve.
4. Tighten the plate nut securely by hand.
5. Rotate the handle (1) clockwise to open a hole in the sealed tap.
6. To charge the system with refrigerant, turn the handle (1)
counterclockwise. To stop charging, turn the handle clockwise.
(1) Butterfly Handle (3) Disc
(2) Connector (4) Needle
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(6) T-Joint
A T-joint (2) is used when using two refrigerant canisters (4) at
the same time to make gas recharging more efficient.
1. Attach a refrigerant canister service valve on each side of the
T-joint (2) and connect a refrigerant charging hose (1) to the
T-joint.
(1) Refrigerant Charging Hose (Green) (3) Canister Tap Valve
(2) T-Joint (4) Refrigerant Canister
RY9212001CAS0014US0
(7) R134a Refrigerant Collection/Recycling Device
When it is necessary to discharge the refrigerant in order to
work on the machine, a collection / recycling device must be used
(Never release refrigerant into the atmosphere).
IMPORTANT
• Use a dedicated R134a refrigerant collection/recycling
device.
• To prevent any damage to the compressor, use neither R12
system refrigerant nor cooling system oil in R134a
equipment.
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5. INSPECTING AND CHARGING THE REFRIGERANT
SYSTEM
[1] CHECKING THE SYSTEM WITH A MANIFOLD GAUGE
IMPORTANT
• Be aware that the gauge pressure values noted in the following test are measured under identical
conditions and they may vary somewhat from your gauge pressure values, depending on the prevailing
conditions.
Conditions
• Ambient temperature : 30 to 35 °C (86 to 95 °F)
• Engine RPM : Approx. 1500
• Temperature control lever : Max cooling position
• Blower switch : HI Position
RY9212001CAS0016US0
Manifold connections and test preparations
1. Close the manifold gauge's high (3) and low (4) pressure valves
tightly.
2. Connect the red (2) refrigerant charging hose to the
high-pressure charge valve (7) and the blue or yellow (1)
refrigerant charging hose to the low-pressure charge valve (6).
CAUTION
• Use the refrigerant pressure in the refrigerant cycle to
completely flush out the air in the refrigerant charging hose
from the end of the manifold gauge's connection.
3. Start up the engine and set it at approximately 1,500 rpms.
4. Turn the AC switch on and set the temperature control dial to the
max cooling position.
5. Set the blower switch to its HI position.
(1) Refrigerant Charging Hose (5) Manifold Gauge
(Blue or Yellow) (6) Low-Pressure Side Charge Valve
(2) Refrigerant Charging Hose (Red) (7) High-Pressure Side Charge Valve
(3) High-Pressure Valve
(4) Low-Pressure Valve
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When operating normally
If the refrigerant cycle is operating normally, readings will be
around the factory specifications in the table below.
Low 0.15 to 0.20 MPa
pressure 1.5 to 2.0 kgf/cm2
Factory side 21 to 28 psi
Gas Pressure specifica-
tion High 1.27 to 1.66 MPa
pressure 13 to 17 kgf/cm2
side 185 to 242 psi
(1) Low Pressure Side (2) High Pressure Side
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Without enough refrigerant
1. Symptoms that appear in the refrigerant cycle
• Both high (2) and low (1) side pressures are too low.
Low-pressure side (1) : 0.05 to 0.10 MPa (0.5 to 1.0 kgf/cm2,
7.1 to 14.2 psi)
High-pressure side (2) : 0.69 to 0.98 MPa (7 to 10 kgf/cm2,
99.6 to 142.2 psi)
• Foam visible in the sight glass.
• Air output by the A/C appears to be cooled.
2. Possible Cause
• Gas leaking from the circuit of the refrigerant cycle.
3. Solution Methods
• Use an electric gas leak tester to check for leaks and repair
any found.
• Recharge the system with an appropriate amount of
refrigerant.
(1) Low Pressure Side (2) High Pressure Side
RY9212001CAS0019US0
Excess refrigerant or insufficient condenser cooling
1. Symptoms that appear in the refrigerant cycle
• Both high (2) and low (1) side pressures are too high.
Low-pressure side (1) : 0.20 to 0.35 MPa (2.0 to 3.5 kgf/cm2,
28.4 to 49.8 psi)
High-pressure side (2) : 1.96 to 2.45 MPa (20 to 25 kgf/cm2,
284.5 to 355.6 psi)
2. Possible Causes
• Cycle charged with too much refrigerant.
• Poor condenser cooling.
3. Solution Methods
• Clean the condenser.
• Adjust the tension of the A/C drive belt to the appropriate
tension.
• If the 2nd item above is normal, check the amount of
refrigerant.
CAUTION
• To discharge excess refrigerant, loosen the manifold's
gauge's low-pressure valve and slow discharge it.
(1) Low Pressure Side (2) High Pressure Side
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Air mixed into the cycle
1. Symptoms that appear in the refrigerant cycle
• Both high (2) and low (1) side pressures are too high.
Low-pressure side (1) : 0.20 to 0.35 MPa (2.0 to 3.5 kgf/cm2,
28.4 to 49.8 psi)
High-pressure side (2) : 1.96 to 2.45 MPa (20 to 25 kgf/cm2,
284.5 to 355.6 psi)
• The line on the low-pressure side (1) feels cold to the touch.
2. Possible Causes
• Air is mixed in the refrigerant cycle
3. Solution Methods
• Replace the receiver.
• Check the amount of compressor oil and whether it is
contaminated.
• Vacuum it out and charge the cycle again with fresh
refrigerant.
CAUTION
• If you fail to vacuum out a refrigerant cycle like that
mentioned above and simply charge the cycle with
refrigerant, the problem may recur.
(1) Low Pressure Side (2) High Pressure Side
RY9212001CAS0021US0
Moisture mixed into the cycle
1. Symptoms that appear in the refrigerant cycle
• At first the A/C works normally, but after some time, the
pressure on the low-pressure side (1) becomes a vacuum
and the high-pressure side (2) is at a low pressure.
Low-pressure side (1) : Vacuum;
High-pressure side (2) : 0.69 to 0.98 MPa (7 to 10 kgf/cm2,
99.6 to 142.2 psi)
2. Possible Causes
• Moisture in the refrigerant cycle freezes up in the expansion
valve orifice, creating a temporary blockage. As time
elapses, the ice thaws and it returns to normal.
3. Solution Methods
• Replace the receiver.
• Eliminate the moisture in the refrigerant cycle by repeatedly
vacuuming it out.
• Recharge the system with an appropriate amount of
refrigerant.
(1) Low Pressure Side (2) High Pressure Side
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Refrigerant fails to circulate
1. Symptoms that appear in the refrigerant cycle
• Low-pressure side (1) becomes a vacuum and the
high-pressure side (2) is at low pressure.
Low-pressure side (1) : Vacuum;
High-pressure side (2) : 0.49 to 0.59 MPa (5 to 6 kgf/cm2,
71.2 to 85.3 psi)
2. Possible Causes
• The line above the expansion valve orifice is frozen up and
the refrigerant cannot flow due to moisture and/or dirt stuck
in the refrigerant cycle.
3. Solution Methods
Wait for some time to elapse and determine whether it is dirt or
moisture blocking the line by whether A/C operation recovers or
not.
• If the problem is moisture, the problem resolves itself, as
indicated in the previous section.
• If the cause is dirt, remove the expansion valve and blow out
any dirt with compressed air.
• If the dirt cannot be eliminated, replace the expansion valve
and the receiver. Vacuum out the line and charge the cycle
with an appropriate amount of fresh refrigerant.
• If the problem is caused by a gas leak in the heat-sensitive
tube, replace the expansion valve.
(1) Low Pressure Side (2) High Pressure Side
RY9212001CAS0023US0
Expansion valve too far open
1. Symptoms that appear in the refrigerant cycle
• Both high (2) and low (1) side pressures are too high.
Low-pressure side (1) : 0.29 to 0.39 MPa (3 to 4 kgf/cm2,
42.7 to 56.9 psi)
High-pressure side (2) : 1.96 to 2.45 MPa (20 to 25 kgf/cm2,
284.5 to 355.6 psi)
• Either frost or heavy condensation on the low-pressure side
line
2. Possible Causes
• Problem with the expansion valve.
• The flow volume adjustment is set improperly.
3. Solution Methods
• Replace the expansion valve.
(1) Low Pressure Side (2) High Pressure Side
RY9212001CAS0024US0
Faulty compression from compressor
1. Symptoms that appear in the refrigerant cycle
• Low-pressure side (1) : 0.39 to 0.59 MPa (4 to 6 kgf/cm2,
56.9 to 85.3 psi)
High-pressure side (2) : 0.69 to 0.98 MPa (7 to 10 kgf/cm2,
99.6 to 142.2 psi)
2. Possible Causes
• Compressor is leaking.
3. Solution Methods
• Replace the compressor.
CAUTION
• When the compressor is producing a faulty compression, it
can be detected with a manifold gauge (figure at left).
(1) Low Pressure Side (2) High Pressure Side
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[2] COLLECTION, VACUUMING AND CHARGING
IMPORTANT
• Follow 4. Precautions when Repairing the Refrigerant Cycle when discharging, vacuuming and charging
the refrigerant system.
RY9212001CAS0026US0
(1) Collecting Refrigerant
Get a R134a refrigerant collection/recycling device ready to
use.
1. Connect the low-pressure hose (blue) from the refrigerant
collection/recycling machine to the low-pressure side charge
valve. Connect the high-pressure hose (red) to the
high-pressure charge valve.
2. Follow the instructions of the manufacturer and discharge the
refrigerant from the cooling system.
IMPORTANT
• Do not use device except an R134a refrigerant collection
and recycling machine. In order to prevent damage to the
compressor, do not mix R134a equipment, refrigerant or
compressor oil into an R12 system.
CAUTION
• When removing the charge valve hose, cover it with a rag
to protect your fingers and eyes from frost bite from the
refrigerant.
(1) Refrigerant Charging Hose (5) Manifold Gauge
(Blue or Yellow) (6) Low-Pressure Side Charge Valve
(2) Refrigerant Charging Hose (Red) (L Mark)
(3) High-Pressure Valve (7) High-Pressure Side Charge Valve
(4) Low-Pressure Valve (H Mark)
RY9212166CAS0002US0
(2) Vacuuming Out the System
No. Description of Work Remarks
(1) Check the connected parts and correct any problems
(2) Start vacuuming Approx 15 minutes, 750 mmHg (229 in.Hg) or greater
(3) Stop vacuuming Leave for five minutes
(4) Check the concentration If the gauge indicates abnormally, return to (1)
(5) Charge with refrigerant 98 kPa (1.0 kgf/cm2, 14 psi)
(6) Check for gas leaks
(7) Charge with refrigerant
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Manifold gauge connections and vacuuming
1. Close the high-pressure (HI) and low-pressure (LO) valves of
the manifold gauge.
2. Connect the L-shaped side of 2 charging hoses to quick joints
and connect them to the compressor and receiver service
valves.
Blue hose Low-pressure side (L mark)
Red hose High-pressure side (H mark)
3. Connect the charging hose (green) in the middle of the manifold
gauge to the vacuum pump.
4. Open the high and low pressure valves of the manifold gauge.
5. Turn the vacuum pump switch on and vacuum the line until the
low-pressure gauge reaches a reading of approximately
–0.1 MPa (–750 mmHg). (about 15 minutes)
6. Once about –0.1 MPa (–750 mmHg) is reached, close the high
and low pressure valves of the manifold gauge and stop the
vacuum pump.
7. Let it set for at least five minutes and check to make sure the
indicator needle of the low-pressure gauge does not approach
0.
8. If the needle of the gauge approaches 0, the system's
airtightness is compromised somewhere, so after inspecting
and repairing the line connections, run the vacuum again and
check to make sure there are not any places that are not airtight.
(1) Vacuum Pump (A) Inspection Line Connections
(2) High-Pressure Valve (B) Low-Pressure Gauge
(3) Low-Pressure Valve
(4) High-Pressure Side (H Mark) (a) Valve Settings
(5) Low-Pressure Side (L Mark) (L: Closed, H: Closed)
(b) Leave for at Least Five Minutes
(c) If the Needle Approaches 0,
Inspecting and Repairing the Line
Connections.
RY9212001CAS0029US0
Connections with a refrigerant collector or service canister
1. Close the high-pressure (HI) and low-pressure (LO) valves of
the manifold gauge.
2. Connect the charging hose (green) connected to the vacuum
pump to the collector or service canister (Air is in the charging
hose, so do not open the high or low pressure valves).
3. Discharge from the collector or open the service canister's
valve.
4. Press on the valve core of the manifold gauge for three to five
seconds to discharge any air from the hose.
(1) Service Canister Valve (a) Press Valve Core to Expel Air
(2) High-Pressure Valve
(3) Low-Pressure Valve
(4) High-Pressure Side (H Mark)
(5) Low-Pressure Side (L Mark)
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(3) Charging from the High-Pressure Side
Charging from the High-pressure Side
CAUTION
• Important : do not start the engine. If the engine is running,
the gas will flow back and burst either the service canister
or a hose.
IMPORTANT
• Do not open the low-pressure valve of the manifold gauge.
• If the service canister has been changed, be sure to expel
any air out of the charging hose (green).
1. Without starting the engine, open the high-pressure valve and
charge with approx 500 g of gas.
2. While charging, once the low-pressure gauge indicates approx
0.10 MPa (approx 1.0 kgf/cm2), close the high-pressure valve
and the service canister valve for the time being.
3. Use a gas detector to check the hoses and pipe connections for
gas leaks; if any exist, repair them. If there are no leaks,
continue charging the refrigerant.
4. When charging on the high-pressure side stops, close the
high-pressure valve on the manifold gauge and the service
canister valve, and then charge from the low-pressure side.
(1) Service Canister Valve (a) Press Valve Core to Expel Air
(2) High-Pressure Valve
(3) Low-Pressure Valve
RY9212001CAS0031US0
(4) Charging from the Low-Pressure Side
Charging from the Low-Pressure Side
CAUTION
• Never open the manifold gauge's high-pressure valve when
charging refrigerant while the engine is running (If the
high-pressure valve is opened, high-pressure gas will flow
back up the line and rupture the service canister or a
charging hose).
• Always keep the service canister upright when charging.
IMPORTANT
• If the service canister has been changed, be sure to expel
any air out of the charging hose (green).
1. Check and make sure the manifold gauge's high-pressure valve
is closed.
2. After starting the engine, set it to approx 1500 rpms and open
all of the doors.
3. Turn the A/C switch on and set the temperature control to
maximum cooling.
4. Open the manifold gauge's low-pressure valve and the service
canister valve and charge with the specified amount of gas.
5. After completing refrigerant charging, close the manifold
gauge's low-pressure valve and the service canister valve and
stop the engine.
6. Check for any gas leaks with the gas leak tester.
(1) Service Canister Valve (a) Press Valve Core to Expel Air
(2) High-Pressure Valve
(3) Low-Pressure Valve
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(5) Inspections and Troubleshooting
[A] Checking the Quantity of AC Gas
Checking with a manifold gauge
All the manifold gauge values indicated below are
measurements taken under the specified conditions. Please note
that the measurements you take will vary depending on the
prevailing conditions.
Conditions
Doors All open
Inside/outside air switch Inside
Ambient air temperature 30 to 35 °C (86 to 95 °F)
Engine RPM About 1,500
Temperature control Max cooling position
Blower switch HI
1. After closing both the high and low-pressure valves of the
manifold gauge, connect charging hoses (red/blue) to the
compressor and the service canister valve of the receiver tank.
2. Loosen the low-pressure valve slightly to expel any air from the
charging hose. After expelling the air, close the low-pressure
valve again.
3. Expel air from the charging hose on the high-pressure side in
the same way.
4. Start the engine and set it at approximately 1500 rpms.
5. Turn the A/C switch ON and set the temperature control to
maximum cooling and the blower switch to HI.
6. Read the values on the low-pressure and high-pressure
gauges.
