0-1 TB53FR

TB53FR 0-2
0-3 TB53FR
 FOREWORD

This manual is intended for persons who engage in maintenance operations, and explains
procedures for disassembly and reassembly of the machine, check and maintenance procedures,
maintenance reference values, troubleshooting and outline specifications, etc. Please use this
manual as a reference in service activities to improve maintenance techniques.
Further, please be advised that items contained in this manual are subject to change without notice
due to design modifications, etc.

MACHINE FRONT AND REAR, LEFT AND RIGHT

The end where the dozer blade is mounted is the front and the end with the travel motors is the
rear. Also the right and left sides of the operator when he is seated in the driver’s seat are the right
and left sides of the machine.

MACHINE SERIAL NUMBER

The machine serial number is stamped on the identification plate. When sending reports and
inquiries, and when ordering parts, etc., be sure to include this number.

MANUAL CONTROL
Information on those to whom this manual is distributed is recorded in the ledger in the section
in charge at this company, so please decide on a person to be in charge of it and control it. When
there are updates or additions, etc., we will notify the person in charge.

TB53FR 0-4
FOOT OF THE PAGE

L4A100

1. Page number
The following page numbers are assigned to each respective page. And if there are additional pages, an addition
code is supplied. Please file the sheets in the order of the page numbers.

Page No.
X–XX
Page number within section
Section Number

Page Addition
X–XX–X
Addition Code

Example: II-8
II-9
II-9-1 ............... A page is added between page 9 and page 10.
II-10

If a page has been revised, it is to be used in place of the page used before revision and it is not necessary to keep
the old page.

2. Revision number
Indicates the revision of this manual. This number is printed on the page that reflects this revision.

3. Model (s)

SYMBOLS
means “Please refer to the section quoted.”

Indicates the tightening torque at the specific section that requires special attention in designing.

Indicates the mass of a part or device.

0-5 TB53FR
TB53FR 0-6
 I . GENERAL
II . SPECIFICATIONS
III . MACHINE CONFIGURATION
IV . HYDRAULIC UNITS
V. TROUBLESHOOTING
VI . ENGINE

0-7 TB53FR
TB53FR 0-8
I . GENERAL

I-1 TB53FR
GENERAL

CONTENTS

Safety Precautions ................................................................................................................................................. 3

Cautions during Disassembly and Assembly ........................................................................................................ 9
Cautions during Removal and Installation of the Hydraulic Units ..................................................................... 10
Cautions during Removal and Installation of Piping .......................................................................................... 11
Handling of Seals ................................................................................................................................................ 12
Tightening Torques ............................................................................................................................................. 13

TB53FR I-2
 GENERAL
SAFETY PRECAUTIONS

SAFETY ALERT SYMBOL

This symbol means Attention! Be Alert! Your Safety Is Involved.
The message that follows the symbol contains important information about safety.
Read and understand the message to avoid personal injury or death.

■ SIGNAL WORDS
Safety messages appearing in this manual and on machine decals are identified by the words “DANGER”,
“WARNING” and “CAUTION”. These signal words mean the following:

DANGER WARNING CAUTION

The word “DANGER” indicates The word “WARNING” indi- The word “CAUTION” indi-
an imminently hazardous situ- cates a potentially hazardous cates a potentially hazardous
ation which, if not avoided, can situation which, if not avoided, situation which, if not avoided,
result in serious injury or death. could result in serious injury or may result in minor or moder-
death. ate injury.

IMPORTANT: The word “IMPORTANT” is used to alert against operators and maintenance personnel
about situations which can result in possible damage to the machine and its components.

This manual is intended for trained and qualified personnel only. Warnings or cautions described in this manual do
not necessarily cover all safety measures. For maintenance work, each person must take adequate safety precautions
against possible hazards present in the respective working environment.

Observe all safety rules

• Operation, inspection and maintenance of this ma-

chine must be performed only by a trained and
qualified person.
• All rules, regulations, precautions and safety pro-
cedures must be understood and followed when
performing operation, inspection and maintenance
of this machine.
• Do not perform any operation, inspection and
maintenance of this machine when under the ad-
verse influence of alcohol, drugs, medication, fa-
tigue, or insufficient sleep.

• Wear a hard hat, safety shoes, safety glasses, filter

Wear appropriate clothing and personal mask, heavy gloves, ear protection and other pro-
protective equipment tective equipment as required by job conditions.
Wear required appropriate equipment such as safety
• Do not wear loose clothing or any accessory that glasses and filter mask when using grinders, ham-
can catch on controls or in moving parts. mers or compressed air, as metal fragments or
• Do not wear oily or fuel stained clothing that can other objects can fly and cause serious personal
catch fire. injury.
• Use hearing protection when operating the ma-
chine. Loud prolonged noise can cause hearing
impairments, even the total loss of hearing.

I-3 TB53FR
GENERAL
Provide a fire extinguisher and first aid Anti-explosive lighting
kit

Use anti-explosive electrical fixtures and lights when

• Know where a fire extinguisher and first aid kit are inspecting fuel, oil, coolant, battery fluid, etc. If
located and understand how to use them. lighting that is not anti-explosive should break, the
• Know how to contact emergency assistance and substance could ignite, resulting in serious injury or
first aid help. death.

Attach a “DO NOT OPERATE” tag Do not allow unauthorized personnel in

the work area
Severe injury could result if an unauthorized person
should start the engine or touch controls during in-
spection or maintenance.
• Stop the engine and remove the key before per-
forming maintenance.
• Attach a “DO NOT OPERATE” tag to the starter
switch or control lever.

Use the correct tools

Do not allow unauthorized personnel in the work
area. Chips or other debris can fly off machine parts
when grinding, welding or using a hammer.

Prepare the work area

• Select a firm, level work area. Make sure there is

adequate light and, if indoors, ventilation.
• Clear obstacles and dangerous objects. Eliminate
Do not use damaged or weakened tools or tools slippery areas.
designed for other purposes. Use tools suited for the
operation at hand.

Replace important safety parts

periodically

• Replace fuel hoses periodically. Fuel hoses be-

come weaker over time, even if they appear to be
in good shape.
• Replace important safety parts whenever an ir-
regularity is found, even if it is before the normal
time for replacement.

TB53FR I-4
 GENERAL
Always clean the machine Securely block the machine or any
component that may fall

• Clean the machine before performing maintenance.

• Cover electrical parts when washing the machine. • Before performing maintenance or repairs under
Water on electrical parts could cause short-circuits the machine, set all working equipment against the
or malfunctions. ground or in the lowermost position.
Do not use water or steam to wash the battery, • Securely block the tracks.
sensors, connectors or the operator’s seat area. • If you must work beneath the raised machine or
equipment, always use wood blocks, jack-stands
or other rigid and stable supports. Never get under
Stop the engine before performing the machine or working equipment if they are not
maintenance sufficiently supported. This procedure is espe-
cially important when working on hydraulic cylin-
• Avoid lubrication or mechanical adjustments with ders.
the machine in motion or with the engine running
while stationary.
• If maintenance must be performed with the engine
running, always work as a 2-person team with one
person sitting in the operator’s seat while the other Securely block the working equipment
works on the machine.
• When performing maintenance, be sure to keep To prevent unexpected movement, securely block the
your body and clothing away from moving working equipment when repairing or replacing the
parts. cutting edges or bucket teeth.

Stay clear of moving parts

Secure the engine hood or cover when

opened

Be sure to secure the engine hood or cover when

opening it. Do not open the engine hood or cover on
slopes or in strong wind.

• Stay clear of all rotating and moving parts. Wrap-

ping or entanglement may result in serious injury Cautions on tilting up the platform
or death.
• Keep hands, clothing and tools away from the • Raising or lowering the platform while the engine
rotating fan and running fan belts. is running may cause the machine to move, and
cause serious injury or death.
Stop the engine before raising or lowering the
platform.
• When the floor is tilted up, support it firmly with
the stopper to prevent it from falling.

I-5 TB53FR
GENERAL
Place heavy objects in a stable position Handling of hoses

Fuel, oil or hydraulic fluid leaks can cause a fire.

• Do not twist, bend or hit the hoses.
• Never use twisted, bent or cracked hoses, tubes and
pipes. They may burst.
• Retighten loose connections.

Be careful with hot and pressurized

components
When removing or installing the hoe attachment,
place it in a stable position so that it does not tip over.

Use caution when fueling

Stop the engine and allow the machine to cool down

before performing inspection and maintenance.
• The engine, muffler, radiator, hydraulic lines, slid-
ing parts and many other parts of the machine are
hot directly after the engine is stopped. Touching
these parts will cause burns.
• The engine coolant, oil and hydraulic fluid are also
hot and under high pressure.
Be careful when loosening caps and plugs. Work-
• Do not smoke or permit open flames while fueling ing on the machine under these conditions could
or near fueling operations. result in burns or injuries due to the hot oil spurting
• Never remove the fuel cap or refuel with the engine out.
running or hot. Never allow fuel to spill on hot
machine components.
• Maintain control of the fuel filler nozzle when Be careful with hot cooling systems
filling the tank.
• Do not fill the fuel tank to capacity. Allow room for
expansion.
• Clean up spilled fuel immediately.
• Tighten the fuel tank cap securely. Should the fuel
cap be lost, replace it only with the original
manufacturer’s approved cap. Use of a non-ap-
proved cap without proper venting may result in
pressurization of the tank.
• Never use fuel for cleaning purposes.
• Use the correct fuel grade for the operating season. Do not remove the radiator cap or drain plugs when
the coolant is hot. Stop the engine, let the engine and
radiator cool and loosen the radiator cap or drain plugs
slowly.

TB53FR I-6
 GENERAL
Be careful with fluids under pressure Be careful with grease under pressure

The track adjuster contains highly pressurized grease.

If the tension is adjusted without following the pre-
Pressure can be maintained in the hydraulic circuit scribed procedure, the grease discharge valve may fly
long after the engine has been shut down. off, resulting in injury.
• Release all pressure before working on the hydrau- • Loosen the grease discharge valve slowly. Do not
lic system. unfasten it more than one full turn.
• Hydraulic fluid under pressure can penetrate the • Do not put your face, arms, legs or body in front of
skin or eyes and cause injury, blindness or death. the grease discharge valve.
Fluid escaping from a small hole can be almost
invisible. Wear a safety goggles and heavy gloves
and use a piece of cardboard or wood to search for Disconnect the battery
suspected leaks.
If fluid is injected into the skin, it must be removed
within a few hours by a doctor familiar with this
type of injury.

Release all pressure before working on

the hydraulic system

Oil may spurt out if caps or filters are removed or

pipes disconnected before releasing the pressure in Disconnect the battery before working on the electri-
the hydraulic system. cal system or doing any welding. Remove the nega-
• Gradually loosen the vent plug to relieve tank tive (–) battery cable first. When reconnecting the
pressure. battery, connect the negative (–) battery cable last.
• Move all the control levers and pedals several
times in all directions to release the pressure from
the working equipment circuitry. (For link type
controls)
• When removing plugs or screws or disconnecting
hoses, stand to the side and loosen slowly to gradu-
ally release the internal pressure before removing.

I-7 TB53FR
GENERAL
Avoid battery hazards Checks after maintenance

• Batteries contain sulfuric acid which will damage • Gradually raise the engine speed from a low idle to
eyes or skin on contact. maximum speed and check that no oil or air is
• If acid contacts eyes, flush immediately with leaking from serviced parts.
clean water and get prompt medical attention. • Move the controls and check that the machine is
• If acid is accidentally swallowed, drink large operating properly.
quantities of water or milk and call a physician
immediately.
• If acid contacts skin or clothing, wash off imme-
diately with clean water.
• Wear safety glasses and gloves when working with Disposing of wastes
batteries.
• Batteries generate flammable and explosive gases.
Keep arcs, sparks, flames and lighted tobacco
away.
• Use a flashlight to check battery electrolyte level.
• Stop the engine and shut off electrical equipment
while inspecting or handling the battery.
• Do not short circuit the battery posts with metal
items.
• Always unfasten the negative (–) battery cable first
when disconnecting the battery cable. Always con- • Funnel spent fluids from the machine into contain-
nect the negative (–) battery cable last when fasten- ers. Disposing of fluids improperly destroys the
ing the battery cable. environment.
• Loose battery terminals may result in sparks. Be • Follow the prescribed regulations when disposing
sure to fasten terminals tightly. of oil, fuel, engine coolant, refrigerant, solvents,
• Make sure the vent caps are tightened securely. filters, batteries or other harmful substances.
• Do not charge a battery or jump-start the engine if
the battery is frozen. Warm to 15°C (60°F) or the
battery may explode.

Have a Takeuchi service agent repair

welding cracks or other damage

Ask a Takeuchi service agent to repair any welding

problems which are detected. If not feasible, make
sure the welding is done by a qualified person in a
properly equipped workplace.

Safety signs

• Keep all safety signs clean and legible.

• Replace all missing, illegible or damaged safety
and warning signs.

TB53FR I-8
 GENERAL
CAUTIONS DURING DISASSEMBLY AND
ASSEMBLY

1. Clean the machine before disassembly operation.

2. Before disassembly, check the machine condi-

tions and record them.
• Model, Machine Serial Number, Hourmeter
• Reason for Repairs, Repair History
• Dirtiness of Filters
• Fuel and Oil Conditions
• Damage to each parts, etc.

3. To make reassembly operations easy, make match-

ing marks at the necessary points.

4. Clean all disassembled parts and new parts, then

arrange them in the proper sequence.

5. Be sure to replace all seals and cotter pins, etc.,

with new parts.

6. Keep parts which should not come in contact with

oil and water separate from parts with oil on them.
• Electrical Parts, Rubber, V-Belts, etc.

7. When installing bearings, bushings and oil seals,

as a rule, use a press. When a hammer, etc., is
used, it leaves bruises.

8. Wipe all joining surfaces clean so that there is no

dirt or dust adhering to them.

9. Wrap seal tape from the front end, Wrapping it SEALING TAPE
tight and leaving 1 or 2 threads bare, Overlap the
tape by about 10 mm.

LEAVE 1 OR 2 THREAD MARGIN

10. When fitting the snap rings, the bigger, rounder

side of their circumferences should face the mat-
ing surfaces.

I-9 TB53FR
GENERAL
CAUTIONS DURING REMOVAL AND
INSTALLATION OF THE HYDRAULIC UNITS

1. Make sure that the hydraulic oil’s temperature

has dropped.

2. To prevent a loss of flow of the hydraulic oil, the

residual pressure in the piping and the internal
pressure in the hydraulic oil tank should be bled
out.

3. Be sure to install caps or plugs on all openings in PLUG

the hydraulic unit to prevent dirt from getting into

the unit through the openings.

PLUG

4. It is easy to mistake hydraulic oil adhering to the

hydraulic unit for an oil leak, so wipe the unit off
thoroughly.

5. Be sure that no damage is done to the plating on

the rod in the hydraulic cylinder.

6. As a rule, removal and installation of the hydrau-

lic cylinder should be done with the rod fully
retracted.

7. Be sure to bleed the air after replacing the hydrau-

lic oil or removing any of the hydraulic devices.
“III. Machine Configuration, Hydraulic Sys-
tem”

8. After installation of the hydraulic unit, be sure to

pressurize the hydraulic oil tank. If this operation
is forgotten, it could cause cavitation of the hy-
draulic pump. Also, it could have a drastic effect
on the life of the hydraulic pump.
“III. Machine Configuration, Hydraulic Sys-
tem”

TB53FR I-10
 GENERAL
CAUTIONS DURING REMOVAL AND
INSTALLATION OF PIPING

1. When hydraulic hoses are installed, tighten them

once to the prescribed torque, then loosen them
slightly and retighten them to the prescribed
torque.
• Tighten the fittings after the installation sur-
faces fit snugly together.
• Pieces wrapped with seal tape are excluded.

2. Use 2 spanners, each on an opposite side, to

remove and tighten fittings so that the hoses or
steel pipes are not twisted.

3. After installation of hydraulic hoses or steel pipes,

apply the maximum working pressure 5 or 6 times
and confirm that there is no leakage.

I-11 TB53FR
GENERAL
HANDLING OF SEALS

1. Clean the grooves for O-rings and if there is any RIDGE

ridge, etc., remove it.

DIRT

2. Be careful not to twist O-rings. If an O-ring is

twisted, remove the twist with the fingertips.

3. During insertion, be careful not to damage the

seal.

4. Handling of Floating Seals

• Wipe all oil off the O-ring and housing of the
floating seal.
• When assembling, apply a thin coating of gear
oil to the contact surface of the housing.
• After assembly, turn the seal 2 or 3 times to get
it to fit snugly.

5. Apply grease to the lip of the oil seal.

• This is to prevent wear when it is first started up
after assembly.

GREASE

TB53FR I-12
 GENERAL
TIGHTENING TORQUES

Hydraulic Hoses
UNION NUT
Torque
Hose Fitting Size Union Nut (G) Taper Thread (R)
N·m ft-lb N·m ft-lb
+4.9 +3.5 TAPER THREAD
1/8 9.8 0 7.3 0 11.8 ±1.2 8.7 ±0.8
1/4 24.5 +4.9
0 18.1 +3.5
0 29.4 ±2.9 21.7 ±2.1
+4.9 +3.5
3/8 49 0 36.2 0 53.9 ±5.4 39.8 ±3.9
1/2 58.8 +4.9
0 43.4 +3.5
0 88.3 ±8.8 65.1 ±6.4
+4.9 +3.5
3/4 117.7 0 86.8 0 147.1 ±14.7 108.5 ±10.7
+4.9 +3.5
1 137.3 0 101.3 0 196.1 ±19.6 144.7 ±14.3

Bite Type Pipe Fitting for Steel Pipe

Pipe Outer Diameter Torque

(mm) N·m ft-lb
8 34.3 ±4.9 25.3 ±3.5
10 41.7 ±2.5 30.7 ±1.7
12 58.8 ±4.9 43.4 ±3.5
15 88.3 ±4.9 65.1 ±3.5
16 93.2 ±4.9 68.7 ±3.5
18 132.4 ±4.9 97.6 ±3.5
22 205.9 ±9.8 151.8 ±7.2
27.2 245.2 ±9.8 181.0 ±7.2
28 313.8 ±19.6 231.4 ±14.3
32 313.8 ±19.6 231.4 ±14.3
35 411.9 ±19.6 303.7 ±14.3

I-13 TB53FR
GENERAL
Joints for Piping
Torque
Nominal Thread
Diameter Steel Cast Steel
(R) N·m ft-lb N·m ft-lb
1/8 11.8 ±1.2 8.7 ±0.8 10.8 ±1.1 8.0 ±0.7
1/4 29.4 ±2.9 21.7 ±2.1 24.5 ±2.5 18.1 ±1.7
3/8 53.9 ±5.4 39.8 ±3.9 49 ±4.9 36.2 ±3.5
1/2 88.3 ±8.8 65.1 ±6.4 73.5 ±7.4 54.3 ±5.3
3/4 147.1 ±14.7 108.5 ±10.7 127.5 ±12.7 94.1 ±9.3
1 196.1 ±19.2 144.7 ±14.3 171.6 ±17.2 126.6 ±12.5

Joints for Piping (O-ring Seal Type)

O-RING
Nominal Thread Torque
Diameter
(G) N·m ft-lb
1/8 19.6 ±2.0 14.5 ±1.4
1/4 34.3 ±4.9 25.3 ±3.5
3/8 53.9 ±4.9 39.8 ±3.5
1/2 63.7 ±4.9 47.0 ±3.5
3/4 93.2 ±4.9 68.7 ±3.5
1 107.9 ±9.8 79.5 ±7.2
1-1/4 117.7 ±9.8 86.8 ±7.2
1-1/2 137.3 ±9.8 101.2 ±7.2

Nominal Thread Torque

Diameter
(UNF) N·m ft-lb
7/16–20 16.7 ±2.0 12.3 ±1.4
1/2–20 22.6 ±2.0 16.6 ±1.4
9/16–18 31.4 ±2.9 23.1 ±2.1
3/4–16 59.8 ±4.9 44.1 ±3.5
1-1/16–12 102.0 ±5.9 75.2 ±4.4
1-5/16–12 135.3 ±7.8 99.8 ±5.8
1-5/8–12 181.4 ±9.8 133.8 ±7.2

TB53FR I-14
 GENERAL
Bolts and Nuts (for ISO Strength Category 10.9)
Torque
Thread Size × Pitch General Tightening Points Special Tightening Points
N·m kgf·m ft-lb N·m kgf·m ft-lb
M6 × 1.0 9.8 ±0.5 1.0 ±0.05 7.2 ±0.4 11.8 ±0.6 1.2 ±0.06 8.7 ±0.4
M 8 × 1.25 22.6 ±1.1 2.3 ±0.11 16.6 ±0.8 26.5 ±1.3 2.7 ±0.13 19.5 ±0.9
M10 × 1.5 47.1 ±2.4 4.8 ±0.24 34.7 ±1.7 54.9 ±2.7 5.6 ±0.28 40.5 ±2.0
Coarse M12 × 1.75 83.4 ±4.1 8.5 ±0.42 61.5 ±3.0 97.1 ±4.8 9.9 ±0.49 71.6 ±3.5
M14 × 2.0 134.4 ±6.7 13.7 ±0.68 99.1 ±4.9 155.9 ±7.7 15.9 ±0.79 115.0 ±5.7
M16 × 2.0 207.9 ±10.4 21.2 ±1.06 153.3 ±7.7 241.2 ±12.1 24.6 ±1.23 177.9 ±8.9
M20 × 2.5 410.9 ±20.5 41.9 ±2.09 303.1 ±15.1 475.6 ±23.7 48.5 ±2.42 350.8 ±17.5
M8 × 1.0 24.5 ±1.2 2.5 ±0.12 18.1 ±0.9 28.4 ±1.4 2.9 ±0.14 21.0 ±1.0
M10 × 1.25 50.0 ±2.5 5.1 ±0.25 36.9 ±1.8 58.8 ±2.9 6.0 ±0.30 43.4 ±2.2
M12 × 1.5 87.3 ±4.3 8.9 ±0.44 64.4 ±3.2 102.0 ±5.1 10.4 ±0.52 75.2 ±3.8
Fine
M14 × 1.5 135.3 ±6.8 13.8 ±0.69 99.9 ±5.0 157.9 ±7.8 16.1 ±0.80 116.5 ±5.8
M16 × 1.5 220.6 ±11.0 22.5 ±1.12 162.7 ±8.1 256.0 ±12.7 26.1 ±1.30 188.8 ±9.4
M20 × 1.5 452.1 ±22.6 46.1 ±2.30 333.4 ±16.6 524.7 ±26.1 53.5 ±2.66 387.0 ±19.2

1. General Tightening Points (Non-lubricated)

• All securing points other than the special tight-
ening points.

2. Special Tightening Points (Grease with molyb-

denum disulfide applied.)
• Points where particularly necessary due to
function.
Special tightening positions and associated
instructions are given in the text.

3. Points where thread-locking compound is used

(Three Bond #1324 is applied.)
Thread-locking compound positions and associ-
ated instructions are given in the text.

4. If tightening torque values are provided in this

manual, then tightening should be done accord-
ing to those values.
(This indicates that the tightening torque differs
from the values given in this table.)

5. In order to tighten bolts and nuts evenly, they

should be tightened alternately top, bottom, left,
right.

I-15 TB53FR
GENERAL

TB53FR I-16
II . SPECIFICATIONS

I-17
II-1 TB53FR
SPECIFICATIONS

CONTENTS

Names of Components .......................................................................................................................................... 3

Dimensions ............................................................................................................................................................ 4
Lifting Capacities .................................................................................................................................................. 5
Specification Tables .............................................................................................................................................. 7
Mass Tables ......................................................................................................................................................... 12
Recommended Lubricants ................................................................................................................................... 13
Servicing Standards ............................................................................................................................................. 14
Standards for Judging Performance ..................................................................................................................... 17
Reference Value Table .................................................................................................................................. 17
Methods for Inspecting Performance ............................................................................................................ 19

In regard to Standard Values and Allowable Values

The terms used in the items “Servicing Standards” and “ Standards for Judging Performance” have the following
meanings.

Standard Value ......... This indicates the standard value for the new machine at the time of shipping from the factory.
It should be used as the target value for maintenance work after operation.
Allowable Value ....... The dimensions of parts change during use because of wear and deformation. Also, the
performance of pumps, motors, and other hydraulic equipment drops, and this is the
estimated value indicating the use limit for the respective part. It is decided under reference
to the standard at the time of shipping, the results of various tests, etc. As the use conditions,
the degree of repairs, etc., differ for each machine, these should be combined and used as
reference for servicing standards and standards for judging performance.
* Do not use the standard values and the allowable values as standards for customer claims.

TB53FR I-18
II-2
NAMES OF COMPONENTS SPECIFICATIONS
NAMES OF COMPONENTS

9 1
7
4
19 11
25
24

23

3
26

12

22

16

27 6

21 17 15
18
10
29 14
30
13
28

20 J1B000

1. Cab 11. Engine 21. Bucket

2. Engine hood 12. Crawler belt 22. Bucket cylinder
3. Fuel tank 13. Idler 23. Arm
4. Hydraulic tank 14. Track roller 24. Arm cylinder
5. Hydraulic pump 15. Carrier roller 25. Boom
6. Slew motor 16. Travel motor 26. Boom cylinder
7. Pilot valve 17. Right link arm 27. Boom bracket
8. Battery 18. Track adjuster 28. Offset cylinder
9. Control valve 19. Solenoid valve 29. Dozer blade
10. Left link arm 20. Swivel joint 30. Dozer blade cylinder

II-3 TB53FR
SPECIFICATIONS DIMENSIONS

DIMENSIONS
Machine Dimensions
Unit: mm
T
L Canopy Cab
N A 5330 ←
P B 1860 ←
M
C 2580 2565
D
D 1000 ←
U
E 615 ←
F 1985 ←
B
G 2500 ←
H 2000 ←
J 400 ←
C
K 300 ←
S E L 1285 ←
K F M 720 ←
J G
H R N 825 ←
Q P 2000 ←
A
Q 4085 ←
J1K001A

R 1520 ←
S 430 ←
T 30° ←
U 15° ←

Operating Range
Unit: mm
Canopy Cab
A 5905 ←
E B 5765 ←
F C 3590 ←
D 2780 ←
G E 5535 ←
J

F 3880 ←
K G 1515 ←
D H 3885 ←
C
J 335 ←
K 320 ←

J1K002A

TB53FR II-4
LIFTING CAPACITIES SPECIFICATIONS
LIFTING CAPACITIES
• The loads in the charts do not exceed 87% of
hydraulic lift capacity or 75% of tipping load.
• Rated lift capacities limited by rated hydraulic lift
capacity are identified by an asterisk. (*)
• The mass of slings and any auxiliary lifting devices
shall be deducted from the rated load to determine
the net load that may be lifted.
• The load point is the bucket hinge pin, and the
bucket posture is with the standard bucket com-
pletely retracted under the arm.
• Units: kg (lbs.)

Load hooking system

A load hooking system with all of the following
capacities must be provided and used.
1. A system which can withstand a weight of two
times the rated lift capacity no matter at what
position the load is applied.
2. A system in which there is no risk of the lifted load
falling from the hooking device, for example one
equipped with a hook slippage prevention device.
3. A system in which there is no risk of the hooking
system slipping from the hoe attachment.

WARNING
• DO NOT attempt to lift or hold any load that is
greater than these rated values at their speci-
fied load radii and height.
• All rated lift capacities are based on the ma-
chine being level and on a firm supporting
surface. For safe working loads, the user is
expected to make due allowance for the par-
ticular job conditions such as soft or uneven
ground, non-level condition, side loads, haz-
ardous conditions, experience of personnel,
etc. The operator and other personnel should
fully acquaint themselves with the operator’s
manual furnished by the manufacturer before
operating this machine, and rules for safe
operation of equipment shall be adhered to at
all times.

II-5 TB53FR
SPECIFICATIONS LIFTING CAPACITIES

Equipped with Standard Arm Unit: kg (lbs.)