Factory Low 0.15 to 0.20 MPa
specifica- pressure 1.5 to 2.0 kgf/cm2
tion side 21 to 28 psi
When Normal
Factory High 1.27 to 1.66 MPa
specifica- pressure 13 to 17 kgf/cm2
tion side 185 to 242 psi
(1) High-Pressure Gauge (a) High-Pressure Side
(2) Low-Pressure Gauge (Compressor's H-Mark Side)
(3) High-Pressure Valve (b) Low-Pressure Side
(4) Low-Pressure Valve (Compressor's L-Mark Side)
(5) Valve Core
(6) Red
(7) Blue
(8) Quick Joint
(9) Green
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Checking with the sight glass
Conditions
Doors All open
Inside/outside air switch Inside
Ambient air temperature 30 to 35 °C (86 to 95 °F)
Engine RPM About 1500 rpm
Temperature control Max cooling position
Blower switch HI
Criteria
No air bubbles at all in the flow. In this case, both high
(a) Overcharged and low-pressure sides are at high pressure and the
cooling is ineffective.
Almost no air bubbles in the flow. If the engine rpm is
Normal
(b) raised gradually from idle to 1500 rpm, the air bubbles
amount
disappear and the flow becomes transparent.
(c) Undercharged Air bubbles flow past constantly.
(1) Sight Glass
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6. INSPECTION AND DISASSEMBLY
[1] CHECKS AND ADJUSTMENTS
(1) Compressor
Magnetic clutch
1. Start the engine.
2. With the AC switch on the AC control panel off, check and make
sure that no scraping sounds or other noise comes from the
pulley as it turns.
3. Turn the AC switch and the fan switch on to make the AC
system operate. With the AC working, check and make sure the
magnetic clutch is not slipping.
4. If there is any noise, repair or replace it.
(1) Magnetic Clutch
RY9212001CAS0035US0
Stator coil
1. Remove the magnetic clutch's 1P connector.
2. Measure the resistance between the 1P connector on the
magnetic clutch side and the body of the stator.
3. If the measurement falls outside of the factory specification,
replace the stator coil.
Between stator body and
harness side of stator Factory specification 3 to 5 Ω
coil
RY9212148CAS0009US0
(2) Relays
After turning the starter switch off, remove the cover under the
seat, remove each relay and take the following measurements.
(1) Fuse Box (A) Blower Motor Relay
(B) Compressor Clutch Relay
(C) Power Relay
(D) Cab Work Light Relay
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5-S20 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Harness-side checks
Between battery and power relay
1. Measure the voltage between terminal 3 in the fuse box and
ground on the body.
2. Set the starter switch to [RUN].
3. Measure the voltage between terminals 1 and 2 in the fuse box.
4. If the voltages of each are the same as the battery voltage
(DC 11 to 14V), they are normal.
Testing individual relays
1. Impress the battery voltage between terminals 1 and 2 of the
relay.
2. Check for continuity between terminals 3 and 4 of the relay.
3. If there is continuity between the terminals, it is normal.
(a) Terminal 1 (A) Fuse Box Terminals
(b) Terminal 2 (B) Individual Relay
(c) Terminal 4
(d) Terminal 3
RY9212166CAS0004US0
Harness-side checks
Between battery and blower motor relay
1. Measure the voltage between terminal 1in the fuse box and
ground on the body.
2. If the voltage is the same as the battery voltage (DC 11 to 14V),
it is normal.
Between battery and cab work light relay
1. Measure the voltage between terminal 1in the fuse box and
ground on the body.
2. If the voltage is the same as the battery voltage (DC 11 to 14V),
it is normal.
Testing individual relays
1. Impress the battery voltage between terminals 3 and 5 of the
relay.
2. Check for continuity between terminals 1 and 2 of the relay.
3. If there is continuity between the terminals, it is normal.
(a) Terminal 5 (A) Fuse Box Terminals
(b) Terminal 3 (B) Individual Relay
(c) Terminal 2
(d) Terminal 1
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5-S21 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(3) Blower Motor
Checking the Voltage
1. Remove the blower motor connector.
2. After starting the engine, set the fan switch on [3].
Measure the voltage based on the table below.
Mea-
sure-
Connector Name Connector Name
ment Pin No. Pin No.
(+terminal side) (- terminal side)
Point
s
Blower motor
(a) <1> Body GND –
connector
Normal: 12 V
Irregular: Large discrepancy from 12 V
(1) Blower Motor Connector (2) Fan Switch
RY9212148CAS0014US0
Blower motor test
1. Remove the blower resistor.
2. Turn the blower motor by hand and check whether it turns
smoothly.
3. If the blower motor fails to turn, check the motor.
(1) Blower Motor (A) Circuit Diagram
(a) (+) Terminal
(b) (–) Terminal
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5-S22 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(4) Blower Resistor
1. Remove the blower resistor's 3P connector.
2. Measure the resistance between terminals 2 and 3 and between
2 and 1 of the connector on the AC unit side.
3. If they differ from the factory specifications, the blower resistor
is faulty.
Terminal 3 – terminal 2 About 1.7 Ω
Factory specification
Terminal 1 – terminal 2 About 0.7 Ω
(1) 3P Connector (2) 3P Connector (AC Unit Side)
RY9212166CAS0005US0
(a) Fuse (221 ± 10 °C, 430 ± 18 °F) <1> R1 Terminal
(A) 3P Connector (AC Unit Side) <2> E Terminal
<3> R2 Terminal
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5-S23 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(5) Blower Switch
Voltage check
1. Disconnect the blower switch connector.
2. Turn the key switch to the RUN position.
3. Measure the voltage based on the table below.
Mea- Connector terminal
Pin Connector terminal Pin
sure- name (+ terminal
No. name (- terminal side) No.
ment side)
Blower switch Blower switch
(a) <6> <3>
connector connector
Blower switch
(b) <6> Body GND –
connector
Regular: 12 V
Irregular: Large discrepancy from 12 V
(1) Control Panel (2) Blower Switch Connector
RY9212148CAS0024US0
1. Turn the key switch to the STOP position.
2. Remove the control panel from the machine and test the blower
switch independently.
(1) Control Panel (2) Blower Switch
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5-S24 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(6) Servo Motor (for Temp Control)
Checking the temperature control dial and the motor operating
angle (resistance angle)
1. Turn the starter switch to [RUN] and set the blower switch to
ON.
2. Press the A/C switch to turn the A/C on.
3. Turn the switch to the (B), (C), and (D) positions in turn as
indicated in the figure at left and measure the resistance in (A).
4. When making the measurements, first turn the starter switch to
OFF and then disconnect the servo motor's 8P connector.
5. If the resistance measured between terminals 2 and 3 of the
connector on the A/C unit side differs from the factory specs,
then either the A/C unit harness or the servo motor is faulty.
(B) Approx. 1.2 kΩ
(C) Factory specification Approx. 2.9 kΩ
(D) Approx. 4.6 kΩ
(1) 8P Connector (A) 8P Connector (A/C Unit Side)
(2) 8P Connector (A/C Unit Side) (B) Left End (Blue Side, Max Cool)
(3) Temperature Control Dial (C) Center (White Center)
(4) A/C Switch (D) Right End (Red Side, Max Hot)
(5) Fan Switch
RY9212166CAS0007US0
Servo motor inspection
1. Turn the key switch to the STOP position.
2. Measure resistance of servo motor alone.
3. Measure the resistance based on the table below.
Mea- Connector terminal
Pin Connector terminal Pin
sure- name (+ terminal
No. name (- terminal side) No.
ment side)
(a) A/C / Heater controller <7> A/C / Heater controller <8>
Regular: Approx. 33Ω (actual reference value)
Irregular: Large deviation from 33Ω
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5-S25 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(7) Pressure Switch
When a pressure switch (inside the high-pressure/low-pressure
switch) is operating normally, electricity is conducted (ON) and
when an abnormal pressure occurs, it trips the switch, blocking the
electricity (OFF).
RY9212001CAS0046US0
Manifold gauge connections
1. Close the HI (high-pressure side) valve (3) and the LO
(low-pressure side) valve (2) of the manifold gauge (1) securely.
2. Connect the red charging hose (4) to the HI (high-pressure side)
charge valve (1) and the blue charging hose (5) to the LO
(low-pressure side) charge valve (2).
3. Open the manifold gauge's HI (high-pressure side) valve (3) a
little and press on the valve core to expel any air inside its
charging hose (4). Then close the HI (high-pressure side) valve
(3) tightly.
4. Open the manifold gauge's LO (low-pressure side) valve (2) a
little and press on the valve core to expel any air inside its
charging hose (5). Then close the LO (low-pressure side) valve
(2) tightly.
(1) Manifold Gauge (4) Red Charging Hose
(2) Low-Pressure Valve (5) Blue Charging Hose
(3) High-Pressure Valve
RY9212001CAS0047US0
When refrigerant pressure is rising (OFF)
1. Start the engine and set it at 1,500 rpms. Turn the AC switch on
the control panel on, set the fan switch to HI and set the
temperature control lever to the max cool position.
2. Cover the front of the condenser with cardboard or the like and
raise the pressure on the high-pressure side of the AC cycle.
3. Once the pressure on the high-pressure side rises, the
high-pressure switch operates, turning the magnetic clutch of
the compressor off. When it does so, read the HI
(high-pressure) gauge of the manifold gauge and if it reads
higher than the pressure setting, replace the pressure switch
(8).
• Pressure setting on the high-pressure side of the switch:
Switches off at approximately 3.14 MPa (32 kgf/cm2, 460 psi) or
higher
RY9212001CAS0048US0
When refrigerant pressure is dropping (OFF)
1. Remove the connector of the pressure switch.
2. Measure the resistance between the terminals of the pressure
switch with a circuit tester. It should register 0 Ω unless there is
insufficient gas due to a leak or unless the pressure switch is
faulty.
• Pressure setting on the low-pressure side of the switch:
Switches off at approximately 0.196 MPa (2.0 kgf/cm2, 28 psi)
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5-S26 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
[2] DISASSEMBLY AND ASSEMBLY
Diagram of AC Unit
(1) Top Case (9) Expansion Valve (17) Clip (25) Cap (Plug)
(2) Evaporator (10) Expansion Bolt (18) Washer Screw (26) Blower Fan
(3) Bottom Case (11) Thermistor ASSY (19) O-Ring (27) Wire Harness
(4) Linkage Cover (12) Thermistor Clamp (20) Servo Motor (28) AC Collar
(5) Intake Cover (13) AC Amp (21) Linkage Lever (29) Flat Washer
(6) Evaporator (14) Heater Core (22) Blower Resistor (30) Bolt
(7) O-Ring (15) Pipe (23) Tapping Screw (31) Air Conditioning Unit
(8) O-Ring (16) Water Valve (24) Tapping Screw
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5-S27 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(1) Connecting / Disconnecting AC Hoses
(1) Air Conditioning Unit
(2) Compressor and Magnetic Clutch
(3) Condenser
(4) Receiver
(5) Hose (Discharge)
(6) O-Ring
(7) Hose (Suction)
(8) O-Ring
(9) Hose (Liquid, Pressure)
(10) O-Ring
(11) Pressure Switch
(12) Hose (Liquid)
(13) O-Ring
(14) Tube Connector
(15) Joint
(16) O-Ring
(17) Receiver Holder
(18) Bolt (M6)
(19) Bolt (M6)
(20) Bolt (M6)
(When removing)
1. Collect the refrigerant from the AC system.
2. Disconnect the negative (–) cable from the battery and the 1P connector of the magnetic clutch.
3. Remove the AC hoses.
CAUTION
• After removing hoses, immediately seal the AC system so no moisture or water gets into it.
(When attaching)
• Pay attention to whether each hose is for high or low pressure.
• Pay attention to whether each hose is an inlet or outlet hose.
• Attach each bolt and tighten to its specified torque.
• Tighten the nuts for aluminum pipe with two wrenches, holding one side from turning and tightening the nut to it.
(The mating side is soft, so be careful when tightening.)
• Tighten carefully so the pipe does not turn.
• Apply some compressor oil to pipes that have O-rings and press the tip into the stepped surface.
RY9212166CAS0008US0
AC Hoses Tightening Torque
7.9 to 11.8 N·m
Compressor part
0.8 to 1.2 kgf·m
M6 bolt (18)
5.8 to 8.7 lbf·ft
Condenser part
M6 bolt (19) 4.0 to 6.8 N·m
Tightening torque 0.4 to 0.7 kgf·m
Receiver part 3.0 to 5.0 lbf·ft
M6 bolt (19)
2.3 to 4.2 N·m
Air conditioning unit part
0.2 to 0.4 kgf·m
M6 bolt (20)
1.7 to 3.0 lbf·ft
RY9212166CAS0017US0
5-S28 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(2) Mounting and Removing the Compressor
(1) 1P Connector (Magnetic (5) Bolt (10) Bolt (15) Bolt
Clutch) (6) Compressor Bracket (11) Washer (16) Bolt
(2) Compressor Assembly (7) Bolt (12) Nut (17) Clip
(3) A/C Drive Belt (8) Bushing (13) Tensioner Pulley
(4) Clutch Assembly (Magnet (9) Bushing Flange (14) Tensioner Pulley Support (L) Belt Tension Checking
Compressor) Position
(To be continued)
5-S29 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(Continued)
(When removing)
1. Collect the refrigerant from the A/C system.
2. Disconnect the negative (-) cable from the battery and
disconnect the 1P connector of the magnetic clutch.
3. Remove the low-pressure pipe and the high-pressure pipe from
the compressor, then immediately cap them so no water or
moisture gets into the A/C system.
4. Remove the A/C drive belt and then the compressor.
(When attaching)
• Adjust the tension of the compressor drive belt. The tension is
correct if the belt is displaced 12 to 15 mm when the L part of
the belt is pressed down with your fingertips [68.6N (7kgf)].
• Attach each bolt and tighten to its specified torque.
• Apply compressor oil to the O-rings.
• Connect the low-pressure hose to the side of the compressor
marked "S" (suction). Make sure that bolts are installed in the
correct direction.
• Connect the high-pressure hose to the side of the compressor
marked "D" (discharge). Make sure that bolts are installed in the
correct direction.
• Make sure the bushing is installed the right way round.
16.7 to 19.6 N·m
Mounting bolt (5), (7) 1.7 to 2.0 kgf·m
12.3 to 14.5 kgf·ft
Tightening torque
17.7 to 20.6 N·m
Lock nut (11) 1.8 to 2.1 kgf·m
13.1 to 15.2 lbf·ft
(17) Low-Pressure Pipe (A) Bolt Installation Direction
(18) High-Pressure Pipe
(19) Bolt
RY9212166CAS0014US0
Filling the compressor with oil
When replacing the compressor
• The amount of oil required by the new compressor is enclosed
within the AC cycle. A certain amount of compressor oil
circulates along with the gas in the AC system.
• When replacing the compressor, remove the excess oil from the
new compressor.
• Compressor oil (ND-OIL8) readily absorbs moisture, so seal it
immediately.
Capacity
Compressor Oil Type: ND-OIL8 (reference value):
60 cc, 0.06 U.S.qts
(1) New Compressor A : Amount of Oil for New
(2) Old Compressor Compressor
B : Amount of Oil from Old
Compressor
(a) Remove Excess Oil (A-B)
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5-S30 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Adjusting clearance
1. Use a feeler gauge to check the clearance.
2. If the measurement is outside the factory specification, adjust
the clearance.
0.30 to 0.65 mm
Clearance Factory specification
0.0118 to 0.0255 in.
[NOTE]
Shim Thickness Part No.
0.10 mm (0.0039 in.) T1065-87340
0.15 mm (0.0059 in.) T1065-87350
0.40 mm (0.016 in.) T1065-87360
0.60 mm (0.024 in.) T1065-87370
1.0 mm (0.0394 in.) T1065-87380
(1) Magnetic Clutch Mounting Screw (6) Snap Ring
(2) Hub Plate (7) Stator
(3) Shim (8) Compressor Body
(4) Snap Ring
(5) Rotor L : Clearance
RY9212148CAS0010US0
5-S31 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(3) Connecting / Disconnecting Hoses
(1) Pipe Joint (R3/8) (4) Protective Tube (6) Hose Clamp (a) Engine Side
(2) Hose Clamp (Spring Type) (5) Pipe Joint (S, R3/-14) (7) Bottom of Machine (b) A/C Unit Side
(3) Heater Hose (c) 45 °
(d) 30 °
(When removing)
1. Stop the engine and allow the radiator to cool before starting work.
2. Drain the coolant (hot water) from the engine side.
3. Simultaneously remove the heater hose from the water flange side and drain the coolant (hot water).
4. Remove the heater hose on the heater core side.
(When attaching)
• Be careful not to mistake the inlet and outlet hoses.