Over Front; Dozer Blade Down Over Front; Dozer Blade Up

J1K003A

Over Rear Over Side

J1K004A

TB53FR II-6
SPECIFICATION TABLES SPECIFICATIONS
SPECIFICATION TABLES
SPECIFICATIONS

Serial Number 15810005~

Machine Type Canopy Cab
Machine Mass (not including operator)
Rubber Crawler kg 5115 5195
Steel Crawler kg 5195 5275
Engine Rated Output kW/min–1 27.9/2300 ←
Bucket Capacity (Standard Bucket)
Rated Capacity m3 0.141 ←
Struck Capacity m3 0.102 ←
Performance
Slew Speed min–1 10 ←
Travel Speed: 1st/2nd km/h 3.0/5.2 ←
Gradeability % (degree) 58 (30) ←
Ground Pressure: Rubber Crawler kPa 29.4 29.8
Steel Crawler kPa 29.8 30.3
Noise Level: Sound-power dB (A)  LWA98
Sound-pressure level dB (A)  LPA79
Auxiliary Hydraulic Flow Rate L/min 55.9 ←
Dimensions
Overall Length in Transport Position mm 5330 ←
Overall Width mm 2000 ←
Overall Height mm 2580 2565
Dimensions of Base Machine
Tail Swing Radius mm 1000 ←
Distance of Rearmost Upper Structure from Axis of Rotation mm 1000 ←
Clearance Height under Upper Structure mm 615 ←
Crawler Base mm 1985 ←
Crawler: Overall Length mm 2500 ←
Overall Width mm 2000 ←
Crawler Shoe Width mm 400 ←
Minimum Ground Clearance mm 300 ←

II-7 TB53FR
SPECIFICATIONS SPECIFICATION TABLES

Serial Number 15810005~

Machine Type Canopy Cab
Working Equipment (Hoe Attachment)
Boom Swing Angle: L.H. degree 30 ←
R.H. degree 15 ←
Maximum Reach mm 5905 ←
Maximum Reach at GRP mm 5765 ←
Minimum Level Cut Radius with Bucket Flat on GRP mm 1865 ←
Maximum Digging Depth mm 3590 ←
Radius at Maximum Digging Depth mm 2255 ←
Vertical Digging Depth mm 2780 ←
Maximum Digging Height mm 5535 ←
Radius at Maximum Digging Height mm 3210 ←
Maximum Dumping Height mm 3880 ←
Radius at Maximum Dumping Height mm 3060 ←
Minimum Dumping Height mm 1515 ←
Minimum Front Swing Radius mm 2350 ←
Minimum Front Swing Radius at Boom Offset mm 1285 ←
Overall Height at Minimum Front Swing Radius mm 4215 ←
Overall Height at Minimum Front Swing Radius at Boom Offset mm 4400 ←
Maximum Bucket Offset Volume: Left mm 720 ←
Right mm 825 ←
Digging Force: Bucket kN 36.3 ←
Arm kN 25.2 ←
Working Equipment (Dozer Blade)
Dozer Blade: Width mm 2000 ←
Height mm 430 ←
Dozer Blade: Lift Height mm 335 ←
Depth of Cut mm 320 ←

TB53FR II-8
SPECIFICATION TABLES SPECIFICATIONS
SPECIFICATIONS OF DEVICE

Serial Number 15810005~

Engine
Model Yanmar 4TNE88-ETBZ
Type 4-Cycle, vertical, water-cooled, in-line, 4-cylinder diesel engine
Number of Cylinders-Bore × Stroke mm 4-88 × 90
Total Displacement mL 2189
Compression Ratio 18.0
Performance
Maximum Torque N·m/min-1 133~145/1400
Maximum No-load R.P.M. min-1 2450 ±25
Minimum No-load R.P.M. min-1 1000 ±25
Specific Fuel Consumption g/kW·h 245
Starter V–kW 12–2.5
Generator V–kW 12–0.48
Battery V–A·h 12–55

Hydraulic Pump
Model AP2D25LV1RS7
Type Variable displacement type double axial piston plus
double gear
Delivery: P1 L/min 55.9
P2 L/min 55.9
P3 L/min 37.3
P4 L/min 10.4
Rated Pressure: P1 MPa 20.6
P2 MPa 20.6
P3 MPa 19.6
P4 MPa 3.4
Pilot Relief Valve Pressure Setting: MPa 3.4

Control Valve
Model KVSE-70-10
Number of Circuits 10
Main Relief Valve Pressure Setting: P1 MPa 20.6
P2 MPa 20.6
P3 MPa 19.6
Port Relief Valve Pressure Setting: MPa 23.5
MPa 25.5

Solenoid Valve
Model 07706-00000
Rated Pressure MPa 3.9
Rated Flow Rate: Flow through Spool mL/min 7
Pressure Reducing Valve Pressure Setting MPa 1.18

II-9 TB53FR
SPECIFICATIONS SPECIFICATION TABLES

Serial Number 15810005~

Pilot Valve
Model 07509-0000B
Secondary Side Pressure (Ports 1, 3) MPa 0.54~1.9
(Ports 2, 4) MPa 0.54~1.9
Operating Angle: Ports 1, 3 degrees 19
Ports 2, 4 degrees 25

Pilot Valve (Offset)

Model 07435-0000
Secondary Side Pressure MPa 0.5~1.96
Primary Pressure MPa 3.43

Boom Cylinder
Bore Diameter × Rod Diameter mm 110 × 60
Stroke mm 685
Fully Retracted Length (Pitch) mm 1095
Cushion Mechanism Rod Side

Arm Cylinder
Bore Diameter × Rod Diameter mm 90 × 50
Stroke mm 750
Fully Retracted Length (Pitch) mm 1146
Cushion Mechanism Both Side

Bucket Cylinder
Bore Diameter × Rod Diameter mm 80 × 45
Stroke mm 585
Fully Retracted Length (Pitch) mm 915
Cushion Mechanism 

Offset Cylinder
Bore Diameter × Rod Diameter mm 100 × 55
Stroke mm 420
Fully Retracted Length (Pitch) mm 750/783*
Cushion Mechanism 

Dozer Blade Cylinder

Bore Diameter × Rod Diameter: Standard mm 110 × 60
Stroke mm 175
Fully Retracted Length (Pitch) mm 540
Cushion Mechanism 
* Serial No. 15810019~

TB53FR II-10
SPECIFICATION TABLES SPECIFICATIONS

Serial Number 15810005~

Travel Motor
Model PHV-500
Type 2-Speed Piston Motor
Total Displacement: 1st cm3/rev 1627
2nd cm3/rev 907
Motor Displacement: 1st cm3/rev 34.2
2nd cm3/rev 19.1
Reduction Gear Ratio 47.53
2-Speed Control Pressure MPa 1.5
Parking Brake Torque N·m 3261 or more
Parking Brake Release Pressure MPa 2.0
Amount of Reduction Gear Lubricant L 0.8

Slew Motor
Model MSG-33P-19-5
Type Piston
Total Displacement cm3/rev 559
Motor Displacement cm3/rev 29.4
Reduction Gear Ratio 18.9
Relief Valve Pressure Setting MPa 18.6
Parking Brake Torque N·m 1863 or more
Parking Brake Release Pressure MPa 2.0 or more

Swivel Joint
Model YV-7095A

II-11 TB53FR
SPECIFICATIONS MASS TABLES

MASS TABLES
UNIT MASS (Dry Mass)

Unit: kg
Serial Number 15810005~

Upper Machinery
Engine 170
Radiator 11.4
Hydraulic Pump 36
Hydraulic Tank 56.4
Fuel Tank 32.3
Control Valve 42
Solenoid Valve 10
Slew Motor 56
Canopy/Cab 104/185
Counterweight 620
Boom Bracket 117
Offset Cylinder 34/38*
Left link arm 132
Right link arm 110

Lower Machinery
Swivel Joint 22
Slew Bearing 84
Crawler Belt: Rubber/Steel 219/245
Travel Motor 57
Carrier Roller 4
Track Roller: Rubber/Steel 11.6/12.1
Idler 42.3
Sprocket 15.4
Track Adjuster 23.9
Dozer Blade 197
Dozer Blade Cylinder 44

Hoe Attachment
Boom 227
Arm 95
Bucket: Standard 97
Boom Cylinder 65
Arm Cylinder 44
Bucket Cylinder 34
* Serial No. 15810019~

TB53FR II-12
RECOMMENDED LUBRICANTS SPECIFICATIONS
RECOMMENDED LUBRICANTS
Use different fuels, lubricants and greases according to the temperature, referring to the chart below.
• Change the lubricant earlier than as shown in the table if it is extremely dirty or its performance has deteriorated severely.
• Whenever possible, use the same brand of lubricant as before. If changing with a different brand, replace the entire quantity
– do not mix different brands.

Type by temperature
Replacement
Part Type -22 -4 14 32 50 68 86 104°F Capacity
interval
-30 -20 -10 0 10 20 30 40°C

SAE 5W-20
Diesel engine oil
After first 50 hrs. Upper limit: 8.6 L
Engine oil pan API service SAE 10W-30
Every 250 hrs. Lower limit: 4.2 L
CD
SAE 15W-40

Antiwear ISO VG68

hydraulic oil Total system: 120 L
Hydraulic tank ISO VG46 Every 2000 hrs.
(Option: Biode- Tank level: 79 L
gradable oil) ISO VG32

Use a clean, Quality fuel for performance and optimum engine life.
• To prevent fuel flow problems in cold weather, use diesel fuel with
Fuel tank Diesel fuel a pour point of at least -12°C (10°F) below the lowest expected
75 L
ambient temperature.
• Minimum cetane number is 45. Low temperature or high altitude
operation may require the use of fuel with a higher cetane number.

Engine cooling Coolant 30% coolant mixture

Every 1000 hours 7.2 L
system (water**+Coolant***) 50% coolant mixture

Travel reduction Gear oil SAE 90 After first 250 hrs.* 0.8 L
gear API-GL-4 Every 1000 hrs.

Carrier Roller Gear oil SAE 90  60 mL

API-GL-4

Track Roller Mobil gear   90 mL

SHG 680

Idler Gear oil SAE 90  70 mL

API-GL-4

Slew Grease Bath   2.8 L

Slew bearing  Every 50 hrs.

Lithium based
grease EP-2
Working NLGI No. 2 Daily or every 10
 As required
equipment hrs.

Levers  When required

* If the percentage of the traveling time within the total operating time is high, replace the gear oil earlier than the specified time.
** For water, use tap water (soft). Do not use well or river water.
*** When the ambient temperature drops below 0°C, add coolant (antifreeze). Follow the coolant manufacture’s instructions to
determine the mixture ratio.

II-13 TB53FR
SPECIFICATIONS SERVICING STANDARDS

SERVICING STANDARDS
TRAVEL SYSTEM

Carrier Roller
Unit: mm
Code Designated Standard ) *
Basic Dimension Allowable Value
A
84 78

B 30 
."*

Track Roller
Unit: mm
Code Designated Standard

Basic Dimension Allowable Value

A
110 106 A B

B 35 

F4B002

Drive Sprocket *
Unit: mm
Code Designated Standard

Basic Dimension Allowable Value

A
380.4 372 )
B 32 28

."*!

Idler
Unit: mm
Code Designated Standard

Basic Dimension Allowable Value

A
350 344 ) *

B 45 

."*"

TB53FR II-14
SERVICING STANDARDS SPECIFICATIONS
ATTACHMENTS

Pin and Bushing Clearances

U
M

V N
G

F
W

A
J

D
B

L
K
I

R
P
S
O

Q
L2B010

II-15 TB53FR
SPECIFICATIONS SERVICING STANDARDS

Unit: mm
Servicing
Code Connection Between Designated Standard Procedure
Basic Allowable Tolerance Standard Allowable
Dimensions Shaft Hole Clearance Clearance
A Bucket & Arm 45 -0.02 +0.17 0.14~0.22 1.0
-0.05 +0.12
B Bucket & Bucket Link 45 -0.02 +0.17 0.14~0.22 1.0
-0.05 +0.12
C Arm & Guide Link 45 -0.02 +0.17 0.14~0.22 1.0
-0.05 +0.12
Link Side
+0.17 0.14~0.22
-0.02 +0.12
D Bucket Cylinder & Bucket Link 45 1.0
-0.05 Cylinder Side
+0.1 0.02~0.15
0
E Bucket Cylinder & Arm 45 -0.02 +0.1 0.02~0.15 1.0
-0.05 0
F Arm & Boom 50 -0.02 +0.17 0.14~0.22 1.0
-0.05 +0.12
G Arm Cylinder & Arm 50 -0.02 +0.25 0.07~0.30 1.0
-0.05 +0.05
H Arm Cylinder & Boom 50 -0.02 +0.25 0.07~0.30 1.0
-0.05 +0.05
I Boom & Boom Link 60 -0.02 +0.23 0.2~0.28 1.0
-0.05 +0.18
J Boom Cylinder & Boom 60 -0.02 +0.25 0.07~0.30 1.0
-0.05 +0.05
Replace
K Boom Cylinder & Boom Link 60 -0.02 +0.25 0.07~0.30 1.0
-0.05 +0.05
L Boom Bracket & Boom 60 -0.02 +0.23 0.2~0.28 1.0
-0.05 +0.18
M Offset Cylinder & Boom Bracket 55 -0.02 +0.25 0.07~0.30 1.0
-0.05 +0.05
N Offset Cylinder & Left Link Arm 55 -0.02 +0.25 0.07~0.30 1.0
-0.05 +0.05
O Dozer Blade Cylinder & Dozer Blade 55 -0.02 +0.25 0.07~0.30 1.0
-0.05 +0.05
P Dozer Blade Cylinder & Lower Frame 55 -0.02 +0.25 0.07~0.30 1.0
-0.05 +0.05
-0.02 +0.17 0.14~0.22
Q Dozer Blade & Lower Frame 45 +0.12 1.0
-0.05
-0.02 +0.23 0.2~0.28
R Boom Link & Link 60 +0.18 1.0
-0.05
-0.02 +0.23 0.2~0.28
S Link & Boom Bracket 60 +0.18 1.0
-0.05
-0.02 +0.23 0.2~0.28
T Right Link Arm & Boom Bracket 60 +0.18 1.0
-0.05
-0.02 +0.23 0.2~0.28
U Right Link Arm & Turntable 60 +0.18 1.0
-0.05
-0.02 +0.23 0.2~0.28
V Left Link Arm & Boom Bracket 60 +0.18 1.0
-0.05
-0.02 +0.23
W Left Link Arm & Turntable 60 +0.18 0.2~0.28 1.0
-0.05