24.5 to 29.4 N·m
Tightening torque Pipe joint (1), (5) 2.5 to 3.0 kgf·m
18.1 to 21.7 lbf·ft
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5-S32 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Handling engine coolant
(when draining)
1. Stop the engine and start working once the radiator has cooled.
2. Remove the reserve tank hose from the radiator.
3. Remove the drain plug from the radiator, then remove the
radiator cap and drain out all of the coolant.
(When filling)
1. Tighten the drain plug securely and replace the reserve tank
hose to the radiator.
2. Fill the radiator and the reserve tank with coolant.
3. After filling, tighten the cap, start the engine, let it idle for five
minutes, stop the engine and check and make sure it has the
specified amount of coolant.
(1) Coolant Drain Plug (2) Radiator Cap
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5-S33 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(4) Removing and Mounting the Receiver
(1) Condenser
(2) Cushion
(3) Grommet
(4) Thrust Collar
(5) Bolt
(6) Plate
(7) Bolt
(8) Receiver
(9) Holder
(10) Bolt
(11) Bracket
(12) Bolt
(13) Joint
(14) O-Ring
(15) Bolt
(16) Hose
(17) Flange Bolt
(18) Bracket
(19) Hose
(20) Hose
(21) Flange Bolt
(When removing)
1. Remove the receiver and its bracket.
2. Remove the plate from the bracket.
3. After removing the plate and the cushion, remove the
condenser.
CAUTION
• The receiver has a desiccant in it, so do not remove its
rubber cap until just before connecting its hoses.
Be careful not to damage the fins of the condenser.
(When attaching)
• Be careful of the orientation of the thrust collar when installing it.
• Be careful not to mistake an inlet hose for an outlet hose.
• Attach each bolt and tighten to its specified torque.
NOTE
Part Replaced Fill Capacity Brand Name
40 cc
Condenser
0.04 U.S.qts
40 cc
Evaporator
0.04 U.S.qts
ND-OIL8 <PAG* oil>
10 cc
Receiver
0.01 U.S.qts
20 cc
Hose
0.02 U.S.qts
*PAG : Polyalkylene glycol (synthetic oil)
RY9212001CAS0058US0
5-S34 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(5) Removing and Mounting AC Ducts
(1) Duct ASSY (1, AC)
(2) Duct
(3) Seal
(4) Seal
(5) Seal
(6) Duct ASSY (2, AC)
(7) Duct
(8) Seal
(9) Seal
(10) Seal
(11) Seal
(12) Bolt
(13) Duct ASSY (3, AC)
(14) Duct
(15) Duct
(16) Seal
(17) Seal
(18) Insulation (2, AC)
(19) Air Conditioning Unit
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5-S35 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(When removing)
1. Remove the two bolts and then the duct cover (1).
2. Remove the two bolts and then the switch cover.
3. Remove the four bolts and then the duct cover (3).
4. Remove the duct ASSY (3, AC) from the duct ASSY (1, AC).
5. Remove just the one bolt and then remove the duct ASSY
(2, AC) from the duct ASSY (1, AC).
6. Remove the duct ASSY (1, AC) from the air conditioning unit.
(When attaching)
• All the duct assemblies fit together.
• Press the parts that fit together in firmly until the seal is hidden.
• Attach the bolts and tighten them to the specified torque.
(1) Duct Cover (5) Bolt
(2) Switch Cover (6) Duct ASSY (2, AC)
(3) Duct Cover (7) Duct ASSY (1, AC)
(4) Duct ASSY (3, AC)
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5-S36 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(6) Removal and Installation of AC Cabin Air Inlets
(1) Duct ASSY (1, Air-Intake, A/C)
(2) Duct
(3) Seal
(4) Seal
(5) Duct
(6) Duct ASSY (Air-Intake, Base)
(7) Duct
(8) Seal
(9) Seal
(10) Seal
(11) Seal
(12) Filter
(13) Cover
(14) Spring Plate
(15) Screw with Washer
(16) Spring Plate
(17) Screw with Washer
(18) Seal
(19) Seal
(20) Plate
(21) Seal
(22) Lever
(23) Knob Bolt
(24) Bolt
(25) Duct ASSY (3, Air-Intake, A/C)
(26) Duct
(27) Seal
(28) Insulation Heat
(29) Bracket
(30) Cover
(31) Air Conditioning Unit
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5-S37 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
(When removing)
1. Remove the bolts at the two spots, and also remove the duct
cover.
2. Remove the bolts at the two spots, and also remove the Switch
cover.
3. Remove the bolts at the two spots, and also remove the duct
assy (air-intake, base).
4. Remove the duct assy (3, air-intake, A/C) and duct.
5. Remove the duct assy (1, air-intake, A/C) from the A/C unit.
Replacing the Filters
1. Loosen the knob bolt.
2. Pull the right edge of the cover front and remove the hook out of
the spring plate.
3. Remove the insertion of left edge of the cover.
4. Remove the filters.
(When Attaching)
• (A) Insert the filters in the clearance of upper and lower of the
duct. (the filter's convex surface is at the cover side.)
• (B) Insert the nail part of left edge of the cover into the slit part
and push the right edge to the spring plate until it hooks.
• (C) Tighten the cover with the duct and the knob bolt.
1. Insert and attach the duct assy (3, air-intake, A/C) into the duct
assy (air-intake, base) and the bracket.
2. Insert and attach the duct assy (1, air-intake, A/C) into the A/C
unit.
3. Insert and attach the duct into duct assy (1, air-intake, A/C) and
duct assy (air-intake, base).
(1) Knob Bolt (7) Duct ASSY
(2) Cover (8) Duct ASSY (Air-Intake, Base)
(3) Duct (9) Duct ASSY (3, Air-Intake, A/C)
(4) Filter (10) Bracket
(5) Spring Plate (11) Duct Cover
(6) Duct ASSY (1, Air-Intake, A/C) (12) Switch Cover
RY9212032CAS0002US0
5-S38 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
7. CABIN REMOVAL AND MOUNTING
[1] REMOVING THE CABIN
1. Put the bucket on the ground, stop the engine, and slide the
seat forward of the machine.
2. Remove the cover (1), (2), (3) and the filter (4).
(1) Cover (3) Cover
(2) Cover (4) Filter
RY9212032CAS0003US0
3. Disconnect the harness for cabin and the coupler connecting
the main harness.
4. Remove the cover (1).
(1) Cover (3) Harness Coupler for Cabin
(2) Main Harness Coupler
RY9212032CAS0004US0
5. Remove the air duct (1) and (2).
(1) Air Duct (2) Air Duct
RY9212032CAS0005US0
6. Remove the floor mat and the two nuts (1) at the front of the
machine to attach the cabin.
107 to 127.4 N·m
Tightening torque Nut (1) 11.0 to 13.0 kgf·m
79.69 to 92.6 lbf·ft
(1) Nut
RY9212032CAS0006US0
7. Remove the two nuts (1) at the rear of the machine to attach the
cabin.
107 to 127.4 N·m
Tightening torque Nut (1) 11.0 to 13.0 kgf·m
79.69 to 92.6 lbf·ft
(1) Nut
RY9212032CAS0007US0
5-S39 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
78 to 127 N·m
Stud (front) (6)
Tightening torque 8.0 to 13.0 kgf·m
Stud (rear) (7)
58 to 94 lbf·ft
Spread the screw fixation medicine (Loctite 271).
(1) Nut (6) Stud (Front)
(2) Washer (7) Stud (Rear)
(3) Shock Absorber Rubber
(Cabin, Upper) (A) Two Points at the Front of the
(4) Shock Absorber Rubber Machine
(Cabin, Lower) (B) Two Points at the Rear of the
(5) Collar Machine
RY9212032CAS0008US0
8. Hook the nylon sling at the top of the cabin and hold it.
RY9212166CAS0009US0
Lift the cabin gently and remove it.
Cabin mass approx. 230 kg / 507 lbs.
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5-S40 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
8. WINDOW WASHER
[1] WIPER SWITCH
Connector voltage
1. Remove the 6P connector from the wiper switch.
2. Switch the starter switch to [RUN] and the wiper switch to ON.
3. Measure the voltage between terminal 1of the connector on the
harness side and ground on the body.
4. If is the same as the battery voltage (DC 11 to 14 V), it is normal.
(1) Wiper Switch A : 6P Connector (Harness Side)
RY9212001CAS0071US0
Checking the wiper switch
1. Check the continuity between each of the terminals according to
the table below.
2. If continuity exists, it is normal.
A : 6P Connector (Switch Side)
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5-S41 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Checking the cab wiper power harness
1. Disconnect the 6P connector from the wiper switch and the 4P
connector from the cab wiper power harness.
2. Check the continuity between the terminals on both sides of the
harness.
3. If continuity exists, it is normal.
(1) Cab Wiper Power Harness A: 6P Connector
B: 4P Connector
(a) Wiper Motor Line
(b) Washer Motor Line
RY9212001CAS0073US0
[2] COMPONENT SCHEMATIC
(1) Wiper Motor ASSY
(2) Nut
(3) Wiper Cap
(4) Nut
(5) Washer
(6) Wiper Seal
(7) Wiper Plate
(8) Wiper Cover
(9) Bolt
(10) Cushion
(11) Flange Nut
(12) Wiper Arm ASSY
(13) Wiper Blade
(14) Nozzle ASSY
(15) Gasket
(16) Gasket
(17) Elbow Joint
(18) Tube Joint
(19) Screw
(20) Washer Tank
(21) Bracket
(22) Bolt
(23) Tube
(24) Clamp
(25) Washer motor
The wiper is installed on the front and is composed of a wiper motor, wiper arm, wiper blade, etc.
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KX057-4,U55-4, WSM CABIN
[3] WIPER MOTOR
Checking the Voltage
1. Remove the wiper motor connector.
2. Start the engine and turn the wiper switch ON.
Measure the voltage based on the table below.
Mea-
sure-
Connector Name Connector Name
ment Pin No. Pin No.
(+terminal side) (- terminal side)
Point
s
(a) Wiper motor connector <1> Wiper motor connector <2>
(b) Wiper motor connector <3> Wiper motor connector <2>
Regular: 12 V
Irregular: Large discrepancy from 12 V
(1) Wiper Motor A : Wiper Motor Connector
RY9212148CAS0019US0
Testing the motor separately
1. Raise the wiper blade so there is no load on it.
2. Switch the starter switch to [RUN] and the wiper switch to ON.
3. If the rpm and wiping angle are as indicated in the table, it is
normal.
No load wiper rpm 25 to 43 rpm
Factory specification
No load wiping angle 87 to 93 °
3.43 to 4.41 N·m
Flange nut (11) 0.35 to 0.45 kgf·m
2.5 to 3.3 lbf·ft
2.94 to 3.92 N·m
Tightening torque Nut (4) 0.30 to 0.40 kgf·m
2.0 to 3.0 lbf·ft
6.37 to 9.32 N·m
Nut (2) 0.65 to 0.95 kgf·m
4.7 to 6.9 lbf·ft
A : Wiper Motor Connector
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5-S43 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
[4] WASHER MOTOR
Checking the Voltage
1. Remove the washer motor connector.
2. Start the engine and turn the wiper switch ON.
Measure the voltage based on the table below.
Mea-
sure-
Connector Name Connector Name
ment Pin No. Pin No.
(+terminal side) (- terminal side)
Point
s
Washer motor Washer motor
(a) <2> <1>
connector connector
Regular: 12 V
Irregular: Large discrepancy from 12 V
(1) Washer Tank (2) Washer Motor Connector
RY9212148CAS0020US0
5-S44 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
9. LIGHTING DEVICES (CAB WORK LIGHT, INTERIOR
LIGHT)
(1) Wire Harness (Cabin)
(2) Wire Harness
(3) Grommet
(4) Bolt (Earth)
(5) Cabin Working Light
(6) Light Bulb
(7) Lamp Cover
(8) Wiper Cover
(9) Bolt
(10) Lamp Bracket Assy
(11) Bolt
(12) Room Light Assy
(13) Light Bulb
(14) Screw
RY9212032CAS0011US0
Connector voltage
1. Disconnect the cab power 8P connector from the wire harness
(cabin).
2. Measure the voltage between terminal 3 of the connector on the
cabin power harness side and ground on the body.
(interior light)
3. Turn the starter switch to [RUN].
4. Measure the voltage between terminal 4 of the connector on the
cabin power harness side and ground on the body. (cab work
light)
5. If is the same as the battery voltage (DC 11 to 14 V), the
connector voltage is normal.
(1) Cab Power Harness A : 8P Connector
(Cab Power Harness Side)
B : 8P Connector
(Cab Harness Side)
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KX057-4,U55-4, WSM CABIN
Terminal voltage (cab work light)
1. Remove the grommet and pull the work light terminal out of the
frame of the cabin.
2. Remove the two work light terminals.
3. Switch the starter switch to [RUN] and the cab work light switch
to ON.
4. Measure the voltage between GND and the work light terminal
(+) on the harness side.
5. If is the same as the battery voltage (DC 11 to 14 V), the
terminal voltage is normal.
(1) Work Light (a) (+) Terminal
(2) Grommet (b) GND Terminal
RY9212001CAS0081US0
Terminal voltage (interior light)
1. Remove the cover of the interior light.
2. Remove the bulb. (pull it out)
3. Switch the interior light switch to [ON].
4. Measure the voltage between GND and the interior light
terminal (+).
5. If is the same as the battery voltage (DC 11 to 14 V), the
terminal voltage is normal.
(1) Interior Light ASSY (a) (+) Terminal
(2) Interior Light Switch (b) GND Terminal
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5-S46 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
Cab work light switch
Connector voltage
1. Turn the starter switch to [OFF] and disconnect the 10P
connector from the cab work light switch.
2. Turn the starter switch to [RUN].
3. Measure the voltage between terminal 7 of the connector on the
harness side and ground on the body. (switch voltage)
4. Measure the voltage between terminal 4 of the connector on the
harness side and ground on the body. (LED voltage)
5. If is the same as the battery voltage (DC 11 to 14 V), it is normal.
(1) Cab Work Light Switch (A) 10P Connector (Harness Side)
(2) 10P Connector (Harness Side)
RY9212166CAS0015US0
Checking the cab work light switch
1. Check the continuity between each of the terminals according to
the table below.
2. If continuity exists, it is normal.
(1) Cab Work Light Switch (a) (Free)
(2) 10P Connector (Switch Side)
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KX057-4,U55-4, WSM CABIN
10. REMOVAL AND INSTALLATION OF GLASS
[1] PREPARATION
Items required
• Cleaner : Equivalent of Seeker Cleaner 205
• Adhesive : Equivalent of Seeker Flex 250PC-JM
• Primer : Equivalent of Seeker Primer 206
• Scraper
• Awl
• Adhesive cutter
• Glass suction cups (use if needed)
NOTE
• The cleaner and adhesive have a short shelf-life (9 to 12
months), so obtain them immediately before use from a
nearby manufacturer or a shop that handles auto glass
products.
(1) Glass Suction Cups (2) Adhesive Cutter
RY9212001CAS0085US0
[2] REMOVING GLASS
CAUTION
• The section on removing and installing glass was created as a general explanation of the work method
and it may differ from the removal/installation methods for glass installed on the machine covered by this
workshop manual.
RY9212148CAS0035US0
1. Mask off painted surface around the glass to protect them from
scratching while removing/installing glass.
2. Remove the glass.
[When using piano wire (damages parts of the glass)]
• Pierce and make a hole in the adhesive with an awl (or knife of
glass cutter, etc.).
• Pass the piano wire (or steel wire) through the hole.
• Wrap both ends of the piano wire around a wood block or the
like.
• Pull the piano wire along the edge of the window, sawing
through the adhesive between the cab and the glass; then
remove the glass from the cab.
[When using an adhesive cutter (completely ruins the glass)]
• Insert the adhesive cutter into the adhesive.