TB53FR II-16
STANDARDS FOR JUDGING PERFORMANCE SPECIFICATIONS
STANDARDS FOR JUDGING PERFORMANCE
REFERENCE VALUE TABLE

Serial Number 15810005~

Item Unit Standard Values Allowable Values
Engine Speed High min-1 2440 ±50 
Low min-1 1000 ±50 
Hydraulic Oil Pressure
Boom MPa 20.6 +1.2
-0.2 
Arm MPa 20.6 +1.2
-0.2 
Dozer Blade MPa 19.6 +1.2
-0.2 
Slew MPa 18.6 +2.0
0 
Pilot Pressure MPa 3.4 ±0.3 
Travel
Travel Speed (5 rev.)
Steel Crawler Low Speed s 34.0 ±2.0 39.4
High Speed s 20.0 ±2.0 24.8
Rubber Crawler Low Speed s 33.0 ±1.5 37.8
High Speed s 18.8 ±1.0 22.4
Travel Speed (10m)
Steel Crawler Low Speed s 13.0 ±2.0 16.3
High Speed s 7.0 ±2.0 10.0
Rubber Crawler Low Speed s 12.2 ±1.0 14.4
High Speed s 7.0 ±1.0 9.0
Travel Curve mm 125 500
Natural Travel drop mm 0 
Slew
Slew Time Normal Speed s 12.2 ±1.0 14.4
Slow Speed s  
Overrun When Slewing Stops mm 200 ±60 346
Natural Slew Drop mm 0 
Cylinders
Cylinder Speed
Boom Extended s 4.2 ±0.6 5.2
Retracted s 4.1 ±0.6 5.1
Arm Extended s 3.3 ±0.6 4.2
Retracted s 2.5 ±0.6 3.4
Bucket Extended s 3.1 ±0.6 4.0
Retracted s 2.2 ±0.6 3.0
Dozer Blade Extended s 2.9 ±0.6 3.8
Retracted s 2.3 ±0.6 3.1
Offset Extended s 3.5 ±0.6 4.5
Retracted s 2.6 ±0.6 3.5

II-17 TB53FR
SPECIFICATIONS STANDARDS FOR JUDGING PERFORMANCE

Serial Number 15810005~

Item Unit Standard Values Allowable Values
Cylinders
Natural Cylinder Drop
Boom mm 10 20
Arm mm 6 12
Bucket mm 5 10
Dozer Blade mm 5 10
Offset mm 5 10
Bucket Tip mm 125 500
Levers
Lever Operating Force
Boom Raise N 11.8 ±3.9
Lower N 8.8 ±3.9
Arm Dump N 11.8 ±3.9
Load N 8.8 ±3.9
Bucket Dump N 11.8 ±3.9
Load N 8.8 ±3.9
Slew Right N 11.8 ±3.9
Left N 8.8 ±3.9
Travel N 22.6 ±9.8
Dozer Blade N 37.3 ±9.8
Offset N 41.8 ±9.8
Lever Play
Boom mm 4
Arm mm 4
Bucket mm 4
Slew mm 4
Travel mm 40
Dozer Blade mm 15
Slew Bearing
Backlash mm 20 ±13 73
Slew Bearing Play mm 0.6 ±0.5 2.0
Crawler
Crawler Tension Steel mm 172~192 
Rubber mm 108~118 

TB53FR II-18
STANDARDS FOR JUDGING PERFORMANCE SPECIFICATIONS
METHODS FOR INSPECTING PERFOR-
MANCE

Hydraulic Oil Pressure (Main Relief Valve Set

Pressure)
Boom, Arm
Measuring Method P2 P1
• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Mount the pressure gauge on the pressure detec- P3
tion port, operate the desired hydraulic circuit
and measure the relief pressure.

J1B005

Pressure Detection Port R1

Circuit Relief Valve
Port Position Size
Boom P1 G1/4 R1
Arm P2 G1/4 R2

R3 R2 J1B006

Adjusting Method
1. Loosen locknut (2), then begin adjusting pressure
by turning setting screw (1).
Turning clockwise ................ raises the set pressure.
Turning counterclockwise .... lowers the set pressure.
2. In order to keep the setting screw from turning
after pressure has been adjusted, tighten the lock-
nut while at the same time holding the setting
screw firmly in place.
3. Operate the relief valve once more to confirm that
the pressure that has been set it stabilized.

II-19 TB53FR
SPECIFICATIONS STANDARDS FOR JUDGING PERFORMANCE

Dozer Blade
Measuring Method P2 P1
• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Mount the pressure gauge on the pressure detec-
P3
tion port, operate the desired hydraulic circuit
and measure the relief pressure.

Pressure Detection Port

Circuit Relief Valve
Port Position Size
Dozer Blade P3 G1/4 R3 J1B005

R1

R3 R2 J1B006

Adjusting Method
1. Loosen locknut (2), then begin adjusting pressure
by turning setting screw (1).
Turning clockwise ................ raises the set pressure.
Turning counterclockwise .... lowers the set pressure.
2. In order to keep the setting screw from turning
after pressure has been adjusted, tighten the lock-
nut while at the same time holding the setting
screw firmly in place.
3. Operate the relief valve once more to confirm that
the pressure that has been set it stabilized.

TB53FR II-20
STANDARDS FOR JUDGING PERFORMANCE SPECIFICATIONS
Hydraulic Oil Pressure (Slewing Relief Valve
Set Pressure) P2 P1
Measuring Method
• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
P3
• Mount the pressure gauge on the pressure detec-
tion port and set a solid obstacle so that the
upperstructure cannot slew in the direction to be
measured. Next, operate the circuit to be mea-
sured and measure the relief pressure.

Pressure Detection Port

Circuit Relief Valve J1B005
Port Position Size
Right Slew R1
P3 G1/4
Left Slew R2
R1
R2

Adjusting Method 2
1
1. Loosen locknut (2), then begin adjusting pressure
by turning setting screw (1).
Turning clockwise ................ raises the set pressure.
Turning counterclockwise .... lowers the set pressure.
2. In order to keep the setting screw from turning
after pressure has been adjusted, tighten the lock-
nut while at the same time holding the setting
screw firmly in place. J1B007
3. Operate the relief valve once more to confirm that
the pressure that has been set it stabilized.

II-21 TB53FR
SPECIFICATIONS STANDARDS FOR JUDGING PERFORMANCE

Hydraulic Oil Pressure (Pilot Relief Valve Set

Pressure)
Measuring Method
• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60˚C
P4
• Mount pressure gauge on the pressure detection
port and measure the pilot relief pressure.

Pressure Detection Port

Relief Valve
Port Position Size
P4 G1/4 R4

J1B008

Adjusting Method
1. Loosen locknut (2), then begin adjusting pressure
by turning setting screw (1).
Turning clockwise ................ raises the set pressure. 2
Turning counterclockwise .... lowers the set pressure. 1
2. In order to keep the setting screw from turning
after pressure has been adjusted, tighten the lock-
nut while at the same time holding the setting
screw firmly in place.
3. Operate the relief valve once more to confirm that
the pressure that has been set it stabilized. R4

J1B009

TB53FR II-22
STANDARDS FOR JUDGING PERFORMANCE SPECIFICATIONS
Travel Speed (5 Revolutions)
• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Measurement Posture : Excavator body raised
using both hoe attachment and dozer blade.
• Set crawler belts in motion. Starting after one
full revolution, measure the time required for 5
revolutions. (To measure speed after it has sta-
bilized.)

Travel Speed (10m)

• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Measurement Posture : Travel Posture
• Set excavator in motion. Starting after a distance MEASURED
APPROACH
of 5 meters, measure the time required to travel STRETCH
START
10 meters. Do this on level ground.

■ Travel Posture
Fully extend the arm and bucket cylinders and
adjust the hoe attachment so that its lowest part
is even with the excavator’s minimum ground
clearance level. The hoe attachment, of course, MIN. GROUND
should be in a no-load state and the dozer blade CLEARANCE
should not be touching the ground.

Travel Curve
• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Measurement Posture : Travel Posture
• Starting after an approach of 5 meters, drive the
excavator in a turn for 10 meters, then measure
the distance of X (5 m point). Do this on level
ground.

II-23 TB53FR
SPECIFICATIONS STANDARDS FOR JUDGING PERFORMANCE

Natural Travel Drop

• Engine : Stopped
• Hydraulic Oil Temp. : 50~60°C
• Gradient : 15°
• Measurement Posture : Fully extend the boom,
arm and bucket cylinders and completely retract
the dozer blade cylinder.
• With the excavator parked at angle for 5 min-
utes, measure the extent of natural drop.

Slew Time
• Engine : Rated r.p.m. BUCKET PIN BOOM FOOT PIN
• Hydraulic Oil Temp. : 50~60°C
• Measurement Posture : Completely retract the
arm cylinder, fully extend the bucket cylinder
and adjust so that boom foot pin and bucket pin
are at matching height. Rest the dozer blade on
the ground.
• With the hoe attachment in a no-load state, wait
1 rotation, then measure the time required for
the next 2 rotations.

Overrun When Slewing Stops

• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Measurement Posture : Same as that for mea-
suring slew time. LEVER BACK
START TO NEUTRAL
• Draw matching marks on the outer race of the
slew bearing and lower frame at an exactly 180 OVER RUN
degrees rotation from the starting point. With
the hoe attachment in a no-load state, rotate 180
degrees at, which point return the operation
lever to neutral. Measure the differential be-
tween the position marks and the point the hoe
attachment stops.

Natural Slew Drop

TION
• Engine : Stopped DEVIA
• Hydraulic Oil Temp. : 50~60°C
• Gradient : 15°
• Measurement Posture : Same as that for mea-
suring slew time.
• Rotate the upper machinery so that it is directly
abeam of the grade, then draw positional marks
on the slew bearing’s outer race and the lower
frame. Then measure the distance that develops
between the marks after 5 minutes.

TB53FR II-24
STANDARDS FOR JUDGING PERFORMANCE SPECIFICATIONS
Boom Cylinder Speed
• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Measurement Posture : Completely retract the
arm cylinder, fully extend the offset cylinder,
fully extend the bucket cylinder and rest the
dozer blade on the ground.
• Then measure the time required for the bucket to
reach its highest elevation point (lowest point)
from its lowest point (highest point) resting on
the ground. (Do not include the cushioning
time.)

Arm Cylinder Speed

• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Measurement Posture : Completely retract the
arm cylinder, fully extend the bucket cylinder,
position the arm horizontally and rest the dozer
blade on the ground.
• Then measure the time required for the arm
cylinder to completely retract (extend) from a
fully extended state (retracted state).

Bucket Cylinder Speed

FULLY
• Engine : Rated r.p.m. RETRACTED
• Hydraulic Oil Temp. : 50~60°C
• Measurement Posture : Completely retract the
arm cylinder, position the arm horizontally and
rest the dozer blade on the ground.
• Then measure the time required for the bucket
cylinder to completely retract (extend) from a
fully extended state (retracted state). FULLY EXTENDED

Dozer Blade Cylinder Speed

• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Measurement Posture : Using the hoe attach-
ment, lift up the dozer blade end of the excava-
tor.
• Then, raising and lowering the dozer blade full
stroke, measure the time required per stroke in
each direction.

II-25 TB53FR
SPECIFICATIONS STANDARDS FOR JUDGING PERFORMANCE

Offset Cylinder Speed

• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Measurement Posture : Same as that for mea-
suring slew time.
• While swinging the boom left (right) to right
(left), measure the time required for a full stroke
each way.
(Do not include the cushioning time.)

L2B022

Natural Cylinder Drop

Boom, Arm, Bucket, Dozer Blade, Bucket Tip
• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Measurement Posture : Completely retract the
dozer blade and arm cylinders, fully extend the
bucket cylinder and adjust the bucket pin posi-
tion to the same height as the boom foot pin.
• Maintain this position for 10 minutes, then mea-
sure the change in rod length and the distance the
bucket tip falls.

Offset Cylinder
• Engine : Stopped
• Hydraulic Oil Temp. : 50~60˚C
• Gradient : 15˚
• Measurement Posture : Same as that for mea-
suring slew time.
• Rotate the upper machinery so that it is directly
abeam of the grade, then measure the change in
rod length after 5 minutes.

L2B023

TB53FR II-26
STANDARDS FOR JUDGING PERFORMANCE SPECIFICATIONS
Lever Operating Force
• With the engine stopped, attach a push-pull
scale to the center of the operation lever’s handle
grip, or in the case of a pedal, position a push-
pull scale to its tip and record the measurement
at the point the lever/pedal reaches full stroke.

Lever Play
• Measure any discernible play at the tip of the
lever (pedal).

Backlash
• Measurement Posture : Completely retract the
arm cylinder and fully extend the bucket cylin-
der.
• Move the tips of the bucket teeth from side to
side (left and right) and measure the play.

Slew Bearing Play

1. Attach a dial gauge to the bot- 2. Raise the crawler on one side 3. Then raise the opposite
tom face of the slew bearing’s off the ground and set the dial crawler and read the dial
race located near the front of gauge to zero. gauge.
the upper machinery.

II-27 TB53FR
SPECIFICATIONS STANDARDS FOR JUDGING PERFORMANCE

Crawler Tension
• Raise the excavator completely off the ground
using the hoe attachment and dozer blade.
Then measure the distance (of droop) between
the center point on the crawler frame and top of
the crawler shoe.
Note: For the rubber crawler, the measuring
should be performed after placing the
joint portion with “M” mark to the top
center.

TB53FR II-28
III . MACHINE CONFIGURATION

II-29
III-1 TB53FR
MACHINE CONFIGURATION

CONTENTS

Drive System ......................................................................................................................................................... 3

Slew System .......................................................................................................................................................... 9
Travel System ...................................................................................................................................................... 11
Upper Frame ........................................................................................................................................................ 17
Control System .................................................................................................................................................... 23
Attachments ......................................................................................................................................................... 29
Hydraulic System ................................................................................................................................................ 35
Electrical System ................................................................................................................................................. 39
Interference Prevention System ........................................................................................................................... 43

TB53FR II-30
III-2
DRIVE SYSTEM MACHINE CONFIGURATION
DRIVE SYSTEM
DISASSEMBLY AND ASSEMBLY 

Removing the Engine

1. Disconnect the battery ground cable (1) from the
battery.

2. Remove the engine hood and side cover.

“Removing the Covers”

3. Remove the counterweight. ."+$

“Removing the Upper Frame”

2
10 11
4. Tilt up the floor frame.

4
5. Remove the radiator and oil cooler. 7
“Removing the Radiator and Oil Cooler”

8
6. Disconnect the air hose (2) from the engine.

5 6
7. Disconnect the coolant drain hose (3). 9 J1C101

8. Close the valves (4) and disconnect two heater

hoses.

9. Disconnect the fuel hoses (5) and (6) from the

engine.

12
17
10. Disconnect the fuel hoses (8) from water separa-
tor (7). 17
3
J1C102

11. Disconnect the electric wiring to the feed pump (9).

12. Remove the filler cap (10) from the bracket (11).
• Remove the filler cap with hose attached and
put it on the fuel tank.
16

13. Remove the water separator (7) and the feed

pump (9) together with the bracket (11).

14
14. Remove the hydraulic pump. 17
“Removing the Hydraulic Pump” 15 J1C103

III-3 TB53FR
MACHINE CONFIGURATION DRIVE SYSTEM

15. Disconnect the accelerator wire (12) from the

engine.

16. Disconnect the battery cable and all the connec-

tions on the engine side of the electric wirings
(14).
• Attach identification labels to individual wir-
ings for correct reassembling.
• Disconnect the wirings from the clamps and
the bands.

17. Disconnect the engine ground cable (15).

18. Disconnect the exhaust pipe (16).

19. Remove the cushion rubber tightening double

nuts (17) and the engine assembly.

Installing the Engine

Follow the same procedure as for removal in the
reverse order.

TB53FR III-4
DRIVE SYSTEM MACHINE CONFIGURATION
Removing the Radiator and Oil Cooler
1. Remove the engine hood, and side cover.
“Removing the Covers”

2. Remove the counterweight.

“Removing the Upper Frame”

3. Tilt up the floor frame.

1
4. Remove the hydraulic tank.
“Remove the Hydraulic Tank”

5. Loosen the drain cock (1) to drain the engine

coolant. J1C104

• Coolant volume: Approx. 7.2 L

5 11
6. Disconnect the coolant drain hose (2).

7. Remove the exhaust pipe (3).

8. Disconnect the hose from sub tank (4).

4
9. Remove the bolts and plates from the bracket (5).
6 10
10. Remove the bolts and the bracket (5).

11. Disconnect the radiator hoses (6) and (7).

1 2 3 J1C105

12. Disconnect the 2 oil cooler hoses.

• Prepare a plate to catch drips of the hydraulic 5
oil. 9 7
8
13. Remove the fan guard (8).

14. Remove the brackets and fan ring (9).

15. Remove the cushion rubber tightening double

nuts (10).

16. Suspend the radiator (11) and oil cooler together

with the bracket, and remove them carefully
without touching other parts. J1C106

a. Pull up the radiator and oil cooler together with

the bracket about two to three centimeters to
remove them from the cushion rubbers.
b. Slide them to the front to prevent the shroud
from hitting the cooling fan.
A

Installing the Radiator and Oil Cooler

Follow the same procedure as for removal in the
reverse order.
• The radiator should be mounted at right angles to B
the main body frame and parallel to the cooling fan.
A: parallel
B: right angle L2C114

III-5 TB53FR
MACHINE CONFIGURATION DRIVE SYSTEM

Removing the Hydraulic Pump

1. Remove the engine hood. 4 3
“Removing the Covers”

2. Remove the counterweight.

“Removing the Upper Frame”

3. Tilt up the floor frame.

6
4. Disconnect the air hose from the engine.
5
5. Drain out the oil from the hydraulic tank.
“Removing the Hydraulic Tank” 1
2
J1C107

6. Disconnect the electric wiring to the solenoid

valve (1).

7. Disconnect the suction hose (2) from the pump.

8. Disconnect the discharge hoses (3), (4) and (5)

from the pump (6).

9. Disconnect the 3 discharge hoses from the sole-

noid valve (1).

10. Remove the fixing bolts and take out the hydrau-
lic pump (6).
Bolt: 102 N·m
• Apply molybdenum disulfide grease to the
spline section.

Installing the Hydraulic Pump

Follow the same procedure as for removal in the
reverse order. 7

Cautions when starting the hydraulic pump

1. Fill the pump housing with clean hydraulic oil
before starting the pump.
• Loosen the air release plug (7), fill in the oil
through the opening until the oil overflows,
and fasten the plug.

2. After starting the engine, let it run at a low idling

speed for a while to completely bleed out the air
within the circuit. J1C108

TB53FR III-6
DRIVE SYSTEM MACHINE CONFIGURATION
Removing the Fuel Tank
1. Remove the counterweight.

2. Tilt up the floor frame.

3. Loosen the drain plug (1) to drain out the fuel.

2
• Fuel tank capacity: 75 L

4. Disconnect the battery ground cable (2) from the

fuel tank (3). 3
4 7
1
5. Disconnect the fuel hoses (4), (5), (6) and (7)
5
from the fuel tank.
8 6 J1C109

6. Disconnect the electric wiring (8) from the fuel

tank (3).

7. Suspend the fuel tank (3) temporarily and remove

the 4 fixing bolts.
• Remove 2 bolts from the upper part of the tank.
• Remove 2 bolts from the lower part of the tank.

8. Suspend the fuel tank (3) and remove it.

• Suspend the tank by sliding it to avoid hitting
the floor frame.
Fuel tank: 32 kg

Installing the Fuel Tank

Follow the same procedure as for removal in the
reverse order.

III-7 TB53FR
MACHINE CONFIGURATION DRIVE SYSTEM

TB53FR III-8
SLEW SYSTEM MACHINE CONFIGURATION
SLEW SYSTEM
DISASSEMBLY AND ASSEMBLY

Removing the Slew Motor

1. Tilt up the floor frame.
2
2. Loosen the drain plug and drain the hydraulic
1
tank.
“Replacing hte Hydraulid Oil” 4
6
3. Disconnect the hydraulic hoses (1), the low pres- 3
5
sure hose (2) and control cables from control
valve (3). J1C202

• Attach ID labels to the various hoses for when

reassembling them.

4. Disconnect the hydraulic hoses (4) from shuttle 5

valve (5).
• Attach ID labels to the various hoses for when 7
reassembling them.

5. Remove the bolts from bracket (6).

6. Remove the control valve and the shuttle valve

together with bracket (6).

7. Disconnect 6 hydraulic hoses from the slew mo- 8 J1C203

tor (7).

8. Remove the slew motor fixing bolts (8).

Bolt: 256 ±12.7 N·m
• Apply thread lock to the bolts.

9. Suspend the slew motor (7) and remove it.

Slew motor: 56 kg

Installing the Slew Motor

Follow the same procedure as for removal in the
reverse order.

III-9 TB53FR
MACHINE CONFIGURATION SLEW SYSTEM

Removing the Slew Bearing

1. Remove the hoe attachment.
“Attachments, Disassembly and Assembly”

2. Remove the upper frame.

“Removing the Upper Frame”

3. Remove the inner race fixing bolts.

Bolt: 256 ±12.7 N·m
• Apply thread lock to the bolts.

4. Suspend the slew bearing and remove it.

Slew bearing: 84 kg

Installing the Slew Bearing

GREASE APPLYING HOLE
Follow the same procedure as for removal in the
reverse order.
• When mounting the slew bearing on the upper
frame, be sure to position the reamer bolts and the
grease holes as illustrated in the right figure.
• Apply grease to the inner teeth of the slew bearing. FRONT
REAMER BOLT

J1C204

Removing the Swivel Joint

1. Remove the upper frame.
“Removing the Upper Frame”

2. Disconnect the hoses (1) from the hub side.

• Make a mark on the hoses at the position of
connection.

3. Remove the installation bolts (2), then remove

the swivel joint (3).
Bolt: 102 ±5.1 N·m
• Apply thread lock to the bolts.
Swivel Joint: Approx. 22 kg ."+ $

Installing the Swivel Joint 4

Follow the same procedure as for removal in the
reverse order.
• When mounting the swivel joint, tighten it tempo-
rarily with the fixing bolts, and center the swivel
joint by using a dial gauge (4).
• Adjust the centering so that the deviation from the
center is within 0.25 mm.

L2C207

TB53FR III-10
TRAVEL SYSTEM MACHINE CONFIGURATION
TRAVEL SYSTEM
1
DISASSEMBLY AND ASSEMBLY
4
Removing the Rubber Crawler
1. Loosen the tension of the crawler (1).
When loosening the check valve (2), turn it slowly. 2
Do not loosen it beyond the point where grease
starts to ooze out. If it is difficult for the grease to
come out, move the machine forward and in
reverse.
Check valve:177 N·m C4C308

2. Raise the body and after engaging pieces of iron

pipe (3) in the crawler, rotate the sprocket in the
reverse direction.

3. When the iron pipes reach a point just to the side

of the idler (4), stop rotating the sprocket.

4. Slide the crawler to the side to remove it.

Rubber crawler: 219 kg

Installing the Rubber Crawler

1. Raise the machine body and set the crawler (1) on
the frame.
• The Crawler should engage in the sprocket.

2. Engage pieces of iron pipe (3) in the crawler, then

rotate the sprocket in the reverse direction.

3. When the iron pipes reach a point just to the side

of the idler, stop rotating the sprocket.

4. Slide the crawler to a position where it will fit

snugly with the idler.

5. Engage the crawler fully with the sprocket and the

idler, then adjust the crawler tension.
“II. Specifications, Standards for Judging
Performance”

III-11 TB53FR
MACHINE CONFIGURATION TRAVEL SYSTEM

Removing the Steel Crawler

1. Stop the machine so that master pin is front of the
idler.

2. Loosen the tension of the crawler (1). 2

When loosening the check valve (2), turn it slowly. 3
Do not loosen it beyond the point where grease
starts to ooze out. If it is difficult for the grease to
come out, move the machine forward and in 1
reverse.
Check valve: 177 N·m C4C309

3. Take out the master pin (3) and separate the ends
of the crawler (1).

4. Raise the body, then open up the crawler (1) while

running the travel motor slowly in reverse.
• Use the dozer blade and hoe attachment to
raise the body, It should be kept level as it is
raised.
Steel Crawler: 245 kg

Installing the Steel Crawler

1. Raise the body and position the crawler beneath
the frame.
• Be careful not to mistake the installation direc-
tion of the crawler.

2. Engage the links in the sprocket, then run the

travel motor slowly in the forward direction to
wrap the crawler around the frame.

3. After lowering the body, install the master pin to

join the ends of the crawle.
• After aligning the pin holes, insert a temporary
pin before inserting the master pin.

4. Raise the body and adjust the crawler tension.

“II, Specifications, Standards for judging
performance”

TB53FR III-12
TRAVEL SYSTEM MACHINE CONFIGURATION
Removing the Carrier Roller
1. Loosen the tension in the crawler belt.

2. Using a hydraulic jack, push up the crawler belt.

3. Loosen the installation nut (3) and remove the

bolt, then remove the upper roller (4).

3
Installing the Carrier Roller
Follow the procedure used to remove the upper roller
in reverse order.
• When tightening the installation nut, apply 4
G4C307
thread lock to the threads.
Installation nut: 256 ±12.7 N·m

Removing the Track Roller

1. Loosen the crawler tension.

2. Loosen the roller installation bolt (1) slightly

(approximately 1 turn).
1 2
3. Raise the machine body, take out the installation
bolt (1) and remove the roller (2).

Installing the Track Roller

1. Tighten the roller (2) installation bolt (1) tempo-
rarily. J1C309

2. Bring the machine body in full contact with the

ground, then tighten the bolt.
Bolt: 102 ±5.1 N·m
• Apply thread lock to the threads of the bolt.

3. Raise the machine body, then adjust the tension of

the crawler.
Raise the machine body, then adjust the tension of
the crawler.

III-13 TB53FR
MACHINE CONFIGURATION TRAVEL SYSTEM

Removing the Idler and Track Adjuster

1. Remove the Crawler.
“Removing the Crawler”

2. Take out the idler and track adjuster.

Idler + Track adjuster: 66.2 kg

Installing the Idler and Track Adjuster

Follow the procedure used for removal in reverse
order.
• Apply grease to the rubbing surfaces of the track
adjuster piston and cylinder.

Removing the Travel Motor

1. Remove the crawler.
“Removing the Crawler”

2. Remove the installation bolts (1) and remove the

sprocket (2).
Bolt: 155.9 ±7.7 N·m
• Apply thread lock to the bolts.

3. Remove the motor cover and disconnect the hy-

draulic piping (4).

4. Suspend the travel motor (3) temporarily and F4C303

remove the fixing bolts (5).

Bolt: 155.9 ±7.7 N·m 4
• Apply thread lock to the bolts.

5. Suspend the travel motor (3) and remove it.

Travel motor: 57 kg

Installing the Travel Motor

Follow the procedure used for removal in reverse
order. 4

5 G4C309

TB53FR III-14
TRAVEL SYSTEM MACHINE CONFIGURATION
Replacing the Rubber Crawlers with the Steel
Crawlers
Supplementary Parts
Item Part Number Description Quantity
3 03913-00400 SPACER 20
4 11010-51255 BOLT 40
5 04610-00700 GUIDE 4
6 11010-41230 BOLT 12
7 11400-20012 WASHER 12

WARNING
If you must work beneath the raised machine or
equipment, always use wood blocks, jack-stands
or other rigid and stable supports. Never get 3
under the machine or working equipment if they
are not sufficiently supported.

Refer to the previous pages for removing and install-

ing the crawler belts.
1. Remove the track roller.
“Removing the Track Roller” 4
J1C310

2. Fit the track roller with the spacer (3) added

between the frame and the roller bracket.
“Installing the Track Roller”

3. Attach the guide (5) to the bottom of the frame on

the idler side, and fix them with a washer (7) and
a bolt (6).
5

6 5

J1C311

III-15 TB53FR
MACHINE CONFIGURATION TRAVEL SYSTEM

TB53FR III-16
UPPER FRAME MACHINE CONFIGURATION
UPPER FRAME
DISASSEMBLY AND ASSEMBLY

Removing the Upper Frame

1. Remove the hoe attachment. 1
“Attachments, Disassembly and Assembly”

2. Remove the cab.

“Removing the Cab”

3. Remove the engine hood and side cover.

“Removing the Covers”
L2C405

4. Take out the bolts and remove the counterweight

(1).
Counterweight: 620 kg

5. Disconnect the 8 hydraulic hoses (2) from the 2

swivel joint (3).
• Make match marks on the installation position
of the hoses before disconnecting them.

6. Take out the fixing bolts and remove the stopper.

Bolt: 102 ±5.1 N·m 3
• Apply thread lock to the bolts.

7. Disconnect the grease pipe (5) from the slew L2C406

bearing.

8. Remove the fixing bolts (4) from the outer race of

the slew bearing, leaving only two bolts each on
the front and the rear of the machine.
• When mounting the slew bearing, be careful of
the positions of the grease hole and reamer
bolts.
“Installing the Slew Bearing”
Bolt: 102 ±5.1 N·m
• Apply molybdenum disulfide grease to the
threads and the bolt holes.
5
9. Suspend the upper frame temporarily and remove J1C405

the remaining fixing bolts while keeping the

frame well balanced.

10. Suspend the upper frame and remove it.

L2C407

III-17 TB53FR
MACHINE CONFIGURATION UPPER FRAME

Installing the Upper Frame

Follow the same procedure as for removal in the
reverse order.