• Pull on part (a) of the cutter and cut the glass out.
CAUTION
• If the piano wire gets very hot in one place, it may break.
Avoid rubbing it with much force against the edge of the
glass.
• Be careful not to cut yourself on fragments of glass or the
blade of the cutter.
(1) Cab Frame (5) Piano Wire
(2) Glass (6) Wood
(3) Awl (7) Adhesive Cutter
(4) Adhesive
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KX057-4,U55-4, WSM CABIN
[3] INSTALLING GLASS
1. Completely eliminate all old adhesive on the frame of the cab.
2. Use the cleaner to clean the cab frame and the surface of the
new glass where adhesive will be applied to get rid of any dirt or
oil.
3. Affix the windshield dam to the surface of the new glass where
the adhesive will be applied.
4. Apply primer uniformly around the circumference of the
windshield dam.
5. Apply adhesive uniformly along the outer circumference of the
windshield dam.
6. Apply primer uniformly around the entire circumference of the
flange of the cab frame. (Application width: 18 mm (0.71 in.) or
more)
7. Make and install a spacer for in between the edge of the glass
and the cab's frame so that the glass does not slide down during
installation. (holds position and prevents slipping)
8. Press slightly all the way around the edge of the glass from the
outside, so the glass touches the shield dam and they stick
together.
9. Hold the glass in place with packing tape until the adhesive
hardens so the glass does not shift or come off.
(1) Glass (a) At Least 7 mm (0.28 in.)
(2) Windshield Dam (W/Adhesive) (b) At Least 12 mm (0.47 in.)
(3) Primer (Apply) (c) 12 mm (0.47 in.)
(4) Adhesive (Apply) (A) Start Affixing Dam Here
RY9212001CAS0087US0
• For the front window
(1) Glass (a) At Least 7 mm (0.28 in.)
(2) Windshield Dam (W/Adhesive) (b) At Least 12 mm (0.47 in.)
(3) Adhesive (Apply)
(4) Fastener (Affix as Male/Female Set) (A) Line Up with the Edge of the
Frame
RY9212001CAS0088US0
• Recommended shape of triangular bead
NOTE
• Cut the tip of the nozzle of the adhesive cartridge in the
shape of a V.
• Apply the adhesive to the glass so it forms a uniform
triangular bead.
(1) Nozzle Tip (a) At Least 8 mm (0.31 in.)
(2) Windshield Dam (W/Adhesive) (b) At Least 12 mm (0.47 in.)
(3) Adhesive (Apply)
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KX057-4,U55-4, WSM CABIN
[4] GLASS TRIM TYPE
(When removing)
1. Lift the rubber core by its seam and remove it.
2. Remove the glass to the outside.
(When attaching)
1. From the outside, insert the glass into the glass trim.
2. Insert the rubber core into the groove all the way around the
trim.
3. Start inserting the rubber core at the bottom center. (to prevent
rain from getting in)
(1) Panel (a) Inside
(2) Glass Trim (b) Start Here
(3) Rubber Core
(4) Glass
RY9212001CAS0090US0
[5] HOW TO REPLACE THE GLASS OF THE RIGHT-SIDE WINDOW
Put something like a piano wire into the outer window frame, pull it along the frame, remove the adhesive agent
and cut it off from the cab frame. Replace the window glass followed by the next procedure.
RY9212032CAS0012US0
How to replace the glass
1. Lift the pin up with a flat-head driver.
For RD451-46041, remove the sealant first and lift the pin.
2. Open the window to the point as shown in the figure.
3. Push down to widen up the window frame within elastic
deflection not enough to deform itself permanently and replace
the glass.
And the same way when you install the glass.
4. Put the pin back.
Apply sealant on this part of RD451-46041.
NOTE
• Use same brand of an adhesive agent and a primer
E.g.)
– Cleaner: TK cleaner made in Daishin Chemistry
– Adhesive agent: Sikaflex-260AP (SikaTack-Go!) or MSI
made Sunrise U90
– Primer: Sika Coating Activator or MSI made Sunrise
Primer 24
(1) Pin (A) Push Down to Widen Up the
(2) Window Window Frame
RY9212032CAS0013US0
5-S50 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
How to apply primer on the cab side
1. Remove dirt and grease on the opening surface of the glass
sash's flange with a cleaner such as white gasoline. Avoid using
an alcoholic cleaner.
2. Apply body primer evenly all around of flange from the end.
NOTE
• You have to finish the glass installation within 3 min. to
6 hours after coating the primer.
(1) Primer (Apply) (a) 18 mm (0.71 in.) or more
RY9212032CAS0014US0
How to install the glass spacer
1. Remove dirt and grease on the surface of glass spacer with a
cleaner such as white gasoline.
2. Apply the primer to the glass spacer.
3. Install the glass spacer in the glass sash. (4 spots)
(1) Glass Spacer (a) 100 mm (3.9 in.)
(b) Cross Section of the Spacer
(c) Install in the Sash
(d) Inclined Surface
(e) Cab Side
RY9212032CAS0015US0
How to install the sealant dam and apply the primer
1. Remove dirt and grease on the surface of the circumference at
the back of the sash glass to apply an adhesive agent and on
the surface of applying a sealant dam with a cleaner such as
white gasoline. Avoid using an alcoholic cleaner.
2. Put a sealant dam on the position as shown in the figure and
evenly apply the primer peripherally.
[ How to apply adhesive ]
1. Apply the adhesive along the circumference of the sealant dam.
NOTE
• You have to finish the glass installation within 3 min. to
6 hours after coating the primer.
• In order to keep water-tightness, the adhesive must be
applied unbrokenly.
• Installation of glass needs to be done within 3 min. after the
adhesive is applied.
(1) Sealant Dam (W/Adhesive) (a) 12 mm (0.47 in.)
(2) Primer (Apply) (b) 12 mm (0.47 in.) or more
(3) Adhesive (Apply) (c) 7 mm (0.27 in.) or more
(A) Starting Point of Installation
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5-S51 KiSC issued 04, 2021 A
KX057-4,U55-4, WSM CABIN
How to install the glass sash
1. Set the glass in the sash on which the adhesive has been
already applied and install to attach on the cabin frame.
NOTE
• Adhesive should not be run off the edge of the sash after
the glass sash is set.
• Need to maintain that state for about 24 hours after the
glass sash is set.
(1) Glass Sash
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KX057-4,U55-4, WSM CABIN
11. FRONT WINDOW
[1] ADJUSTING THE CLOSING LOCK OF THE FRONT WINDOW
(TOP)
When water leaks in the cabin or it rattles
1. Close the front window (top) and lock it securely.
2. Remove the trim on the top edge of the front window (top) about
half way along the frame and measure the clearance between
the glass and the cab frame.
NOTE
• If you remove the trim too far, the glass may shift out of
position, preventing a reliable measurement of the
clearance.
(1) Cab ASSY (a) Clearance
(2) Front Window (Top)
(3) Trim
(4) Cab Frame
RY9212001CAS0091US0
3. Remove the clip and then the lock cover.
(1) Lock Cover (2) Clip
RY9212001CAS0092US0
4. Remove the lock of the front window (top) and loosen the lock's
mounting bolts.
5. Leave the rear bolt as is and lift up the front bolt 1.0 to 1.5 mm
(0.04 to 0.06 in.).
NOTE
• Lifting the bolt more than 1.5 mm (0.06 in.) may prevent the
lock from working.
6. Re-tighten the bolts to the specified torque.
7. Close the front window (top) and lock it securely.
8. Recheck the clearance between the glass and the cab frame
and make sure the clearance is smaller.
9. Operate the machine and make sure the rattling has stopped
while driving.
10. Spray some water on the window and make sure it does not
leak.
(1) Lock (3) Bolt (Rear)
(2) Bolt (Front)
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KX057-4,U55-4, WSM CABIN
[2] ADJUSTING THE OPEN LOCK OF THE FRONT WINDOW (TOP)
When it rattles on the cabin
1. Lift the front window (top) and lock it securely to the ceiling.
2. While pulling down on the handle, check whether there is a gap
between the glass and the cushion.
3. If the glass is up against the cushion without a gap, it is OK.
4. If there is a gap between the glass and the cushion, it causes
the rattling. Loosen the nut and stretch the cushion until it is
against the surface of the glass.
5. After adjusting the cushion, re-tighten the nut.
6. Lift the front window (top) and lock it securely to the ceiling.
7. Operate the machine and make sure the rattling has stopped
while driving.
(1) Cabin (3) Cushion
(2) Nut (4) Handle
RY9212001CAS0094US0
5-S54 KiSC issued 04, 2021 A
W/H33 CORD,BATTERY(-)
CORD,BATTERY(-)(MAIN_FRAME)
CRSD & N_BI: 40 f B/R BASE: 40.00 B/Y
CORD,BATTERY(-)(BATTERY) W/H33
W/H33
GND1 BASE: 3 B BASE: 3 B
BODYEARTH(MAIN_FRAME)
+ BASE: 40.00 B/Y GND2
BATTERY W/H34 GND3 GND3 GND2 GND1 GND3
- GND1:POWER
BATTERY_TERMINAL,N_BI GND2:ECU,SENSOR
N_BI: 8.00 R SWING_FRAME
GND3:SHIELD(SENSOR)
ENGINE
1
W/H34 CORD,BODY EARTH BODYEARTH(ENGINE)
BATTERY(POWER),N_BI MAIN(POWER),N_BI
N_BI: 8.00 R N_BI: 8.00 R
1 1
W/H00 W/H30
SBF(MAIN2) SBF,MAIN1-2
BASE: 5 R/Y
50 2 2
Plug-in_type
Composition Specification Code Notes
SBF(MAIN1) W/H00 RD568-53310 W/H(MAIN,CNP)
50
BASE: 5 R
BASE ALL-USE RD568-53330 W/H(MAIN,CNP,ANG)
START
1 1
SWITCH,STARTER
OFF
ON
BASE: 3 R
Plug-in_type RD568-53420 W/H(MAIN,CAB,AC)