L2C408

TB53FR III-18
UPPER FRAME MACHINE CONFIGURATION
Removing the Floor Frame
1. Disconnect the battery ground cable (1).

2. Remove the cab.

“Removing the Cab”

3. Disconnect the accelerator wire (2) on the engine

side.
• After disconnecting the wire end from the wire
stopper, loosen the fastening nut and take it out 2
of the bracket.

4. Tilt up the floor and engage the safety stopper (3).

J1C406

5. Disconnect the hydraulic hoses (4), connected to

the right and left pilot valves, on the side of the 7 9
control valves.
6 10 4
• For reassembling, be sure to attach the identi-
fication labels to individual hydraulic hoses.
5
6. Disconnect the two control cables (5) connected
to the travel levers. 3 1

7. Disconnect the electric wiring (6) for travel speed 8

switching.

8. Disconnect the hydraulic hose (7) connected to

the lock cylinder. J1C407

9. Disconnect the electric wirings (8) and (9), con-

nected to the right and left lever stands, on the side
of the engine.
11
10. Suspend the floor frame temporarily and remove
the three stay dampers (10).

11. Disengage the safety stopper (3) and lower the

floor frame.

12. Remove the bolt and the shaft (11).

13. Suspend the floor frame and remove it. L2C412

Installing the Floor Frame

Follow the procedure used for removal in reverse
order.

III-19 TB53FR
MACHINE CONFIGURATION UPPER FRAME

Removing the Covers

1. Remove the engine hood (1). 1
a. Open the engine hood and suspend it tempo-
rarily.
b. Remove the hinge fixing bolts (2). 3

2. Take out the 3 caps and the bolts and remove the
side cover (3).
2
3. Take out the 5 bolts and remove the center cover
(4).

F4C409

Installing the Covers

Follow the same procedure as for removal in the
reverse order. 4

J1C408

TB53FR III-20
UPPER FRAME MACHINE CONFIGURATION
Removing the Cab
1. Disconnect the battery ground cable from the
battery.
1
2. Disconnect the electric wiring (1) for the cab.

3. Remove the castle nuts on the 2 front positions

(A).

4. Remove the castle nuts on the 2 rear positions (B).

a. Remove the fixing bolts and the cover (2).
b. Remove the castle nuts.

5. Suspend the cab and remove it. L2C416

Cab: 185 kg

A A

L2C417

B 3 2 B

L2C418

Installing the Cab

Follow the same procedure as for removal in the
reverse order.
• Be sure to mount the fixing bolts and cushion
rubber on the frame in advance.
• Suspend the cab on the level and fix it in the
temporarily suspended state.

L2C419

III-21 TB53FR
MACHINE CONFIGURATION UPPER FRAME

TB53FR III-22
CONTROL SYSTEM MACHINE CONFIGURATION
CONTROL SYSTEM
Hydraulic Pilot Unit
A Type (ISO) – 1/2

5 1

R4
RP
R1
R3
RT
R2

4
2
A1
A2
L4
LP L1
A7 L3
LT
A8 L2

B2 P B1
A2

P1
B2 6
WA
3 B7
WB WA
B8
WD
WC
WC
WB

SH
7

J1C501

♦ Table of Connections ♦
R1 ↔ B1 WB ↔ A8
Control Valve
R2 ↔ A2 Control Valve Shuttle Valve WC ↔ B8
R3 ↔ A1 WD ↔ SH Slew Motor
R4 ↔ A2
Solenoid Valve
RP ↔ P 1. Right Pilot Valve
Tank 2. Left Pilot Valve
RT ↔ T
Pilot Valve 3. Solenoid Valve
L1 ↔ WB Shuttle Valve 4. Control Valve
L2 ↔ B7 Control Valve 5. Hydraulic Tank
6. Shuttle Valve
L3 ↔ WC 7. Slew Motor
Shuttle Valve
L4 ↔ WA
LP ↔ P1 Control Valve
LT ↔ T Tank
Solenoid Valve B2 ↔ B2
Control Valve
Shuttle Valve WA ↔ A7

III-23 TB53FR
MACHINE CONFIGURATION CONTROL SYSTEM

A Type (ISO) – 2/2

4
B 3 A5 A6
A

P
2
B1

T
A1
B5

B6
P1

P1

PA

PG
PB1
PB2
Dr

PG
1

OT P
X 8 G 6

X
OP
OR LC

OL

7
J1C502

♦ Table of Connections ♦
OR ↔ B5 Control Valve 1. Pilot Valve (Offset)
Pilot Valve OL ↔ A1 Solenoid Valve 2. Pump
OP ↔ LC Lock Cylinder 3. Solenoid Valve
(Offset)
4. Control Valve
OT ↔ T Tank 5. Hydraulic Tank
PB2 ↔ PG Slew Motor 6. Slew Motor
7. Lock Cylinder
Pump PB1 ↔ P1 Control Valve
8. Swivel Joint
PA ↔ P Swivel Joint
B ↔ A6
Control Valve
A ↔ B6
Solenoid Valve
T ↔T Tank
B1 ↔ A5 Control Valve
Slew Motor Dr ↔ T Tank
Swivel Joint G ↔T Tank
Control Valve P1 ↔ P Solenoid Valve
Slew Motor PG ↔ OP Pilot Valve (Offset)

TB53FR III-24
CONTROL SYSTEM MACHINE CONFIGURATION
A Type (ISO) ↔ G Type (JCB) – 1/2

5
1

R4
RP
R1
R3
RT
R2

4 2
A1
A2
L4
LP L1
A7 L3
LT
A8 L2

B2 P B1
A2

B2 P1
6
WA
B7
3 WB WA
B8
WD
WC
S3 WC
SD
WB

SA SB
S4

S2

8
S1 SC SH

J1C503

♦ Table of Connections ♦
R1 ↔ B1 Control Valve Selector Valve
R2 ↔ S3 Selector Valve Position Position
R3 ↔ A1 Control Valve A Type (ISO) G Type (JCB)
R4 ↔ S4 Selector Valve Right Pilot Valve
RP ↔ P Solenoid Valve Front Lower Dump
Boom Arm
RT ↔ T Tank Rear Raise Load
Pilot Valve
L1 ↔ WB Shuttle Valve Left Load Load
Bucket Bucket
L2 ↔ S1 Selector Valve Right Dump Dump
L3 ↔ WC Shuttle Valve Left Pilot Valve
L4 ↔ S2 Selector Valve Front Dump Lower
Arm Boom
LP ↔ P1 Control Valve Rear Load Raise
LT ↔ T Tank Left Left Left
Slew Slew
SC ↔ A2 Control Valve Right Right Right
SD ↔ A2 Solenoid Valve
Selector Valve
SA ↔ B7 Control Valve
SB ↔ WA Shuttle Valve
WA ↔ A7 1. Right Pilot Valve 5. Hydraulic Tank
2. Left Pilot Valve 6. Shuttle Valve
WB ↔ A8 Control Valve
Shuttle Valve 3. Solenoid Valve 7. Slew Motor
WC ↔ B8 4. Control Valve 8. Selector Valve
WD ↔ SH Slew Motor
Solenoid Valve B2 ↔ B2 Control Valve

III-25 TB53FR
MACHINE CONFIGURATION CONTROL SYSTEM

A Type (ISO) ↔ G Type (JCB) – 2/2

4
B 3 A5 A6
A

P
2
B1

T
A1
B5

B6
P1

P1

PA

PG
PB1
PB2
Dr

PG
1

OT P
X 8 G 6

X
OP
OR LC

OL

7
J1C502

♦ Table of Connections ♦
OR ↔ B5 Control Valve 1. Pilot Valve (Offset)
Pilot Valve OL ↔ A1 Solenoid Valve 2. Pump
OP ↔ LC Lock Cylinder 3. Solenoid Valve
(Offset)
4. Control Valve
OT ↔ T Tank 5. Hydraulic Tank
PB2 ↔ PG Slew Motor 6. Slew Motor
7. Lock Cylinder
Pump PB1 ↔ P1 Control Valve
8. Swivel Joint
PA ↔ P Swivel Joint
B ↔ A6
Control Valve
A ↔ B6
Solenoid Valve
T ↔T Tank
B1 ↔ A5 Control Valve
Slew Motor Dr ↔ T Tank
Swivel Joint G ↔T Tank
Control Valve P1 ↔ P Solenoid Valve
Slew Motor PG ↔ OP Pilot Valve (Offset)

TB53FR III-26
CONTROL SYSTEM MACHINE CONFIGURATION
INSPECTION AND ADJUSTMENT

Adjusting Stroke
Adjust the lever’s stroke to correspond to the control
valve spool stroke using the setscrew.

1. The spool of the control valve (1) should be in the

neutral position.
2. Position lever (3) at the center of the stroke by
turning nut (2), then fasten the control cable (4)
with nut (5).
3. Move the lever (3) and hold it at the stroke end of
the valve spool.
4. Set the setscrew (6).

III-27 TB53FR
MACHINE CONFIGURATION CONTROL SYSTEM

TB53FR III-28
ATTACHMENTS MACHINE CONFIGURATION
ATTACHMENTS
DISASSEMBLY AND ASSEMBLY

General Cautions
• When disconnecting hydraulic hoses, be sure to Air Bleeding Operation
bleed off any residual pressure in the hoses and in 1. Start the engine and let it idle for about 5 minutes.
the Hydraulic Tank. 2. With the engine running at slow speed, extend
• Plug openings which are opened up when piping is and retract the cylinders 4 or 5 times.
disconnected to prevent dust and mud, etc. from • Move the piston rods to a position 100 mm
getting in. before the end of the stroke, taking care not to
• During assembly, be sure to adjust all the parts with allow any relief whatsoever.
shims so that there will be no looseness in the 3. Perform the operation in (2) with the engine at top
mounts. speed, then with the engine at slow speed, move
• When aligning pin hole positions, absolutely do the piston rods to the stroke end, allowing relief.
not insert a finger in any pin holes.
• When all the hydraulic equipment such as hydrau-
lic cylinders and piping have been removed and the
hydraulic cylinders are being operated for the first
time after reassembly, be sure the bleed the air out
of the hydraulic circuits by the following proce-
dure.
• Keep the clearance at the pin connecting section to
0.5 mm or less by using the shim. 0.5~1.0mm L2C601E

Removing the Bucket

• Move the back side of the bucket so that it is down,
then lower it fully to the ground. 1
3
1. Take out the lock bolt (1) and remove the pin (2). 2
1
2. Take out the lock bolt (1) and remove the pin (3).

3. Remove the bucket.

Standard bucket: 97 kg

L2C602

Installing the Bucket

Follow the procedure used for removal in reverse A B
order.
• Position the O-ring at the “A” position on the outer
perimeter of the bucket bush before mounting the
bucket. Upon completion of the mounting, move
the O-ring to the prescribed “B” position.

L2C603

III-29 TB53FR
MACHINE CONFIGURATION ATTACHMENTS

Removing the Link

• Fully retract the bucket cylinder and lower the 6
front end of the arm to the ground.
2
1. Take out the split pin, then remove the castle nut
(1).

2. Suspend the bucket link (2) temporarily and take 1

out the pin (3).
• Place pillow blocks under the bucket cylinder
to support it. 3
• Since the end of the guide link will drop when
the pin is taken out, exercise caution. 5
4
C4C604

3. Take out the pin (4), then remove the guide link L
(5), R (6).

Installing the Link

Follow the procedure used for removal in reverse
order.

Removing the Arm 4

1. Disconnect the hydraulic hoses (1) from the bucket
cylinder (2). Next, disconnect hydraulic hoses 2 1
from the auxiliary ports (3).

2. Suspend the bucket cylinder (2) temporarily, take

out the pin (4) and remove the bucket cylinder.
Bucket cylinder: 34 kg

3. Place pillow blocks under the arm cylinder (5),

then take out the pin (6). 3

G4C602
4. Take out the split pin and remove the castle nut
(7).
5
5. Suspend the arm (8) temporarily, take out the pin
(9) and remove the arm.
Arm mass: 95 kg
6

Installing the Arm 8

Follow the procedure used for removal in reverse
order.
9

7
C4C606

TB53FR III-30
ATTACHMENTS MACHINE CONFIGURATION
Removing the Boom
• Lower the front end of the boom so that it is in full
4
contact with the ground.
1
1. Disconnect the hydraulic hoses (1) from the arm
3
cylinder (3).
9
2. Suspend the arm cylinder (3) temporarily, then
take out the pin (4) and remove the arm cylinder.
Arm cylinder: 44 kg

3. Remove the protector (5) from the boom cylinder 6

(7).
J1C604

4. Disconnect the hydraulic hoses (6) from the boom

cylinder (7).

5. Suspend the boom cylinder (7) temporarily and

take out the pin (8).
• The disconnected end of the cylinder head
should be resting on the ground.
6 8
6. Disconnect the electric wiring to the boom light
(9) and interference sensor (10). 7

7. Disconnect the hydraulic hoses (11) from the

pipes. 5
J1C605

8. Suspend the boom (12) temporarily, take out the

pin (13), pin (14) and remove the boom.
Boom: 227 kg
12
9. Suspend the boom cylinder (7) temporarily, take 10
out the pin (15) and remove the boom cylinder. 13
Boom cylinder: 65 kg
14

15
Installing the Boom 7
Follow the procedure used for removal in reverse
11
order.

J1C606

III-31 TB53FR
MACHINE CONFIGURATION ATTACHMENTS

Removing the Boom Bracket

1. Remove the pin (1) and take out the boom link (2)
from the boom bracket (3). 1
2
16
2. Remove the pin (4) and the link (5).

3. Remove the bolts securing the bracket (6) to the

boom bracket. Then remove the bracket (6) and
the pin (7) in a unit.

4. Remove the fixing bolts and the clamps (8). 4 5

5. Remove the bushing (10) and the guard (11).

3
F4C607

6. Remove the fixing bolts, and disconnect the right

guide (12) and the left guide (13) from the boom
bracket (3). 3

7. Remove the pin (14), and disconnect the offset

cylinder (15) from the boom bracket (3). 7 8

8. Suspend the boom bracket (3) temporarily, and 6

pull out the two pins (16) and remove the boom
bracket (3). 10,14
Boom bracket: 117 kg 11

8
15 L2C611

Installing the Boom Bracket

Follow the same procedure as for removal in the
reverse order.