AI Auto Idle
HT: AC: 5 R/Y
HT: AC: 5 R/Y
SBF(CRS) KEY_SWITCH RD568-53430 W/H(MAIN,CAB,ACAB)
N_BI: 5 R
BASE: 5 R
AUX2: AUX1: 5 R
N_BI: 5 R
3 R
BASE: 5 R
BASE: 3 R
BCN: 5 R
SBF-BOX
CRSD: CRSB: 3.00 R BASE: 3 R/W
30 3 3 1
R/W
AT Anti-Theft W/H06 RD158-5348K W/H(A/C)
CRSD:
Bolt-in_type BASE: 3.00 B/W B/W
No.Battery Isolator
2 N_BI W/H11 RD568-53491 W/H(GS,INTERMEDIATE)
BASE: 3 R/W
BASE: 3 R/W
BASE: 3 R/W
BASE: 3 R/W
BASE: 3 R R
SBF-BOX SBF(ALTERNATOR) SBF-BOX
W/H12 RD451-53360 W/H(FRONT)
BASE: 3 B/W
3
BASE: 8.00 R N_B AT&N_BI Anti-Theft & No.Battery Isolator
2 2 80 4 4 I: 8
.00 W/H19 RD451-46900 W/H(MAIN,CAB)
Bolt-in_type R
ES Engine Stop
SBF_BOX RD451-54311 W/H20 RD451-46910 W/H(WIPERCODE)
BCN Beacon W/H23 RD451-53380 W/H(CANOPY,4P)
CRSD: 3 W
CAB: 3 W
CAB: 3 W
HT: AC: 3 W
RELAY(40A,ISO) TRB Travel Alarm W/H30 RD451-53222 CORD,BATTERY(+)
RELAY(POWER) RELAY(POWER)
W/H33 RD451-53232 CORD,BATTERY(-)
BASE: 5 R/Y 30 87 BASE: 3 W AC A/C
3 4
BASE: 0.50 L 86 85 BASE: 0.30 B W/H34 RD451-53242 CORD,BODY EARTH
1 2 EP Eco Power Mode
GND2
AUX1 Grip (L)
AUXC Grip (L) (CAP)
AUX2 Grip (R)
ALTERNATOR,ASSY(60A) AT&AUX1 Anti-Theft & Grip (R)
ALTERNATOR(+B)
1J730-64011
BASE: 8.00 R +B
B-1 CAB CAB (8+4)
BASE: 1.25 f Y/R IG
FUSE(ALTERNATOR) FUSE(ALTERNATOR) FUSE(ALTERNATOR) STARTER(50),D BASE: 0.75 f W/R
A-1
L CNP Canopy
BASE: 3 R/W BASE: 1.25 f Y/R CRSD: 3 B/W 50 A-2
10 A-1 ALTERNATOR(IG,L) NB Normal Blade
CRSD & N_BI: 40 f B/R
MiniFuses 30_+B
MIC
RD451-54101 RELAY(STARTER) B-1
Angel Blade
RELAY(STARTER)
STARTER(+B),D AB
B/W
RELAY(STARTER)
NULL
D:
3 ASSY_STARTER N_FS No.Fuel Supply-pump
BASE: 3 B/W
4 CRS M
30 87
3 5
BASE: 0.50 R/B 86 85 BASE: 0.50 R/W MF Multi
1 2
CRSD CRS-DENSO
CRSD&N_BI CRS-DENSO & No.Battery Isolator
RELAY(40A,ISO) 4-Cylinder
RELAY(GLOW),4 RELAY(GLOW),4
COMMON ALL-USE
CRSD: 3 R 30 87 CRSD: 3 R/B
PLUG,GLOW
3 4 GLOW,D
CRSD: 1.25 R/B 86 85 CRSD: 0.50 B/R
1 2 1
ON OFF SW(DPF,INHIBIT)
(V0511-53822)
OFF ON
SWITCH(DPF,INHIBIT) SWITCH(E/P,CHANGE)
CRSD: 0.30 R/B Vcc(12V) E/F_CHANGE_SWITCH
7 SWITCH(DPF,INHIBIT) BASE: 0.30 R/B AC
OFF 7 E/F_CHANGE_SWITCH
9 OFF
SIGNAL CRSD: 0.30 G/O 9
6 ON BASE: 0.30 L/O
Null 6
8
Null 8
3
Null 3
2
CRSD: 0.30 R/B LED(AMBER) 680 LED(AMBER_GND) CRSD: 0.30 G/B 2 N_BI:
4 10 BASE: 0.30 R/B LED(+) LED(GND) BASE: 0.30 L/W 0.50 232C
Y/R 232C
CRSD: 0.30 G/O RESISTANCE(GND) 620 RESISTANCE CRSD: 0.30 B 4 10 +B
1 5 BASE: 0.30 L/O RESISTOR RESISTOR BASE: 0.30 B 4
GND2 1 620ohm 620ohm 5
GND2
BASE: 0.50 B GND
3
CRSD: 0.30 G/O BASE: 0.30 L/O GND2 BASE: 0.50 L Txd
2
BASE: 0.50 B/O Rxd
1
RELAY(ECU_MAINPOWER) AT&N
_
ANTENNA(ANTITHEFT)
BI:
RELAY(ECU_MAINPOWER) 0.30
JOINT-AIM Y/R
NULL LED+
FUSE(ECU_MAIN(POWER)) FUSE(ECU_MAIN(POWER)) FUSE(ECU_MAIN(POWER)) RELAY(ECU_MAINPOWER) 4 water-proof 6
BASE: 5 R BASE: 3 Y/R BASE: 3 Y/R 30 87 BASE: 3 Y/R AT: 0.30 R LED
30 3 5 3
BASE: 2 Y/R 86 85 BASE: 0.30 Y/G AT: 0.50 W/B +12V
MiniFuses 1 2 5
RD451-54101 AT: 0.30 W TX INOUT
SWITCH,LIMIT 1
SOLENOID(LEVER_LOCK) AT: 0.30 G RX RF
FUSE(LEVER_LOCK) FUSE(LEVER_LOCK) FUSE(LEVER_LOCK) SWITCH(LEVER_LOCK) SWITCH(LEVER_LOCK) SOLENOID(LEVER_LOCK) SOLENOID(LEVER_LOCK) 4
BASE: 3 R/W BASE: 0.50 f L/W BASE: 0.50 f L/W B B BASE: 0.50 f G/W (+) (-) BASE: 0.50 G AT: 0.30 B GND
5 2 1 1 2 2
MiniFuses GND1 ANTITHEFT_ANTENNA
0.50 G/W
RD451-54101 SWITCH(PRESSURE,25.0K)
AI_PRESSURE_SW AI_PRESSURE_SW
AI: 0.50 R/B NC NC AI: 0.50 G/W
1 2
BASE:
SWITCH(PRESSURE,25.0K)
BOOM_RAISE_SW BOOM_RAISE_SW
EP: 0.50 R/B NC NC EP: 0.50 G/R
1 2
FUSE(STARTER_SIGNAL) FUSE(STARTER_SIGNAL) FUSE(STARTER_SIGNAL)
BASE: 3.00 B/W BASE: 0.50 Y/B ECU(MAIN) ECU(MAIN) ECU(MAIN)
5 BASE: 0.50 L TxD(MAIN-ECU) CAN-H BASE: 0.50 BR/W
MiniFuses SWITCH,ASSY.ENGINE_STOP 61 60
Y/B
RD451-54101 BASE: 0.50 B/O RxD(MAIN-ECU) CAN-L BASE: 0.50 BR
80 79
BASE: 2 f B
CRSD: 0.50
MAIN-POWER BASE: 2 Y/R
STOP_SWITCH STOP_SWITCH AT: 0.30 W TxD(RF-UNIT)
ES: 0.50 W/B R G ES: 0.50 R/L 49
3 GND1
PANEL,ASSY(AI) 1 2 AI-MOTOR(+)
AI_CONSOLE AT: 0.30 G
+5V AI: 0.50 R/B
RxD(RF-UNIT)
51 AI-MOTOR(-)
SOLENOID(AUX1-R)
SOLENOID(AUX1-R) SOLENOID(AUX1-R)
1kohm,0.4W 8 AC: 0.50 Y COMPRESSOR-CRUTCH-SW AUX1: 0.50 W
AI_POT AI: 0.30 R SW1 SW2 AUX2: 0.50 W/B
7 45 BASE: 2 f B
MOTOR-GND 1 2
GND AI: 0.50 B/Y AI: 0.50 G/W
4
AI-PRESSURE-SW
50
1 SOLENOID(AUX1-L)
AI: 0.50 R/B SOLENOID(AUX1-L) SOLENOID(AUX1-L)
+12V BASE: 0.30 R/W AUX1-SOL(R) AUX1: 0.50 W
WORKLIGHT-SW AUX1: 0.50 R/W
2 SW1 SW2 AUX1: 0.50 W/B
750ohm,0.5W AUX_LED AI: 0.30 W 44 24
1 2
5 BASE: 0.50 Y/B STARTER-SW AUX1-SOL(L) AUX1: 0.50 R/W
750ohm,0.5W AI_LED AI: 0.30 L/W 46 23
1 ES: 0.50 R/L AUX2: 0.50 W/B SOLENOID(AUX2-R)
150ohm,2W AUX_SW AI: 0.30 B/R ENGINE-STOP-SW AUX1-SOL-FEEDBACK
63 19 SOLENOID(AUX2-R) SOLENOID(AUX2-R)
3
150ohm,2W AI_SW AI: 0.30 O WATERSEPARATOR-SW AUX2: 0.50 O SW1 SW2 AUX2: 0.50 O/B
6 AUX2-SOL(R) AUX2: 0.50 O 1 2
BASE: 0.30 L/O EP-MODE-SW 42 SOLENOID(AUX2-L)
65 AUX2-SOL(L) AUX2: 0.50 P SOLENOID(AUX2-L) SOLENOID(AUX2-L)
GRIP(2SPEED) TRAVEL_SPEED_SW EP: 0.50 G/R BOOM-RAISE-SW 43 AUX2: 0.50 P SW1 SW2 AUX2: 0.50 O/B
Vcc(W) NB: 0.50 W/B 66 AUX2: 0.50 O/B 1 2
AUX2-SOL-FEEDBACK
1 AI: 0.30 B/R
PUSH_SW(B) NB: 0.50 Y/B MULTIPURPOSE-SW 16
2 74
AI: 0.30 O AI-CHANGE-SW EP-SOL EP: 0.50 G SOLENOID
3 75 22 SOLENOID(E/P) SOLENOID(E/P)
EP: 0.50 G/B EP: 0.50 G SW1 SW2 EP: 0.50 G/B
NB: 0.50 Y/B TRAVEL-SPEED-SW EP -SOL-FEEDBACK
GRIP(ANGLE_TILT) or_RD458-65751(Aside) .50 Y/B 57 21
1 2
TRAVEL_SPEED&ANGLE_BLADE_SW AUX2: AUX1: 0.30 L/W AB: 0
MULTIPURPOSE-LEVER-SW
Vcc(B) AB: 0.50 W/B
A-1
73
TRAVEL-SPEED-SOL BASE: 0.50 Y SOLENOID(TRAVEL_SPEED)
CRSD: 0.30 G/O DPF-INHIBIT-SW SOLENOID(TRAVEL_SPEED) SOLENOID(TRAVEL_SPEED)
PUSH_SW(W) AB: 0.50 Y/B 81
A-2 70 BASE: 0.50 Y (+) (-) BASE: 0.50 B
LEFT_SW_ON1(Y) AB: 0.50 R/Y AUX2: AUX1: 0.30 Y/R AUX1-HOLD-SW MULITIPURPOSE-SOL MF: 0.50 Y/B 1 2
A-3 69 17 SOLENOID(MULTI) GND3
RIGHT_SW_ON2(Y) AB: 0.50 L/Y AUX2: AUX1: 0.30 L
A-4
AUX2-HOLD-SW
ANGLE(R)-SOL AB: 0.50 G/W SOLENOID(MULTI) SOLENOID(MULTI)
DUMMY(W) 72 MF: 0.50 Y/B MF: 0.50 B
18 (+) (-)
B-1 AB: 0.50 L/Y ANGLE(R)-SW 1 2
COM(B) 71 ANGLE(l)-SOL AB: 0.50 R/B
SOLENOID(ANGLE-R) GND3
B-2 AB: 0.50 R/Y 20 SOLENOID(ANGLE-R)
DOWN_SW_ON4(Y) ANGLE(L)-SW SOLENOID(ANGLE-R)
B-3 68 ANTITHEFT-HORN-RELAY AT: 0.50 L/R AB: 0.50 G/W (+) (-) AB: 0.50 B
UP_SW_ON3(Y) BASE: 0.50 G/W LEVER-LOCK-SW 13 1 2
B-4 67 SOLENOID(ANGLE-L) GND3
ANGLE_SW LEVER-LOCK-SOL BASE: 0.50 G
SOLENOID(ANGLE-L) SOLENOID(ANGLE-L)
62
CHARGE-INPUT AB: 0.50 R/B (+) (-) AB: 0.50 B
1 2
SENSOR(PRESSURE,5MPA) TRAVEL-ALARM-BUZZER BASE: 0.50 B/Y
GND3
GND BASE: 0.50 B/Y
OIL-SW 14
1 BUZZER-OUT BASE: 0.50 Y/B
SENSOR Vout BASE: 0.50 L/B FUEL-SW 40
5MPA 2
Vcc(+5V) BASE: 0.50 R/B
3 TRAVEL_ALARM(FRONT,+)
TRAVEL_PRESSURE_SENSOR DISPLAY-CHANGE-SW BASE: 0.50 R/B 0.5R(+)
A-1 BUZZER,BACK
water-proof BASE: 0.50 B/Y 0.5B(-)
USER-CHANGE-SW
B-1
TRAVEL_ALARM(FRONT,GND)
BASE: 0.50 R/B +5V-OUT GLOW-RELAY CRSD: 0.50 B/R
11 33 TRAVEL_ALARM(REAR,+)
BASE: 0.50 R/B 0.5R(+)
HYDRAULIC TEMP. SENSOR BASE: 0.50 B/Y GND(Sensor-Use)
BACKETLOCK-SOL-RELAY A-1 BUZZER,BACK
10 BASE: 0.50 B/Y
OTS: 0.75 f L OTS: 0.75 f B/Y 15 0.5B(-)
1 2 FUEL-SENSOR B-1
EF-MODE-INDICATOR BASE: 0.30 L/W TRAVEL_ALARM(REAR,GND)
BASE: 0.50 L/B TRAVEL-PRESSURE-SENSOR
47
53 DPF-INHIBIT-INDICATOR CRSD: 0.30 G/B N_B
48 I:
WATER-TEMP-SENSOR 0.50
ANTITHEFT-FLASHER-LED AT: 0.30 R Y/R ELECTRICAL_BUZZER
OTS: 0.75 f L JOINT-BUZ AV0.5R(+)
OIL-TEMP-SENSOR 37 water-proof 1 BUZZER,BACK
36 BASE: 0.50 Y/B AV0.5B(-)
MULTI-PURPOSE-LED AI: 0.30 W
BOOM-ROD-PRESS-SENSOR 2
38
BOOM-BOT-PRESS-SENSOR AI-MODE-LED AI: 0.30 L/W
39
BOOM-POT
AI-SELFHOLD-RELAY BASE: 0.30 Y/G
12
AI: 0.30 R ACCEL-POT
7
AI-MOTOR-POT
ARM-POT
AUX2: AUX1: 0.30 W AUX1-POT1
ASSY_METER
28
LCD_METER
AUX1-POT2
BASE: 0.50 R +B
7
AUX2: AUX1: 0.30 W AUX2-POT1 BASE: 0.50 BR CAN(L)
29 5
BASE: 0.50 BR/W CAN(H)
AUX2-POT2
6
BASE: 0.50 R/W AC_SW
8
BASE: 0.50 L FUEL_SENSOR
ENGINE-REV-SIGNAL
1
WATER_TEMP_SENSOR
BASE: 0.50 B/W WAKEUP-SIGNAL 2
31 ANALOG_GND
AT: 0.50 W/B +12V-OUT
3
CN_VSS
41
4
BASE: 0.50 R/B AC-SW(KEY-SW) CRSD: 0.75 f L OLS_SW
W/B
76 9
N_BI: 0.50 Y/R +B(DIRECT)
BASE: 0.75 f W/R CHARGE_SW
10
59 BASE: 0.50 B/W
AUX2: AUX1: 0.30
WAKEUP_OUT
BASE: 2 f B GND(POWER) 11
2 BASE: 0.50 G REMOTE_WAKE_UP
GND1 12
13
BASE: 0.50 B GND
AI: 092 R/B 14
GND3
N_BI: 0.50 Y/R
SWITCH,DOWN (BLACK)
AT&N_BI: 0.30 Y/R LCD_METER_REMOTE_WAKEUP_SW LCD_METER_REMOTE_WAKEUP_SW
BASE: 0.50 G R G BASE: 0.50 B
AUX2: AUX1: 240 R/B
1 2
N_BI: 0.50 Y/R GND2
R/B
R/B
SWITCH,OIL
AI: 0.50 B/Y BASE: 0.50 R/W OIL-SW,D
R/B
CRSD: CRSB: 0.30
CRSD: CRSB: 0.30
R/B
R/B
R/B
R/B
R/B
CRSD: 0.75 f L
R/B
R/B
1
1.25
0.30
0.30
0.50
0.50
0.50
0.50
0.50
CRSD:
BASE:
BASE:
BASE:
BASE:
BASE:
AUX2: AUX1: 0.30 B/Y
AI:
AI:
FUSE(ECU-MAIN(AC)) FUSE(ECU-MAIN(AC)) FUSE(ECU-MAIN(AC))
SENSOR,FUEL
BASE: 3 R/W BASE: 0.50 R/B
5 SENSOR,FUEL SENSOR,FUEL
BASE: 0.50 L BASE: 0.50 B
MiniFuses FUEL_SENSOR
1
EARTH
2
R/B
RD451-54101 DUMMY GND3
3
FUSE(ECU-MAIN(+B)) FUSE(ECU-MAIN(+B)) FUSE(ECU-MAIN(+B))
0.30
N_BI: 5 R N_BI: 0.50 Y/R
5
MiniFuses
BCN:
CAN CAN
RD451-54101 5 5 BASE: 0.50 BR/W CAN(H)
1
8 8 BASE: 0.50 BR CAN(L)
2