13

15
12

14
L2C612

TB53FR III-32
ATTACHMENTS MACHINE CONFIGURATION
Removing the Dozer blade
• Lower the dozer blade fully to the ground. 3
2
1. Disconnect the hydraulic hoses (1) from the dozer
blade cylinder (2).
6
2. Suspend the dozer blade cylinder (2) temporarily,
take out the pins (3), (4) and remove the cylinder. 1
Dozer blade cylinder: 44 kg

3. Suspend the dozer blade (5) temporarily, take out

the pins (6), and remove the dozer blade.
Dozer blade: 197 kg 5
4
J1C607

Installing the Dozer Blade

Follow the procedure used for removal in reverse
order.

III-33 TB53FR
MACHINE CONFIGURATION ATTACHMENTS

TB53FR III-34
HYDRAULIC SYSTEM MACHINE CONFIGURATION
HYDRAULIC SYSTEM
HYDRAULIC CIRCUIT DIAGRAM

J1C700

III-35 TB53FR
MACHINE CONFIGURATION HYDRAULIC SYSTEM

TB53FR III-36
HYDRAULIC SYSTEM MACHINE CONFIGURATION
DISASSEMBLY AND ASSEMBLY
1
Removing the Hydraulic Tank
1. Remove the cab.
“Removing the Cab”

2. Remove the covers around the tank.

“Removing the Covers”
7
3. Remove the counterweight.
“Removing the Upper Frame”

4. Remove the cap nut (1) on the air breather, and 2

push the button to release the pressure within the J1C701

tank.
1 5
5. Loosen the drain plug (2) and drain out the oil.
• Tank level capacity: 79 L

6. Disconnect the 3 low pressure hoses (4) from the 4

tank.

7. Disconnect the hydraulic hoses (5) from stop

valve.
8
8. Disconnect the 6 hydraulic hoses (6) from the
tank.
• Attach identification labels to individual hoses 6 J1C702

for correct reassembling.

9. Remove the exhaust pipe fixing bolts (7).

10. Take out the fixing bolts (8), and suspend the tank
and remove it.
Tank: 57 kg

Installing the Hydraulic Tank

Follow the same procedure as for removal in the
reverse order.

III-37 TB53FR
MACHINE CONFIGURATION HYDRAULIC SYSTEM

Filling with Hydraulic Oil

1. Fill the tank with the specified amount of hydrau-
lic oil through the filler inlet.

2. Bleed the air from the hydraulic pump.

“Bleeding the air”

3. Run the engine for 2~3minutes at low speed.

4. Retract the arm and bucket cylinders fully, lower

the boom and lower the bucket to the ground.

5. Lower the dozer blade to the ground.

6. Check if the oil level is proper using a level gauge.

Bleeding the Air

Bleed the air after replacing the hydraulic oil or 7
reassembling hydraulic devices or hoses.
1. Remove the vent plug (7), on the hydraulic pump,
bleed the air from the housing, and tighten plug
(7) once hydraulic oil begins to come out.
• Be sure to stop the engine.

2. Start the engine and run the engine at low idle.

3. Slowly operate the cylinders until the air is bled.

4. Bleed the air from the cylinders. J1C108

a. With the engine running at slow, extend and

retract the cylinders 4 or 5 times.
• Move the piston rods to 100 mm before the
stroke end. DO NOT extend them com-
pletely.
b. Repeat step “a” above with the engine running
at full, then run it at slow and extend the piston
rods completely to the stroke end.

TB53FR III-38
ELECTRICAL SYSTEM MACHINE CONFIGURATION
ELECTRICAL SYSTEM
ELECTRICAL WIRING DIAGRAM

J1C802

III-39 TB53FR
MACHINE CONFIGURATION ELECTRICAL SYSTEM

TB53FR III-40
ELECTRICAL SYSTEM MACHINE CONFIGURATION
Electrical Wiring

25 a b 5
6 4
3
6
28 5
26
4
5
4
2 b c d
c
8
f 8 20
e
24 7 2 c 27
21
2
f a
2 d
1 12 Decel. motor Relay
8 10 Decel. Relay 1
22 9 13
f 8 15
15
f
Decel. Relay 2
19 23
e 15
13
17

f
11 14
15
16
2-Speed Travel Relay 1
18 2-Speed Travel Relay 2

J1C801

1. Main Harness 15. Relay Assembly

2. Diode 16. Relay
3. Fuse (10A) 17. Relay
4. Fuse (15A) 18. Angle
5. Fuse (20A) 19. Wire Harness
6. Fuse (30A) 20. Engine Harness
7. Solenoid Harness 21. Engine Harness
8. Diode 22. Wire
9. Battery Harness 23. Wire
10. Fusible Link 24. Wire
11. Box Assembly 25. Horn
12. Wire Harness 26. Relay
13. Diode 27. Maintenance Light Socket
14. Resistor 28. Rotary Switch

III-41 TB53FR
MACHINE CONFIGURATION ELECTRICAL SYSTEM

TB53FR III-42
INTERFERENCE PREVENTION SYSTEM MACHINE CONFIGURATION
INTERFERENCE PREVENTION SYSTEM
CONSTRUCTION

Interference sensors
Boom switches

11

8 8 C

B
7 5
A

8
4 10
2

D
9 E
F
6

J1C900

A: to decelerate boom raising speed

B: to prevent interference between boom and cab
C: to prevent interference between bucket and cab 1. Switch Box 7. Link Plate
D: Boom deceleration detection position 2. Cover 8. Collar
E: Boom interference detection position 3. Cam Plate 9. Collar
F: Bucket interference detection position 4. Link Plate 10. Spring
5. Collar 11. Switch
6. Rubber Plate

III-43 TB53FR
MACHINE CONFIGURATION INTERFERENCE PREVENTION SYSTEM

Offset switch

2
6 4

B A

F4C901
A: Apply thread-locking compound.
B: Apply molybdenum disulfide grease.
1. Bracket
2. Link plate
3. Roller
4. Collar
5. Offset Switch
6. Spring

TB53FR III-44
INTERFERENCE PREVENTION SYSTEM MACHINE CONFIGURATION
OPERATION
7
The interference prevention system detects the boom
position by the cams (1), (2), and (3), and the boom
switches A, B, and C; and detects the offset arm
position by the angle (4) and the offset switches R and
L. When the attachment enters the interference area,
the solenoids 1, 2, and 3 of the solenoid valve are SOL3

switched by the detected signal to control the spools A R NC

of the boom section (5) and the offset section (6) of the C NO

control valve. Then, the boom cylinder (7) raise is 1

decelerated and stopped, and the left offset of the
4 SOL2
offset cylinder (8) is stopped, thus preventing inter-
B
ference between the attachment and the cab. 2
• Structure and operations of the solenoid valve
C 3 4
SOL1
“IV. Hydraulic Unit, Solenoid Valve”
L
• Switches and solenoids and their functions
- +

Switches R

Boom switch A Decelerates boom raise.

Boom switch B Prevents interference between
boom and cab.
Boom switch C Prevents interference between
bucket and cab. L 5
6
Offset switch R Prevents interference between 1
B L M H

bucket and cab. 2

3 8 R

Offset switch L Prevents interference between L

J1C902
boom and cab.
Solenoids
Solenoid 1 Stops left offset.
Solenoid 2 Stops boom raise.
Solenoid 3 Decelerates boom raise.

III-45 TB53FR
MACHINE CONFIGURATION INTERFERENCE PREVENTION SYSTEM

When the boom is in the small slewing state

When the boom is raised in the right offset state that
will not cause interference between the bucket and the
cab, the interference prevention system will not oper-
ate, and the boom is raised to the top position at a
normal speed.

L2C903

When the boom is in the right offset state

The boom switches A, B, and C are turned off; the
offset switches R and L are turned on; and the sole-
noids 1, 2, and 3 of the solenoid valve are turned on.
The solenoid 1 connects the port A1 and port B1 of the
solenoid valve to supply the pilot pressure to the offset ÒONÓ SOL3

section (6) of the control valve. This enables opera- A2

tion of the right and left offsets. The solenoids 2 and A

R NC
3 connect the ports A2 and B2 to supply the pilot C NO

pressure to the boom section (5) of the control valve. ÒOFFÓ

This will raise the boom to the top position at a normal B2
B ÒONÓ
speed.
ÒOFFÓ L ÒONÓ SOL2
Boom switch A OFF Solenoid 1 ON C
A1 B1
ÒOFFÓ
Boom switch B OFF Solenoid 2 ON ÒONÓ

ÒONÓ SOL1
Boom switch C OFF Solenoid 3 ON
Offset switch R ON - +

Offset switch L ON
R

L 5
R
6
B L M H
1
2
3 R
L
J1C904

TB53FR III-46
INTERFERENCE PREVENTION SYSTEM MACHINE CONFIGURATION
When the boom is in the left offset state
When the offset switch R is turned off by operating
the left offset, the solenoids 1, 2, and 3 are turned off.
At this time, the port B1 and the tank port of the
solenoid valve are connected to shut off the pilot
pressure to be supplied to the offset section (6) of the
control valve. This stops the left offset. ÒOFFÓ SOL3
A2
Boom switch A OFF Solenoid 1 OFF
A
Boom switch B OFF Solenoid 2 OFF R NC
C NO
Boom switch C OFF Solenoid 3 OFF
ÒOFFÓ
Offset switch R OFF B2

Offset switch L ON B ÒOFFÓ

ÒOFFÓ L ÒOFFÓ SOL2

C
B1
ÒOFFÓ ÒONÓ A1

ÒOFFÓ SOL1

- +

B L M H
1 L
2
3
L 5
R
6

R
L
J1C905

When interference between the bucket and

the cab is prevented
Right offset the boom so that the boom becomes
parallel to the body and so that the boom and the cab
will not interfere with each other by providing the
clearance H between them. Then raise the boom to the H
position where the bucket and the cab will not inter-
fere (allow the clearance G between them). F
The clearance G is determined by the boom raise stop E
D
position.

L2C906

III-47 TB53FR
MACHINE CONFIGURATION INTERFERENCE PREVENTION SYSTEM

When the boom is raised at a normal speed

The boom switches A, B, and C are turned on; the
offset switch R is turned off; the offset switch L is
turned on; and the solenoids 1, 2, and 3 are turned on.
The solenoid 1 connects the port A1 and port B1 of the
solenoid valve to supply the pilot pressure to the offset
section (6) of the control valve. The solenoids 2 and ÒONÓ SOL3

3 connect the ports A2 and B2 of the solenoid valve to A2

supply the pilot pressure to the boom section (5) of the A

R NC
control valve. Also, the left offset can be operated. C NO

Boom switch A ON Solenoid 1 ON ÒONÓ

B2
Boom switch B ON Solenoid 2 ON B ÒOFFÓ

Boom switch C ON Solenoid 3 ON ÒONÓ L ÒONÓ SOL2

C
Offset switch R OFF ÒONÓ A1
B1
ÒONÓ
Offset switch L ON
ÒONÓ SOL1

When the boom is further raised to the boom interfer- - +

ence detection position E, the boom switch B is turned R

off. This, however, will not change the operation of
the solenoid and the boom continues to be raised at a
normal speed until it reaches the bucket interference
detection position F. L

Boom switch A OFF Solenoid 1 ON L 5

R
6
Boom switch B OFF Solenoid 2 ON B L M H
1
Boom switch C ON Solenoid 3 ON 2
3 R
L
Offset switch R OFF J1C907

Offset switch L ON

When the boom raising is stopped

When the boom is raised to the bucket interference
detection position F, the boom switch C is turned off;
the solenoids 1, 2, and 3 are turned off; and the pilot
pressure to the boom section (5) is shut off to stop the ÒOFFÓ SOL3
A2
boom raising. At this time, the port B1 and the tank
A
port are connected to shut off the pilot pressure and R NC
the left offset cannot be operated. C NO

Boom switch A OFF Solenoid 1 OFF ÒOFFÓ

B2
Boom switch B OFF Solenoid 2 OFF B ÒOFFÓ

Boom switch C OFF Solenoid 3 OFF ÒOFFÓ L ÒOFFÓ SOL2

C
Offset switch R OFF ÒOFFÓ ÒONÓ
B1
A1
Offset switch L ON ÒOFFÓ SOL1

- +

B L M H
1 L
2
3
L 5
R
6

R
L
J1C905

TB53FR III-48
INTERFERENCE PREVENTION SYSTEM MACHINE CONFIGURATION
When the boom is in front of the cab and in
the left offset state
When the boom is raised while it is in front of the cab
and in the left offset state.

E
D

L2C910

When the boom is in normal operation

The boom switches A, B, and C are turned on; the
offset switches R and L are turned off; and the
solenoids 1, 2, and 3 are turned on.
The solenoid 1 connects the ports A1 and B1 of the
solenoid valve to supply the pilot pressure to the offset ÒONÓ SOL3

section (6) of the control valve. The solenoids 2 and A2

A
3 connect the ports A2 and B2 to supply the pilot R NC
pressure to the boom section (5) of the control valve. C NO

This permits the boom to be raised at a normal speed ÒONÓ

B2
to the boom deceleration detection position D.
B ÒOFFÓ

Boom switch A ON Solenoid 1 ON ÒONÓ L ÒONÓ SOL2

C
Boom switch B ON Solenoid 2 ON B1
ÒONÓ ÒOFFÓ A1
Boom switch C ON Solenoid 3 ON
ÒONÓ SOL1
Offset switch R OFF
Offset switch L OFF - +

B L M H
1 L
2
3
L 5
R
6

R
L
J1C911

III-49 TB53FR
MACHINE CONFIGURATION INTERFERENCE PREVENTION SYSTEM

When the boom raising is decelerated

When the boom is raised to the boom deceleration
detection position D, the boom switch A is turned off
and the solenoid 3 is turned off. The solenoids 2 and
3 connect the ports A2 and B2 of the solenoid valve,
but part of the oil flows into the tank, functioning as
the pressure reducing valve. This decelerates the ÒOFFÓ SOL3
A2
boom raising speed.
A
Boom switch A OFF Solenoid 1 ON R NC
C NO
Boom switch B ON Solenoid 2 ON
ÒOFFÓ
Boom switch C ON Solenoid 3 OFF B2

Offset switch R OFF B ÒOFFÓ

L ÒONÓ SOL2
Offset switch L OFF C
ÒONÓ

B1
ÒONÓ ÒOFFÓ A1

ÒONÓ SOL1

- +

B L M H
1 L
2
3
L 5
R
6

R
L
J1C912

When the boom raising is stopped

When the boom is raised up to the boom interference
detection position E, the boom switch B is turned off
and the solenoids 1, 2, and 3 are turned off. At this
time, the solenoid valve operates as the flow control
valve to relieve the shock when the boom stops. ÒOFFÓ SOL3
A2
Also, the port B1 and the tank port are connected to
A
shut off the pilot pressure, and the left offset cannot be R NC
operated. C NO

ÒOFFÓ
Boom switch A OFF Solenoid 1 OFF B2

Boom switch B OFF Solenoid 2 OFF B ÒOFFÓ

Boom switch C ON Solenoid 3 OFF ÒOFFÓ L ÒOFFÓ SOL2

C
Offset switch R OFF ÒONÓ ÒOFFÓ A1
B1

Offset switch L OFF ÒOFFÓ SOL1

- +

L 5
R
6
B L M H
1
2
3 R
L
J1C913

TB53FR III-50
INTERFERENCE PREVENTION SYSTEM MACHINE CONFIGURATION
Bucket switch
STD BUCKET position
Refer to pages III-46 to III-50 for the operation of the
interference detection device when the bucket switch
is set to STD BUCKET.