6 6 CRSD: 0.50 BR/W
VALVE,ASSY(PL,R,AX) CRSD: 0.50 BR
JS_CONTROL(R) JS_CONTROL(R) 7 7
AUX2: AUX1: 0.30 R/B +5V(R) GND(B) AUX2: AUX1: 0.30 B/Y
1 2 1 1
OUTPUT(W) AUX2: AUX1: 0.30 W
8 3
FUSE(METER(+B)) FUSE(METER(+B)) FUSE(METER(+B)) AUX2: AUX1: 0.30 L Vcc_SW1(G) HORN_SW1(L) AUX2: AT&AUX1: 0.30 L/W
4 4
BASE: 5 R BASE: 0.50 R 7 4
10 AUX2: AUX1: 0.30 W/B Vcc_SW2(Gy) TRIG_SW2(Y) AUX2: AUX1: 0.30 Y/R 3 3
MiniFuses 5 6
2 2
RD451-54101 VALVE,ASSY(PL,L,AX)
AUX2: AUX1: 0.30 W/B
JS_CONTROL(L) JS_CONTROL(L) to_J/C(CAN,MAIN)
AUX2: AUX1: 0.30 B/Y J/C(CAN,MAIN)
AUX2: AUX1: 0.30 R/B +5V(R) GND(B)
1 2
RELAY(HORN)
OUTPUT(W) AUX2: AUX1: 0.30 W RELAY(HORN)
8 3 NULL
AUX2: AUX1: 0.30 W/B Vcc_SW1(G) PUSH_SW1(L) AUX2: AUX1: 0.30 L/W RELAY(HORN) 4
7 4 BASE: 0.50 L/W 30 87 BASE: 1.25 L
AUX2: AUX1: 0.30 W/B Vcc_SW2(Gy) TRIG_SW2(Y) AUX2: AUX1: 0.30 L 3 5
5 6 DIODE(7321-9822) AT: 0.50 L/R 86 85 BASE: 0.50 B
1 2
FUSE(HORN-SW) FUSE(HORN-SW) FUSE(HORN-SW) DIODE(ANTITHEFT_HORN_PROTECT) D_7321-9822 DIODE(ANTITHEFT_HORN_PROTECT) L/R GND2
AUX2: AUX1: 5 R AUX2: AUX1: 0.30 L AUX2: AT&AUX1: 0.30 L/W A C AT: 0.50 L/R 0
5 0.5 BASE: 0.50 L HORN(+) ASSY_HORN
2 400V 1 AT: BASE: 1.25 L
MiniFuses A-1
T1
FUSE(HORN-MAIN) FUSE(HORN-MAIN) FUSE(HORN-MAIN) DIODE(7321-9822) BASE: 1.25 B T2
B-1
BASE: 5 R BASE: 059 L/W DIODE(HORN) D_7321-9822 DIODE(HORN)
HORN(-)
10 BASE: 0.50 L C A BASE: 0.50 B
MiniFuses 1 400V 2
GND2
L
RD451-54101
R/W
BASE: 0.50
RELAY(LIGHT)
OFF ON
BASE: 0.30
RELAY(LIGHT)
SWITCH(WORKLIGHT) NULL LIGHT,WORK
FUSE(RELAY) FUSE(RELAY) FUSE(RELAY) WORKLIGHT_SWITCH RELAY(LIGHT) 4 FUSE(FRONT-WORKLIGHT) FUSE(FRONT-WORKLIGHT) FUSE(FRONT-WORKLIGHT) to_WORKLIGHT to_MAIN(WORKLIGHT) to_MAIN(WORKLIGHT) to_WORKLIGHT
BASE: 3 R/W BASE: 0.50 L BASE: 0.50 L Vcc BASE: 3 R 30 87 BASE: 3 Y BASE: 3 Y BASE: 1.25 Y BASE: 1.25 Y CA_R(+) CB_B(-) BASE: 1.25 B BASE: 1.25 B
5 7 WORKLIGHT_SWITCH 3 5 15 W/H00 1 1 W/H12 1 2 W/H12 2 2 W/H00
OFF BASE: 0.30 R 86 85 BASE: 0.50 B FRONT_WORKLIGHT(+) FRONT_WORKLIGHT(-) GND2
MiniFuses MiniFuses
L
9 1 2
RD451-54101 ON BASE: 0.30 R GND2 RD451-54101
BCN: 0.50
6 W/H12 W/H(FRONT)
R/W
8 FUSE(CAB-WORKLIGHT) FUSE(CAB-WORKLIGHT) FUSE(CAB-WORKLIGHT)
BASE: 3 Y BASE: 2 f Y
20
HT: AC: 0.30
2 MiniFuses
BASE: 0.50 L LED(+) LED(GND) BASE: 0.30 B RD451-54101
4 10
GND1
1 5
LIGHT,WORK
CANOPY_WORKLIGHT,L(+) CANOPY_WORKLIGHT,L(-)
BASE: 1.25 R CA_R/B(+) CB_B(-) BASE: 1.25 B
1 2
SUB_WORK_LIGHT to_MAIN(SUB_WORK_LIGHT)
CNP: 1.25 Y CNP: 1.25 Y BASE: 1.25 R LIGHT,WORK to_MAIN(SUB_WORK_LIGHT) SUB_WORK_LIGHT
CANOPY_WORKLIGHT,R(+) CANOPY_WORKLIGHT,R(-)
W/H00 1 1 W/H23 BASE: 1.25 B CNP: 1.25 B
CA_R/B(+) CB_B(-) 1 1
1 2 W/H23 W/H00 GND2
W/H23 W/H(CANOPY_WORK_LIGHT(4P))
RELAY(BEACON)
RELAY(BEACON) LIGHT,WORK
NULL W/H00 W/H19 CAB_WORKLIGHT,FR CAB_WORKLIGHT,FR
FUSE(BEACON) FUSE(BEACON) FUSE(BEACON) RELAY(BEACON) 4 BASE: 2 f Y BASE: 0.85 R BASE: 0.85 R CA_R(+) CB_B(-) BASE: 0.85 B
BCN: 5 R BCN: 1.25 W BCN: 1.25 W 30 87 BCN: 1.25 BR 4 4 to_MAIN(CAB) A-1 B-1
15 CAB
3 5 LIGHT,WORK RADIO
R
BCN: 0.30 R/B 86 85 BCN: 0.30 R/Y BASE: 0.50 O
MiniFuses 1 2 CAB_WORKLIGHT,FL CAB_WORKLIGHT,FL RADIO(+B)
RADIO(+B)
1
BASE: 0.85
RD451-54101 BASE: 0.85 R CA_R(+) CB_B(-) BASE: 0.85 B BASE: 1.25 Y RADIO(AC)
A-1 B-1 SPEAKER,ASSY RADIO(AC) 2
LIGHT,WORK SPEAKER(R) BASE: 0.50 B
RADIO(GND)
RADIO(GND)
3
OFF ON CAB_WORKLIGHT,B CAB_WORKLIGHT,B BASE: 0.50 W/B
SWITCH(BEACON) BASE: 0.85 R CA_R(+) CB_B(-) BASE: 0.85 B
(-)
1
BASE: 1.25 B
RADIOFRAME(GND)
RADIOFRAME(GND)
4
BEACON_SWITCH BASE: 0.50 W
A-1 B-1 (+) BASE: 0.50 W SPEAKER(R+)
BCN: 0.30 R/Y Vcc SPEAKER(R-)
7 BEACON_SWITCH LAMP(BEACON) 2
BASE: 0.50 W/B
5
SPEAKER(R-)
OFF W/H00 W/H19 BEACON BEACON SPEAKER(R-)
9 BCN: 1.25 BR BASE: 1.25 BR BASE: 1.25 BR M5 M5 BASE: 0.85 B SPEAKER,ASSY BASE: 0.50 Y
6
ON BCN: 0.50 B CAB
8 8 to_MAIN(CAB) 1 M 2 SPEAKER(L) SPEAKER(L+)
SPEAKER(L+)
7 CAB_POWER_SOURCE
O
6 (-) BASE: 0.50 Y/B BASE: 0.50 Y/B SPEAKER(L-)
GND3
BR
ASSY_LIGHT,ROOM 1 SPEAKER(L-) 8 GND(RADIO)
BASE: 0.50 Y
BASE: 0.50
8 ROOM_LIGHT (+) BASE: 1.25 B 1
W/H00 W/H19 ROOM_LIGHT
BASE: 1.25
2
3 BASE: 0.50 O BASE: 0.50 O com DOOR GND(RADIO,CAB) 2
3 3 to_MAIN(CAB) 2 1 BASE: 0.50 O ROOM_LIGHT(+B)
CAB
2 ON BASE: 1.25 B 3
O
BCN: 0.50 L LED(+) LED(GND) BCN: 0.30 B 3 BASE: 0.85 R CAB_WORK_LIGHT
4 10 4
GND1
BASE: 0.50
BASE: 3.00 B GND(CAB)
1 5 5
FUSE(ROOM_LIGHT) FUSE(ROOM_LIGHT) FUSE(ROOM_LIGHT)
B
N_BI: 5 R BASE: 0.50 O
B
6
5 BASE: 1.25 Y RADIO(AC)
BASE: 0.85
BASE: 0.85
BASE: 0.85
BASE: 1.25
BASE: 0.50
MiniFuses 7
W/H00 W/H19 BASE: 1.25 BR BEACON
W/H00 W/H19 8
FUSE(RADIO(AC)) FUSE(RADIO(AC)) FUSE(RADIO(AC)) CNP: 1.25
G W/H00 W/H19 BASE: 1.25 Y BASE: 3 B CAB_POWER_SOURCE
CAB: 3 W CAB: 1.25 Y CAB: 1.25 Y BASE: 1.25 Y
15 CAB
7 7 to_MAIN(CAB) GND(CABFRAME)
BASE: 3 B BASE: 3.00 B
MiniFuses 5 5 to_MAIN(CAB)
GND2 BASE: 0.85 B CAB
BASE: 1.25 B
1 1 to_MAIN(CAB) BASE: 0.85 G BASE: 0.75 G
B
FUSE(WIPER/WASHER) FUSE(WIPER/WASHER) FUSE(WIPER/WASHER) GND(RADIO) CAB
to_WIPER 2 2 to_CAB(WIPER) 1
(+B)
MOTOR_WIPER
CAB: 1.25 G/W
BASE: 0.50
CAB: 3 W CAB: 1.25 G/W BASE: 0.85 G BASE: 0.75 R (S)
15 CAB(WIPER) 3 3 to_MAIN(CAB_WIPER) 4 WIPER,F
CAB: 1.25 R/W BASE: 0.85 W BASE: 0.85 W BASE: 0.75 W M BASE: 0.75 B
MiniFuses CAB(WIPER) 1 1 to_MAIN(CAB_WIPER) to_WIPER 4 4 to_CAB(WIPER) 3
(+1) (-)
2
WASH2
WASH1
SWITCH,ASSY(WIPER)
OFF
RD451-54101
ON
CAB: 1.25 L/W BASE: 0.85 R BASE: 0.85 R WIPER,F
2 2 to_MAIN(CAB_WIPER) to_WIPER 3 3 to_CAB(WIPER)
CAB(WIPER) TANK(WASHER) BASE: 1.25 B
WIPER_SWITCH WASHER_TANK WASHER_TANK BASE: 0.85 B BASE: 0.75 B
CAB: 1.25 W CAB: 1.25 W BASE: 0.50 W BASE: 0.50 W (+) (-) BASE: 0.50 B 1 1 to_CAB(WIPER)
WASHER(B)
3 CAB(WIPER) 4 4 to_MAIN(CAB_WIPER) 2 M 1
to_WIPER
W/H19 W/H20 GND(WIPER,F)
Vcc_wash(Y/B) CAB: 1.25 G/W W/H00 W/H19 W/H19 W/H20
2 W/H00 W/H19 W/H19 W/H20
Vcc(R)
1
CAB: 1.25 G/W W/H00
W/H00
W/H19
W/H19
W/H19 W/H,CAB W/H19 W/H20
W/H20 W/H,WIPERCODE
mo(+1)(G/R) CAB: 1.25 R/W
6
S(G/W) CAB: 1.25 L/W
5
Null SERVO_MOTOR SERVO_MOTOR
4 ASSY_SWITCH,AIR-CON HT: AC: 0.50 W BASE: 0.50 W MAXCOOL
M
A/C_HEATER_CONTROLER 7 7 to_MAIN(W/H_HEATER_CONTROLER) 1
HT: AC: 0.50 Y BASE: 0.50 Y MAXHOT
A/C_HEATER_CONTROLER 8 8 to_MAIN(W/H_HEATER_CONTROLER) 2
A/C_HEATER_CONTROLER IN CONSTANT OUT A/C_HEATER_CONTROLER
HT: AC: 0.50 BR/W BASE: 0.50 BR/W Pt
VOLTAGE A/C_SW A/C_HEATER_CONTROLER 2 2 to_MAIN(W/H_HEATER_CONTROLER) 3
HT: AC: 0.50 R +B CIRCUIT POT_Vcc HT: AC: 0.50 R/Y null
FUSE(A/C_CONTROLLER) FUSE(A/C_CONTROLLER) FUSE(A/C_CONTROLLER)
16 2 4
HT: AC: 5 R/Y HT: AC: 0.50 R HT: AC: 0.50 W/R IG POT_Vout HT: AC: 0.50 BR/W HT: AC: 0.50 R/Y BASE: 0.50 R/Y GND
5 8 1 A/C_HEATER_CONTROLER 3 3 to_MAIN(W/H_HEATER_CONTROLER) 5
W/R
HT: AC: 0.50 W/R null
MiniFuses 7 CPU
POT_GND
3 6 A/C_FAN_SWITCH
HT: AC: 0.50 W/R BASE: 0.50 W/R Vz
FUSE(BLOWER) FUSE(BLOWER) FUSE(BLOWER)
RELAY(20A,MICRO-ISO) A/C_HEATER_CONTROLER 4 4 to_MAIN(W/H_HEATER_CONTROLER) 7
HT: AC: 0.50
14 12
HT: AC: 5 R/Y HT: AC: 3 R AC: 0.50 G/B THERMO_SW
HOT_OUT SERVO_OUT2:HOT HT: AC: 0.50 Y OFF Lo Mi Hi
30 RELAY(BLOWER) 11 6 W/H00 W/H06
Null HT: AC: 0.50 L HOT_IN COOL_IN HT: AC: 0.50 W A/C_FAN_SWITCH
MiniFuses RELAY(BLOWER) 4 10
FAN
MOTOR
COOL_OUT SERVO_OUT1:COOL
5
W/H00
W/H00
W/H06
W/H06 HT: AC: 3 B com
HT: A
HT: AC: 3 R 30 87 HT: AC: 3 L/W DRIVE ILL(-) HT: AC: 0.50 B W/H00 W/H06 0.50 C: 3
FUSE(COMPRESSOR) FUSE(COMPRESSOR) FUSE(COMPRESSOR)
3 5 13 9 W/H00 W/H06 HT: AC: 0.50 L HT: A L P-ON
CIRCUIT
HT: AC: 3 W HT: AC: 0.85 W/R HT: AC: 0.85 W/R 86 85 HT: AC: 0.50 L
COMPRESSOR_ASSY HT: AC: 0.30 R/W ILL(+) GND HT: AC: 0.50 B GND1 C: 0
.50 L 6
10 1 2 15 4 HT: AC: 0.50 L LO
COMPRESSOR_CLUTCH(A/C) RD451-93901 GND1 W/H06 W/H,BLOWERMOTOR,AC 2
MiniFuses
Y
AC: 1.25 f Y
W/R
HT: AC:3 L/Y MID
RD451-54101 RELAY(20A,MICRO-ISO) 1 1
AC: 0.50
HT: AC:3 L/B HI
RELAY(COMPRESSOR)
DIODE(6098-0061) 4
AC: 0.85
Null HT: AC: 3 B
RELAY(COMPRESSOR) 4 DIODE(COMPRESSOR) D_6098-0061 DIODE(COMPRESSOR) 5
AC: 0.85 W/R 30 87 AC: 1.25 f Y AC: 0.50 Y C A AC: 0.50 B GND1
AC: 0.85 W/R
3
86 85
5
AC: 0.50 G/R
1 2
GND2 THERMOSTAT HT: AC: 3 B
THERMOSTAT
1 2
DUAL_PRESSURE_SWITCH W/H00 W/H06 GND1
AC: 0.85 W/R BASE: 0.85 W/R A/C THERMISTOR
DUAL_PRESSURE_SWITCH DUAL_PRESSURE_SWITCH A/C_HEATER_CONTROLER 1 1 to_MAIN(W/H_HEATER_CONTROLER) 2 6
AC: 299 G/R AC: 0.50 G AC: 0.50 G BASE: 0.50 G MGC THERMISTOR
THERMISTOR
1 2 A/C_HEATER_CONTROLER 6 6 to_MAIN(W/H_HEATER_CONTROLER) 3 7
W/H00 W/H06 Null GND
FUSE(ELECTRICAL_OUTLET) 4 1 2
AC: 0.50 G/B BASE: 0.50 G/B GND Null W/H06 W/H00
CigaretteSocket A/C_HEATER_CONTROLER 5 5 to_MAIN(W/H_HEATER_CONTROLER) 1 5 W/H06 W/H00
G W/H06 W/H00
FUSE(ELECTRICAL_OUTLET) FUSE(ELECTRICAL_OUTLET) : 1.25 ELECTRICAL_OUTLET W/H00 W/H06 THERMOSTAT
BASE: 3 L/B HT: AC: 3 L/B
BASE: 3 W CNP BASE: 1.25 G BASE: 1.25 G 2 2 A/C_HEATER_POWER1
15
(+) (+) to_MAIN(A/C_HEATER_POWER1)
1 BASE: 3 L/Y HT: AC: 3 L/Y
MiniFuses BASE: 2 B (-) GND to_MAIN(A/C_HEATER_POWER1)
BASE: 3 B
1 1 A/C_HEATER_POWER1
2 HT: AC: 3 B
RD451-54101 GND2 to_MAIN(A/C_HEATER_POWER1) 3 3 A/C_HEATER_POWER1
ASSY_PUMP,FUEL_BOOT RESISTOR_BLOWER
RESISTOR_BLOWER
FUSE(FUEL_PUMP) FUSE(FUEL_PUMP) FUSE(FUEL_PUMP) FUEL_PUMP BASE: 3 L/Y M1
BASE: 3 R/W BASE: 0.50 Y/R BASE: 0.50 Y/R + 1 221 ℃± 10 ℃
5 1 BASE: 3 L/B BASE: 3 L/B HI
BASE: 0.50 B 2
MiniFuses 2
-
BASE: 3 B LO
RD451-54101 GND1 3
M2
4
FUSE(HEATER,FUELFILTER) FUSE(HEATER,FUELFILTER) FUSE(HEATER,FUELFILTER) HEATER(FUEL_FILTER) HEATER(FUEL_FILTER) HEATER(FUEL_FILTER)
CRSD: 3 W CRSD: 1.25 W W W/B CRSD: 1.25 B
20 1 2 BLOWER_MOTOR
GND2
MiniFuses BLOWER_MOTOR BLOWER_MOTOR
RD451-54101 HT: AC: 3 L/W BASE: 3 L/W BLOWER
M BLOWER BASE: 3 L/B
A/C_HEATER_POWER2 1 1 to_MAIN(A/C_HEATER_POWER2) 1 2
W/H00 W/H06
W/H06 W/H,BLOWERMOTOR,AC
RELAY(CRS_MAIN)
RELAY(CRS_MAIN)
NULL
RELAY(CRS_MAIN) 4
CRSD: 3.00 R 30 87 CRSD: 3.00 R
3 5
CRSD: 2 f R 86 85 CRSD: 0.50 L
1 2
REGISTER(120ohm) REGISTER(120ohm) REGISTER(120ohm)
SHIELD-NE,D
CRSD: 0.50 Y REGISTER REGISTER CRSD: 0.50 G water-proof
2 120ohm 120ohm 1 SENSOR(NE)
ENGINE-ECU(SS2intT4) CRSD: 0.50 B S CRANKSHAFT_SENSOR(NE),D CRANKSHAFT_SENSOR(NE),D
f R
NE_Vcc CRSD:0.75 f G 5 CRSD: 0.75 f G Vcc OUT CRSD: 0.75 f R
A-22 1 3
R
CRS-ECU(DENSO,58pin) NE_GND CRSD:0.75 f B CRSD: 0.75 f B GND
CRSD: 0.75
A-19 2
CRSD: 0.50
CRSD: 0.50
CRSD: 0.30
CRSD: 2 f R +BP NE_SIG CRSD:0.75 f R
J/C(CAN,EGR,SERVICE) CRSD: 2 f R
B-5
+BP
A-43 SENSOR(G)
B-6 CAMSHAFT_SENSOR(G),D CAMSHAFT_SENSOR(G),D
to_J/C(CAN,EGR,SERVICE) JOINT-CRS_POWER,D G_Vcc CRSD: 0.75 f G CRSD: 0.75 f G BASE: 0.75 f G BASE: 0.75 f G VCC OUT BASE: 0.75 f Y
4
water-proof A-44 to_CAMSHAFT_SENSOR 3 3 to_MAIN(CAMSHAFT_SENSOR) 1 3
G
G
Y
G_GND CRSD: 0.75 f Y CRSD: 0.75 f Y BASE: 0.75 f L BASE: 0.75 f L GND
CRSD: 0.50 Y CRSD: 0.50 Y A-18 to_CAMSHAFT_SENSOR 2 2 to_MAIN(CAMSHAFT_SENSOR) 2
f
f
CRSD: 0.50
CRSD: 0.50
SERVICE_TOOL 1 1 SERVICE_TOOL(CAP) G_SIG CRSD: 0.75 f L CRSD: 0.75 f L BASE: 0.75 f Y
to_CAMSHAFT_SENSOR 1 1 to_MAIN(CAMSHAFT_SENSOR)
0.75
0.75
CRSD: 0.50 G CRSD: 0.50 G A-42
SERVICE_TOOL 3 3 SERVICE_TOOL(CAP) CRSD: 0.50 B S 6 CRSD: 0.75 f B BASE: 0.75 f B 7 S
CRSD: 0.50 B
water-proof to_CAMSHAFT_SENSOR 4 4 to_MAIN(CAMSHAFT_SENSOR)
CRSD:
CRSD:
SERVICE_TOOL 4 4 SERVICE_TOOL(CAP) W/H00 W/H11
GND1 SHIELD-G1,D GND3 W/H00 W/H11
water-proof
W/H11 W/H,GS
SHIELD-G2,D
CRS-ECU(DENSO,96pin) W/H00 W/H11
W/H00 W/H11
CRSD: 0.50 R/B
SERVICE_TOOL 2 2 SERVICE_TOOL(CAP)
EngineWarning_Lamp
VALVE,ASSY(EGR)
EngineStop_Lamp
EGR_VALVE,D
CRSD: 0.75 f Y CAN_H CRSD: 0.50 L MainRelay OIL_Lamp
MicroComputer
1 B-33
CRSD: 0.75 f G CAN_L Heater_Lamp
2 M
CRSD: 0.75 f B GND OverHeat_Lamp to_J/C-SLD-GND,D 5 5
3
GND2 CRSD: 0.75 f R POWER(12V) ForceRegenReq_Lamp to_J/C-SLD-GND,D 3 3
4
Regen_Lamp to_J/C-SLD-GND,D 6 6
CRSD: 0.50 B
CRSD: 0.50 Y CAN1-H to_J/C-SLD-GND,D 2 2 1 1 to_J/C-SLD-GND,D
B-51
J/C-SLD-GND,D
GND3
CRSD: 0.50 G CAN1-L CRS-ECU(DENSO,96pin)
CRS-ECU(DENSO,58pin) B-52
AccelSensor1_Vcc
AccelSensor1_SIG
SENSOR
CRS-ECU(DENSO,58pin) DPF_DIFF_PRESSURE_SENSOR,D
CRSD: 0.50 Y CAN2-H AccelSensor1_GND CRSD: 0.75 f L/R VDD
B-38 3 10mA
CRSD: 0.50 G CRSD: 0.75 f L/B
CAN2-L
CRS-ECU(DENSO,96pin)
GND
ASIC
B-39
AccelSensor2_Vcc CRSD: 0.75 f L
2
VOUT
4.7ohm
1
SENSOR_AIR_FLOW AccelSensor2_SIG
AIR_FLOW_SENSOR,D TAC AccelSensor2_GND
PUMP_ASSY_SUPPLY
- CRSD: 0.5 f GR SUCTION_CONTROL_VALVE,B
CRS-ECU(DENSO,58pin)
1 EGR_Lft_SEN_Vcc CRSD: 0.75 f G SCV
+ CRSD: 0.5 f L A-1 SUPPLY
2
CRSD: 0.5 f W/R
EGR_Lft_SEN_GND VehicleSpeed CRSD: 0.75 f B/R +B CONTROL
VC A-2
AIR 3 EGR_lIFT_SEN VALVE
FLOW GND CRSD: 0.5 f W/B FUEL_TEMP_SENSOR
SENSOR 4 EGR_Motor(-) PressDiffSensor_SIG CRSD: 0.75 f L CRSD: 0.75 f G
POWER CRSD: 0.50 R A-66 B-1
5 EGR_Motor(+) PressDiffSensor_GND CRSD: 0.75 f L/B CRSD: 0.75 f G/W
A-59 B-2
PressDiffSensor_Vcc CRSD: 0.75 f L/R
A-23
CRSD: 0.5 f W/R MAF_SEN_SIG CRS-ECU(DENSO,96pin) SENSOR,WATER_TEMP.
WATER_TEMP_SENSOR,D WATER_TEMP_SENSOR,D
THROTTLE_VALVE_ASSY(INTAKE) CRSD: 0.5 f W/B
A-30
MAF_GND SCV(+) CRSD: 0.75 f B/R CRSD: 0.75 f L/R GND CRSD: 0.75 f L
INTAKE_THROTTLE_MOTOR,D A-7 B-20 1 2
M1(OPEN) CRSD: 0.75 f B/R CRSD: 0.5 f L IntakeAirTemp(AFS) SCV(-) CRSD: 0.75 f G
M 1 A-34 B-7 CRS-ECU(DENSO,58pin)
M2(CLOSE) CRSD: 0.75 f R/B CRSD: 0.5 f GR IntakeAirTemp(AFS)_GND
RAIL_ASSY_COMMON
2 CRS-ECU(DENSO,96pin) A-10
GND CRSD: 0.75 f L/B FuelTemp_SIG CRSD: 0.75 f G RAIL_PRESSURE_SENSOR,D
3 A-31 CRSD: 0.5 f L A-VCC
Hall IC
TPS CRSD: 0.75 f L CRSD: 0.75 f R/B IntakeThrottleMotor(+) FuelTemp_GND CRSD: 0.75 f G/W 1 Pressure
4 B-57 A-8 CRSD: 0.5 f Y
5V CRSD: 0.75 f G/W CRSD: 0.75 f B/R IntakeThrottleMotor(-) CoolantTemp_SIG CRSD: 0.75 f L/R 2
PFUEL
Sensor
5 CRS-ECU(DENSO,58pin) B-44 A-39 CRSD: 0.5 f G A-GND
CRS-ECU(DENSO,96pin) CoolantTemp_GND CRSD: 0.75 f L 3
6 A-79 A-15
CRSD: 0.75 f L IntakeThrottleSensor_SIG
L/B B-29
CRSD: 0.75 f IntakeThrottleSensor_GND SLD_GND CRS-ECU(DENSO,96pin)
B-16
CRSD: 0.75 f G/W IntakeThrottleSensor_Vcc
CRS-ECU(DENSO,58pin) B-9
CRSD: 0.5 f Y water-proof
CRS-ECU(DENSO,96pin)
PFuel_SIG
A-40 JOINT-RPS CRSD: 0.50 B S SHIELD-RAIL
water-proof
PFuel_SIG CRSD: 0.5 f Y 8
A-41
PFuel_Vcc CRSD: 0.5 f L
CRS-ECU(DENSO,58pin)
A-24
PFuel_GND CRSD: 0.5 f G
A-16
ExtShutterPull_Relay BoostSEN_Vcc
ExtShutterHold_Relay BoostSEN_SIG
CRS-ECU(DENSO,96pin)
BoostSEN_GND
Starter_Relay
ExtAirTempSEN_SIG
B-28
CRSD: 0.50 Y/B ST_SW ExtAirTempSEN_GND
B-54 B-15 CRS-ECU(DENSO,58pin)
IG_SW
CRS-ECU(DENSO,96pin)
IG_SW
CRS-ECU(DENSO,58pin)
CRS-ECU(DENSO,58pin)
STOP_SW
Parking_SW
ForceRegen_SW
Heater_Relay Regenlnhibit_SW
SWITCH(WATER_LEVEL)
J/C-INJ-GND,D
CRSD: 0.50 B WaterLevel_SW CRSD: 0.30 W
5 5 6 6 A-85 SWITCH(WATER_LEVEL) SWITCH(WATER_LEVEL)
to_J/C-INJ-GND,D CRS-ECU(DENSO,96pin)
to_J/C-INJ-GND,D
GND1 CRS-ECU(DENSO,96pin) FilterPlugged_SW CRSD: 0.30 W W W/B CRSD: 0.30 R
to_J/C-INJ-GND,D 4 4 CRS-ECU(DENSO,58pin) 1 2
CRSD: 1.25 f B/W INJ_Common1 CAN_SEL_SW
to_J/C-INJ-GND,D 3 3 A-49
CRSD: 1.25 f R/W INJ_Common1 BGmode_SW
2 2 CRS-ECU(DENSO,96pin)
to_J/C-INJ-GND,D A-73
CRSD: 1.25 f L/R INJ-Common2 RatedSpeedSel_SW(BG)
JOINT-INJ_012,D A-1
water-proof CRSD: 1.25 f B/R INJ-Common2 Neutral_SW
A-25
INJECTOR,ASSY SHIELD-01
water-proof S CRSD: 0.50 B JOINT-INJ_011,D CRSD: 1.25 f Y INJ_DRV_TWV1 OIL_SW
CRS-ECU(DENSO,58pin)
INJECTOR_1,D INJECTOR_1,D 1 water-proof A-74
CRSD: 2.0 f B 2 1 CRSD: 2.0 f W CRS-ECU(DENSO,96pin)
2 1 JOINT-INJ_022,D
water-proof CRSD: 1.25 f W/B INJ4_DRV_TWV4 Inlet_DOC_Temp CRSD: 0.75 f LG
A-3 A-38
INJECTOR,ASSY SHIELD-02
water-proof S CRSD: 0.50 B JOINT-INJ_021,D Inlet_DOC_Temp_GND CRSD: 0.75 f L/B
INJECTOR_2,D INJECTOR_2,D 2 water-proof A-14
CRSD: 2.0 f B 2 1 CRSD: 2.0 f W CRSD: 1.25 f Y/B INJ2_DRV_TWV2 Outlet_DOC_Temp CRSD: 0.75 f B/R SENSOR(THERMO,0)
2 1 A-26 A-36 DOC_INLET_TEMP_SENSOR,D DOC_INLET_TEMP_SENSOR,D
JOINT-INJ_032.D
water-proof Outlet_DOC_Temp_GND CRSD: 0.75 f L CRSD: 0.75 f L/B CRSD: 0.75 f LG
A-12 1 2
INJECTOR,ASSY SHIELD-03
water-proof
3
S CRSD: 0.50 B JOINT-INJ_031,D CRSD: 1.25 f R/L INJ3_DRV_TWV3 Outlet_DPF_Temp CRSD: 0.75 f R/B
INJECTOR_3,D INJECTOR_3,D water-proof A-51 A-62
CRSD: 2.0 f B 2 1 CRSD: 2.0 f W Outlet_DPF_Temp_GND CRSD: 0.75 f L/R SENSOR(THERMO,1)
2 1 JOINT-INJ_042,D A-58 DOC_OUTLET_TEMP_SENSOR,D DOC_OUTLET_TEMP_SENSOR,D
water-proof CRSD: 2 f B POWER_GND CRSD: 0.75 f L CRSD: 0.75 f B/R
B-3 1 2
INJECTOR,ASSY SHIELD-04
water-proof
4
S CRSD: 0.50 B JOINT-INJ_041,D CRSD: 2 f B POWER_GND SIGNAL_GND CRSD: 2 f B
INJECTOR_4,D INJECTOR_4,D water-proof B-4 B-1
CRSD: 2.0 f B 2 1 CRSD: 2.0 f W GND1 CRSD: 0.85 B CASE_GND SIGNAL_GND CRSD: 2 f B SENSOR(THERMO,2)
2 1 B-18 B-2 DPF_OUTLET_TEMP_SENSOR,D DPF_OUTLET_TEMP_SENSOR,D
GND1 CRS-ECU(DENSO,58pin) CRS-ECU(DENSO,58pin) GND2 CRSD: 0.75 f L/R CRSD: 0.75 f R/B
GND1 GND2 1 2
Electrical Circuit Diagram (KX057-4 US, CA)
KiSC issued 04, 2021 A
CAB_ GND
232C A/C_HEATER_POWER2 ANGLE_SW BLOWER_MOTOR CANOPY_WORKLIGHT,R(-) DPF_DIFF_PRESSURE_SENSOR,D FRONT_ FUSE FUSE(HORN-
WORKLIGHT, (CABFRAME)
WORKLIGHT(+) (COMPRESSOR) MAIN)
FL
2 1 2 1 1 3 2 1
1 1 2 1 2 1 2 1 1
4 3 1
3 4 M8
C_OF02_6098- C_WF03_1813271-1_1
C_OF02_M C_OF02_M
C_WF01_6189-0 0325_1
C_WF04_7123-7740-40_1 iniFuses iniFuses
145_1 C_CAM01_1
C_WM04_6187-4441 _1 _1
_1 C_CBF01_ *1 279
1 DPF_OUTLET_TEMP_SENSOR,D C_CBF01_ *2 351 C_LAF01
1 _M8_1
A/C_FAN_SWITCH to_MAIN(A/C_HEATER BOOM_RAISE_SW COMPRESSOR_CLUTCH(A/C) FUSE
_POWER2) ANTITHEFT_ANTENNA CAB_ 2 1 (HORN-SW)
WORKLIGHT, FUSE(CRANE)
1 FL 1 FRONT_ GND(RADIO)
C_WF02_7283-7023_1 WORKLIGHT(-) 2 1
1 2
3 2 1 1 2 3 1 C_WF01_FW-C-1F_1 2 1
6 5 4 C_OF02_M 1
4 5 6 C_WF02_6189- DUAL_PRESSURE_SWITCH 1 iniFuses
C_WM01_6188-0 0156_1 C_OF02_M M8
_1
083_1
C_OF06_7123-2865-70_1 CRANKSHAFT_SENSOR(NE),D iniFuses
C_WM06_6189-6171 _1
_1
C_CAM01_ 2 1
1
CAB C_CAM01_ C_LAF01
AIR_FLOW_SENSOR,D 3 2 1 1 _M8_1
C_WF02_6189-0094_1 FUSE(LEVER_
FUSE(ECU-
4 3 2 1 CAB_ MAIN(+B)) LOCK)
A/C_HEATER_CONTROLER BATTERY(POWER),N_BI C_WF03_7283-8852-30_1
WORKLIGHT,FR
5 4 3 2 1 8 7 6 5 E/F_CHANGE_SWITCH FUEL_PUMP 2 1 GND(RADIO,
1 CRS-ECU(DENSO,58pin)
2 1 CAB)
C_WF05_6189-1 1 C_OF08_7123-
4 3 2 1 046_1 6083-30_1 4 3 2 1 C_OF02_M 1
1 C_OF02_M iniFuses
8 7 6 5 C_OM01_7122-4113 1 2 7 8 9 10 11 12 13 14 15 16 17 18 19 10 9 8 7 6 5 iniFuses _1
-30_1 2 _1
M5
C_CBF01_
20 21 22 23 24 25 26 27 28 29 30 31 32
AI_CONSOLE
C_WF08_7283-1081-40_1 to_MAIN(CAB) 1 C_OF10_7123-8307_1
3 4 C_OF02_7 FUSE(METER
MAIN(POWER),N_BI 123-2820 C_LEF01
4 3 2 1 _1 FUSE(ECU- (+B))
33 34 35 36 37 38 39 40 41 42 43 44 45 _M5_1
1 2 3 4 CAB_ MAIN(+B)),BI
8 7 6 5 WORKLIGHT,FR 5 6 46 47 48 49 50 51 52 53 54 55 56 57 58 2 1
1 ECU(MAIN)
5 6 7 8
to_MAIN(W/H_HEATER_ FUEL_TEMP 2 1
C_WF08_FW-C-8 GND(WIPER,F)
CONTROLER) 1 C_WF58_9-1452415-9_1 _SENSOR C_OF02_M
F_1 C_OF01_7123-4113
C_OM08_7122- iniFuses
-30_1 C_OF02_M
6083-30_1 _1
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 5 4 1
1 2 3 4 2 1 iniFuses
CRS-ECU(DENSO,96pin) 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 _1
AI_PRESSURE_SW M8
5 6 7 8 CAB(WIPER) C_CAM01_
C_WF02_1
BATTERY_TERMINAL,BI 1 3 FUSE(RADIO
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 78392-6_
1 2 3 4 5 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 1 FUSE(ECU- (AC))
1 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 MAIN(AC))
C_WM08_7282-1081-40_1 1 2 1 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 2 1 2 1
C_LAF01
2 CAMSHAFT_ 25 26 27 28 29 _M8_1
M8 4 3 SENSOR(G),D
FUSE(A/C_ 2 1 C_OF02_M
C_WF02_6189-0 49 50 51 52 53 C_WF81_1473244-1_1
54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 CONTROLLER) iniFuses
156_1 C_OF04_7123-
A/C_HEATER_CONTROLER 6040_1 _1
C_LAF01_M8_1 3 2 1 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 C_OF02_M
2 1 iniFuses
GND1
_1
C_WF03_6 FUSE(RELAY)
ALTERNATOR(+B) C_WF96_9-1452423-9_1
to_MAIN(CAB_WIPER) 189-1130 C_OF02_M 1
1 2 3 4 5 6 7 8 BATTERY_TERMINAL,N_BI _1 iniFuses
FUSE(ECU_
1 EGR_VALVE,D _1
M8
9 10 11 12 13 14 15 16 DIODE(COMPRESSOR)
MAIN(POWER)) 2 1
1 1 2
M6 CAN
C_OF16_MX34016SF1_1 3 4 4 3 2 1 C_OF02_M
M8
2 1 2 1 iniFuses C_LAF01
FUSE _1 _7009-1
2 1 C_WF04_6195-0030_1
836_1
C_LAF01_M6_1 C_OM04_7122- (ALTERNATOR)
C_OF02_6098-0017_1 C_OF02_M
C_LAF01_M8_1 6040_1
iniFuses
C_WF02_7 FUSE(ROOM_
123-8520 ELECTRICAL_BUZZER
2 1 _1
LIGHT)
CAB_POWER_ -40_1
ALTERNATOR(IG,L) DOC_INLET_TEMP_SENSOR,D
BEACON SOURCE C_OF02_M FUSE
1 iniFuses
(ELECTRICAL_
2 1
A/C_HEATER_POWER1 CANOPY_ _1
1 1 2 1 2 OUTLET)
WORKLIGHT,
4 3 2 1 C_OF02_M
2 M3 L(+) iniFuses
8 7 6 5 C_WF02_7283-7026-30_1
FUSE 2 1 GND2
3 2 1 C_OF02_7123-2820_1 _1
C_OF02_7123-2 1 (BEACON)
820_1 C_OF08_7123-
1
C_WF03_6189-0165_1 C_LEF01_M3_1 C_OF02_M
6083-30_1 DOC_OUTLET_TEMP_SENSOR,D ELECTRICAL_OUTLET 2 1 iniFuses
FUSE(STARTER M8
_1
_SYGNAL)
BEACON_SWITCH C_CBF01_ 2 1 1 C_OF02_M
CAB_WORKLIGHT,B 1 iniFuses
2 _1
FUSE(FRONT-
2 1 C_LAF01
to_MAIN(A/C_HEATER_POWER1) C_WF02_7283-7028-10_1 _7009-1
4 3 2 1 WORKLIGHT) 836_1
1 CANOPY_ C_OF02_7123-8322_1
C_OF02_M
10 9 8 7 6 5 WORKLIGHT, iniFuses
1 2 3 FUSE(BLOWER) _1
L(-) 2 1
C_OF10_7123-8307
_1
C_WM03_6188-0129_1 C_CBF01_1 1 2 1
C_OF02_M FUSE(WIPER/
iniFuses WASHER)
C_OF02_M _1
iniFuses
CAB_WORKLIGHT,B _1
C_CAM01_
FUSE 2 1
1 GND3
(FUEL_PUMP)
1 C_OF02_M
iniFuses
1
CANOPY_ FUSE(CAB- 2 1 _1
WORKLIGHT, WORKLIGHT) M8
R(+)
C_CAM01_1 C_OF02_M
iniFuses GLOW,D
1 2 1 _1 C_LAF01
_7009-1
1 836_1
C_OF02_M
iniFuses FUSE(HEATER, M4
C_CBF01_
_1 FUELFILTER)
1
C_LEF01_
2 1 M4_1 HEATER
(FUEL_FILTER)
C_OF02_M
iniFuses
_1
2 1
CONNECTOR CHART 1 (KX057-4 US, CA)
C_WF02_
6-17614
6-6_1
KiSC issued 04, 2021 A
HORN(+) JS_CONTROL(L) RADIO(AC) RELAY(ECU_ SBF-BOX SOLENOID SPEAKER(L-) SUB_WORK_LIGHT TRAVEL_ WIPER_SWITCH to_J/C(CAN,MAIN) to_MAIN
MAINPOWER) (AUX2-L) ALARM (WORKLIGHT)
M5 M5 (REAR,+)
1 1 3 2 1 4 3 2 1
1 2 1 1
4 3 2 1 3 2 1 1 6 5 4 8 7 6 5
4 3
8 7 6 5 5
C_OF06_7123-2860_ C_WF08_7283-1081-
1
C_OF01_7123-2010 1 4 2 M6 M5 C_WF02_ C_CAM01_1
_1 C_CBF01_ 174352- C_CAM01 1 10_1 2
1 C_OF06_7357-5155-30 2_1 _1 C_CBF01_
C_WF08_6195-0051_1 C_OF05_M _1 1
-ISO_1 C_OM
HORN(-) to_MAIN(SUB_WORK WORKLIGHT_SWITCH J/C(CAN,MAIN)
02_7
RADIO(GND) SENSOR,FUEL SOLENOID SPEAKER(R) _LIGHT)
TRAVEL_ 122-
(AUX2-R) 1 ALARM 1 2 3 4 2820
1 4 3 2 1 _1
RELAY(GLOW),4 (REAR,GND)
1 3 2 1 10 9 8 7 6 5
1 5 6 7 8
2 1
JS_CONTROL(R) 2 1 to_
3 C_WF03_7283-8730-30 C_OF10_7123-8307_
C_OF01_7123-2010 _1 C_CBF01_1 WORKLIGHT
C_WF02_ 1 C_WM08_7382-1481-
_1 1 2 174352- C_OF02_ 10_1
C_CAM01_
2_1 7123-28
1 4
4 3 2 1 SERVICE_TOOL
20_1 C_CAM01_ to_CAB(WIPER) 1
INJECTOR_1,D SUCTION_CONTROL_ 1
8 7 6 5 C_OF04_P
to_J/C-INJ-GND,D 2
SOLENOID VALVE,B
RADIOFRAME -ISO_1 2 1 (E/F) 2 1
1 (GND) SPEAKER(R-) 2 1 TRAVEL_
4 3 PRESSURE_ 6 5 4 3 2 1 C_OF
C_WF08_6195-0051_1 4 3 02_7
2 SENSOR
1 2 1 1 C_WF02_6189-0039 123-
RELAY(HORN) C_WF04_174257-2_1 _1 C_WF06_7283-8850- 2820
C_OF04_7283-1040_ 30_1 _1
C_WF02_6189-0611 1
_1 C_WF02_ 3 2 1
3 174352-
KEY_SWITCH 2_1
C_CAM01_ 5 J/C-INJ-GND,D
C_CAM01 C_WF03_7
1 SWITCH(DPF,INHIBIT) to_WIPER
INJECTOR_2,D _1 223-6536
1 4 2 SERVICE_TOOL(CAP)
2 1 SOLENOID
-30_1
1 2 3 4 5 6
RAIL_
1 3 C_OF05_M
(LEVER_LOCK) 1 2
PRESSURE_
-ISO_1 1 2 SPEAKER(R-) 4 3 2 1
2 SENSOR,D TRAVEL_SPEED 3 4
C_WM06_7182-9631-
C_WF03_7123-6234-40
3 4 &ANGLE_BLADE
_1 2 1 10 9 8 7 6 5 40_1
1 _SW
C_WF02_6189-0611 C_OM04_7282-1042_
_1
3 2 1 1
RELAY(LIGHT) C_WM04_174259-2_1 C_WF02_
LCD_METER 7283-20 C_OF10_7123-8307 to_J/C-SLD-GND,D
C_WF03_1 _1
2 1
90-30_1
73091-2_
INJECTOR_3,D 1 3 C_CAM01 4 3 to_CAMSHAFT_SENSOR
7 6 5 4 3 2 1 _1 6 5 4 3 2 1
5
SERVO_MOTOR SOLENOID C_WF04_6
1 14 13 12 11 10 9 8 1 4 2 C_WF06_7283-8850-
REGISTER (MULTI) 180-4181 2 1 30_1
2 (120ohm) STARTER(50),D SWITCH(LEVER_LOCK)
_1
C_OF14_7283-5832_1 7 6 5 4 3 2 1 4 3
C_OF05_M
-ISO_1 2 1
C_WF02_6189-0611
_1
2 1 C_OF07_IL-AG5-7S-S3
2 1 TRAVEL_SPEED C_WF04_7123-7444- J/C-SLD-GND,D
LCD_METER_REMOTE_ C1_1 1 _SW 40_1
WAKEUP_SW C_WF02_
C_WF02_7 RELAY(POWER) 7283-20 C_WF02_6195-0003 1 2 3 4 5 6
123-6423 C_OF01_
INJECTOR_4,D 90-30_1 _1
-30_1 SOLENOID(ANGLE-L) 7123-28 1 2 to_MAIN(CAMSHAFT_
1 2 10_1
SENSOR)
3 C_WM06_7182-9631-
1 3 SOLENOID
40_1
2 1 (TRAVEL_ SWITCH(WATER_LEVEL)
2 C_WM02_6187-2802_1 1 2 SPEED) STOP_SWITCH C_WM03_6 1 2
RELAY 092-0013
(BEACON) 4 C_WF02_7283-2090-30
_1 3 4
C_WF02_6189-0611 _1
OIL-SW,B 2 1 to_MAIN(SENSOR,CRSB)
_1
3 C_OF04_P 2 1 1 2
-ISO_1 C_WM04_7222-7444-
C_WF02_6189-0176 WASHER_TANK 40_1
1 5 SOLENOID(ANGLE-R) _1 1 2 3
INTAKE_THROTTLE_
C_WF02_ C_WM02_
MOTOR,D 1 4 2 7283-20 6187-28 4 5 6
C_OF01_172320-2_1 RELAY 2 1 90-30_1 01_1
1
THERMOSTAT to_J/C(CAN,EGR,SERVICE)
C_OF05_M (STARTER)
6 5 4 3 2 1 -ISO_1 2 C_WM06_33482-0601
C_WF02_7283-2090-30 _1
OIL-SW,D 3 _1 SUB_WORK_
SPEAKER(L) 5 4 3 2 1 6 5 4 3 2 1
C_WF06_7283-1968 5 LIGHT C_OF02_7
-30_1 RELAY 123-2820
1 1 4 2 C_OF05_7283-1050 _1 to_SENSOR(CRSB)
(BLOWER) SOLENOID(AUX1-L) 1 C_WF06_7283-8850-
1 _1 30_1
C_OF01_172320-2_1 3 C_OF05_M 2 3 2 1
-ISO_1 2 1 WATER_TEMP
5 TRAVEL_ALARM _SENSOR,D 6 5 4
C_OF02_ C_CBF01 (FRONT,+)
RADIO(+B) 1 4 2 C_WF02_174352-2_1 7123-28 _1
RESISTOR_ 20_1 J/C(CAN,EGR,SERVICE) C_WF06_33472-0606
BLOWER 1 2 1 _1
1 C_OF05_M
-ISO_1 SOLENOID(AUX1-R) to_MAIN 1 2 3 4 5 6
2 1 SPEAKER(L+) (SUB_WORK_ C_WF02_1
LIGHT) 78392-6_
4 3 2 1 C_CBF01_1 1
C_CBF01_1 1 C_WM06_7182-9630-
30_1
C_OF04_6 C_WF02_174352-2_1 1
RELAY 098-0514 TRAVEL_ALARM WIPER,F
_1 (FRONT,GND)
(COMPRESSOR)
C_CAM01
_1
2 1
ROOM_LIGHT C_CAM01 1
3 _1 4 3
5
C_OF04_6
1 4 2 3 2 1 090-1011
C_CAM01_1
_1
C_OF05_M C_OF03_6
-ISO_1 130-2330
_1
RELAY(CRS_
MAIN) SBF,MAIN1-2
3
2 1
5
1 4 2 C_OF02_7
323-3220
_1
C_OF05_M
-ISO_1
CONNECTOR CHART 2 (KX057-4 US, CA)
KiSC issued 04, 2021 A
R REVISED CONTENTS
KiSC issued 04, 2021 A
REVISED CONTENTS
CONTENTS
1. [A] Tester .......................................................................................................................................R-1
KiSC issued 04, 2021 A
KX057-4,U55-4, WSM REVISED CONTENS
1. [A] Tester
Using the tester mode to check information about the sensor statuses and switches.
Press and hold switch 5, and turn the
(1) starter key to [RUN].
(A)STOP, (B)RUN, (C)START
Select "English" and press switch 5.
(2)
Select "Diagnosis" and press switch 5.
(3)
Select "Tester" and press switch 5.
(4)
To [Screen 1]
(a)
RY9212182ELS0068US0
[Screen 1]
Item Description/std. value
When engine stopped: 0
Engine RPM
Engine RPM: 1050 rpm
Battery voltage Battery voltage ±0.5V
Before engine start: ON
Oil
After engine start: OFF
Before engine start: ON
Charge
After engine start: OFF
Ket to START position : ON
Starter
Other position : OFF
RY9212182ELS0019US0
[Screen 2]
Item Description/std. value
Water temperature voltage
Common rail spec. voltage (V) is dummy data
Water Temperature (°C)
Fuel voltage E : High, F : Low
Full tank (F) : 5Ω or lower
Fuel resistance
Empty (E) : 101.0Ω or lower
SW close to fuel filler port. ON when switch
Fuel supply SW
pressed.
RY92121683REV0001US0
Fuel dot number
Design Value KX057-4 U55-4
Full 5Ω or less
1/2 full 34.65 Ω 33.64 Ω
3 dots left * 96.92 Ω 92.5 Ω
Empty 101.0Ω or higher
* Fuel warning
RY9212166ELS0020US0
R-1 KiSC issued 04, 2021 A
EDITOR:
KUBOTA CORPORATION
CONSTRUCTION MACHINERY
SERVICE TECHNICAL SUPPORT DEPARTMENT
1-1 NAKAMIYA-OHIKE 1-CHOME, HIRAKATA-CITY, OSAKA, 573-8573, JAPAN
PHONE : (81)72-840-1195
FAX : (81)72-890-2883
E-mail : kbt_g.ce-sv@kubota.com
Printed in Japan 2021. 04, H, EI, EI, engusa Code No. RY911-21683
KUBOTA Corporation 2013. 02, H, EI, EI, engusa
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