J1C914

LESS THAN 800 mm position F

E
When the bucket switch is at LESS THAN 800 mm, D
raising the boom in the right offset state (small swirl-
ing state) will cause the interference detection device
to function, preventing the boom from reaching its
highest position and ensuring no interference be-
tween the cab and the bucket.

J1C915

When the boom is in normal operation

The boom switches A, B, and C are turned on; the
offset switches R and L are turned on; and the sole-
noids 1, 2, and 3 are turned on.
The solenoid 1 connects the ports A1 and B1 of the
solenoid valve to supply the pilot pressure to the offset ÒONÓ SOL3

section (6) of the control valve. The solenoids 2 and A2

3 connect the ports A2 and B2 to supply the pilot A

R NC
pressure to the boom section (5) of the control valve. C NO

Boom switch A ON Solenoid 1 ON ÒONÓ

B2
Boom switch B ON Solenoid 2 ON B ÒONÓ

Boom switch C ON Solenoid 3 ON ÒONÓ L ÒONÓ SOL2

C
Offset switch R ON ÒONÓ ÒONÓ A1 B1

Offset switch L ON ÒONÓ SOL1

- +

L 5
R
6
B L M H
1
2
3 R
L
J1C916

III-51 TB53FR
MACHINE CONFIGURATION INTERFERENCE PREVENTION SYSTEM

When the boom reaches the boom deceleration detec-

tion position D the boom switch A is turned off, but
the solenoid valves continue to function and the boom
rises at normal speed.
Boom switch A OFF Solenoid 1 ON
Boom switch B ON Solenoid 2 ON
ÒONÓ SOL3
Boom switch C ON Solenoid 3 ON A2

Offset switch R ON A
R NC
Offset switch L ON C NO

ÒOFFÓ
B2
When the boom is further raised to the boom interfer- B ÒONÓ
ence detection position E the boom switch B is turned L ÒONÓ SOL2
ÒONÓ
off, but the solenoid valves continue to function and C
B1
the boom rises at normal speed. ÒONÓ ÒONÓ A1

Boom switch A OFF Solenoid 1 ON ÒONÓ SOL1

Boom switch B OFF Solenoid 2 ON - +

Boom switch C ON Solenoid 3 ON

R
Offset switch R ON
Offset switch L ON

L 5
R
6
B L M H
1
2
3 R
L
J1C917

When the boom raising is stopped

When the boom is raised to the boom interference
detection position E, the boom switch C is turned off;
the solenoids 1, 2, and 3 are turned off; and the pilot
pressure to the boom section (5) is shut off to stop the
boom raising. At this time, the port B1 and the tank “OFF” SOL3
A2
port are connected to shut off the pilot pressure and
A
the left offset cannot be operated. R NC
C NO
Boom switch A OFF Solenoid 1 OFF
“OFF”
Boom switch B OFF Solenoid 2 OFF B2

Boom switch C OFF Solenoid 3 OFF B “ON”

Offset switch R ON “OFF” L “OFF” SOL2

C
Offset switch L ON “OFF” “ON” A1
B1

“OFF” SOL1

- +

B L M H
1 L
2
3
L 5
R
6

R
L
J1C918

TB53FR III-52
INTERFERENCE PREVENTION SYSTEM MACHINE CONFIGURATION
MORE THAN 800 mm position
When the bucket switch is at MORE THAN 800 mm, E
D
raising the boom will cause the interference detection
device to function, regardless of whether the offset
switches L and R that detect the left and right offset
positions are on or off, preventing interference be-
tween the cab and the bucket.

J1C919

When the boom is in normal operation

The solenoid 1 connects the ports A1 and B1 of the
solenoid valve to supply the pilot pressure to the offset
section (6) of the control valve. The solenoids 2 and
3 connect the ports A2 and B2 to supply the pilot
pressure to the boom section (5) of the control valve. ÒONÓ SOL3
A2
This permits the boom to be raised at a normal speed
A
to the boom deceleration detection position D. R NC
C NO
Boom switch A ON Solenoid 1 ON
ÒONÓ
Boom switch B ON Solenoid 2 ON B2

Boom switch C ON Solenoid 3 ON B ÒONÓ

Offset switch R ON ÒONÓ L ÒONÓ SOL2

C
Offset switch L ON ÒONÓ ÒONÓ A1 B1

ÒONÓ SOL1

- +

L 5
R
6
B L M H
1
2
3 R
L
J1C920

III-53 TB53FR
MACHINE CONFIGURATION INTERFERENCE PREVENTION SYSTEM

When the boom raising is decelerated

When the boom is raised to the boom deceleration
detection position D, the boom switch A is turned off
and the solenoid 3 is turned off. The solenoids 2 and
3 connect the ports A2 and B2 of the solenoid valve,
but part of the oil flows into the tank, functioning as
the pressure reducing valve. This decelerates the ÒOFFÓ SOL3
A2
boom raising speed.
A
Boom switch A OFF Solenoid 1 ON R NC
C NO
Boom switch B ON Solenoid 2 ON
ÒOFFÓ
Boom switch C ON Solenoid 3 OFF B2

Offset switch R ON B ÒONÓ

ÒONÓ L ÒONÓ SOL2

Offset switch L ON C
A1 B1
ÒONÓ ÒONÓ

ÒONÓ SOL1

- +

B L M H
1 L
2
3
L 5
R
6

R
L
J1C921

When the boom raising is stopped

When the boom is raised up to the boom interference
detection position E, the boom switch B is turned off
and the solenoids 1, 2, and 3 are turned off. At this
time, the solenoid valve operates as the flow control
valve to relieve the shock when the boom stops. ÒOFFÓ SOL3
A2
Also, the port B1 and the tank port are connected to
A
shut off the pilot pressure, and the left offset cannot be R NC
operated. C NO

Boom switch A OFF Solenoid 1 OFF ÒOFFÓ

B2
Boom switch B OFF Solenoid 2 OFF B ÒONÓ

Boom switch C ON Solenoid 3 OFF ÒOFFÓ L ÒOFFÓ SOL2

C
Offset switch R ON ÒONÓ ÒONÓ
B1
A1
Offset switch L ON ÒOFFÓ SOL1

- +

B L M H
1 L
2
3
L 5
R
6

R
L
J1C922

TB53FR III-54
INTERFERENCE PREVENTION SYSTEM MACHINE CONFIGURATION
INSPECTION AND ADJUSTMENT

Inspection
Inspection when the boom is in the small slewing
state
• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Attachment interference switch: Standard
bucket.
• Fully extend the arm and bucket cylinders.

1. Confirm that the boom will be raised to the top

position at a normal speed when it is in the right
offset state where the bucket and the cab will
cause no interference.

2. Confirm that the offset will be stopped when the

left offset is operated upon the boom raise stop.

L2C903
Inspection when there is no interference be-
tween the bucket and the cab
• Engine : Rated r.p.m.
• Hydraulic Oil Temp. : 50~60°C
• Attachment interference switch: Standard
bucket.
• Fully extend the arm and bucket cylinders.

1. Raise the boom that is parallel to the body and in H

the right offset state where the bucket and the cab
will not interfere with each other. F

2. Confirm that the boom stops at the bucket inter-

ference detection position F.

3. Let the bucket tooth tip approach the cab and

confirm the clearance G.
• The clearance G cannot be adjusted. This value
is determined by the adjustment of the boom
raise stop position.

4. Lower and stop the boom. G

• This is the position where the boom switch (to
detect the bucket interference) is turned on.

5. Operate the left offset and confirm that the boom

will stop at the position (clearance H) where the
boom will not interfere with the cab.
J1C906
• H: 90~100 mm

III-55 TB53FR
MACHINE CONFIGURATION INTERFERENCE PREVENTION SYSTEM

Inspect the boom raise stop position

• Engine : Rated r.p.m. D E
• Hydraulic Oil Temp. : 50~60°C
• Bucket changeover switch: Standard bucket.
• Fully extend the arm and bucket cylinders.
1
1. Confirm that the boom is in front of the cab and
the side of the bucket is parallel to the cab.

2. Raise the boom and confirm that it decelerates at

the boom deceleration detecing position D by the J
pressure reducing valve, and stops at the boom
interference detection position E with the shock
relieved by the operation of the flow control F4C916

valve.

3. Measure the height J from the ground to the arm

point pin (1).
• J: 2350 mm
• Adjust if not in accordance with these values.
If the interference prevention device is faulty
and the boom cannot be stopped, the swing
bracket’s link mechanism enables the stopper
pin to move to the boom stopper position,
stopping the boom.

Adjustment
A B C
Adjusting the boom raise stop position
1. Remove the installation bolts and the cover. 1

2. Adjust the boom switches A, B, and C.

• Adjustments in setting the boom switches A,
B, and C should be done at the position where
the cam roller (3) is on the cam plate (2), and
the switch is shortened by a stroke of 4 mm
from the free state position (with a stroke of 2
mm, the switch is turned on) and set.
2
3. Loosen the installation bolt on the switch box (1) L2C915

to adjust its mounting position so that the height

J becomes equal to the set value when the boom
stops.
C
For the inspection of the height J, see the former
B
section “Inspect the boom raise stop position.”
A
3

1
2

L2C916

TB53FR III-56
INTERFERENCE PREVENTION SYSTEM MACHINE CONFIGURATION
• A .... side raises the height.
B ..... side lowers the height. 1
If the correct height J cannot be obtained by
adjusting the switch box position, adjust the
cam plate (2).
• Slow down the engine’s rotational speed and A B
2
confirm that the height J is within the specified
range. Confirm the height J again at the engine’s
rated rotational speed. B
Never try to adjust the boom raise stop position
using the switch setting adjustment. Otherwise,
the adjusted position may deviate and cause A
interference between the boom and the cab.
J1C923

Adjusting of the boom left offset stop position

1. Remove the installation bolts and the cover.

2. Adjust the offset switches R and L.

• The offset switches R and L should be adjusted
at the position where the cam roller (3) is on the
angle (1) and the switch stroke is shortened by
4 mm from the free position and set.

3. Adjust the angle (1) and confirm that the clear-

ance H between the boom and the cab in the left
offset state is within the specified range.
For the inspection of the clearance H, see the R L
section “Inspection when there is no interference
between the bucket and the cab.”
• The clearance H should be adjusted by shifting J1C924

the angle (1) upward or downward.

Moving the angle (1) upward narrows the
clearance H.
Moving the angle (1) downward widens the
clearance H.
• Slow down the engine’s rotational speed and
confirm the clearance H is within the specified 2
range.
Confirm the clearance H again at the engine’s
rated rotational speed. 3
• After adjustment, if the clearance H is still less
than 90 to 100 mm, place a shim (4) such as a
4
washer between the angle (1) and the link arm
(2). 1 F4C918

III-57 TB53FR
MACHINE CONFIGURATION INTERFERENCE PREVENTION SYSTEM

TB53FR III-58
IV . HYDRAULIC UNITS

III-59
IV-1 TB53FR
HYDRAULIC UNITS

CONTENTS

Hydraulic Pump ..................................................................................................................................................... 3

Control Valve ...................................................................................................................................................... 35
Solenoid Valve .................................................................................................................................................... 57
Pilot Valve ........................................................................................................................................................... 65
Pilot Valve (Offset) ............................................................................................................................................. 73
Cylinders .............................................................................................................................................................. 77
Travel Motor ........................................................................................................................................................ 95
Slew Motor ........................................................................................................................................................ 119
Swivel Joint ....................................................................................................................................................... 151

TB53FR III-60
IV-2
HYDRAULIC PUMP HYDRAULIC UNITS
HYDRAULIC PUMP
CONSTRUCTION

11

1 2 5 8
9 10

3 6 4 7

K3D100

1. Shaft 7. Gear Pump

2. Swash Plate 8. Housing
3. Cylinder Block 9. Solenoid Valve
4. Cover 10. Relief Valve
5. Control Spring 11. Valve
6. Control Piston

IV-3 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

Shaft
5 7 6 4 3 8

1. Shaft
2. Seal Case
3. Bearing
4. Snap Ring
5. Oil Seal
1 2 6. O-ring
K3D101 7. Snap Ring
8. Snap Ring

Swash Plate

1. Swash Plate
2. Plate
3. Distance Piece
4 3 5 2 1 4. Bearing
K3D102
5. O-ring

Cylinder Block
1 7 2 6

4 1. Piston
2. Cylinder Block
3. Retainer
5 4. Plate
5. Guide
9 6. Spring
3 7. Pin
8. Spring Seat
K3D103
9. Snap Ring

TB53FR IV-4
HYDRAULIC PUMP HYDRAULIC UNITS
Cover
3 7

1. Cover
2. Valve Plate
3. Pin
4 6 9 5 10 2 11 1 5 4. Plug
4 8.9
5. Orifice
6 6. Plug
7. Bearing
8. Plug
9. O-ring
6 5 8.9 K3D104 10. O-ring
11. O-ring

Control Spring
1 4 7 9 2 5 8 6 3

1. Spring Seat
2. Spring Seat
3. Cover
4. Spring
5. O-ring
K3D105 6. Adjusting Screw
7. Spring
8. Nut
9. Shim

Control Piston
2 5 3 1

7 6 1. Cylinder
2. Piston
3. Pin
4. Pin
8 9 3 4 5. O-ring
J1D106 6. Conical Spring Washer
7. Spring Seat
8. O-ring
9. O-ring

IV-5 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

Gear Pump (P3)

9 10 14 4 3 7 13 1 17 16

18 2 15 6 5 6 15 11 8 12 12

K3D107

1. Gear Pump 7. Plate 13. Seal Ring

2. Flange 8. Guide 14. Angular Ring
3. Case 9. Coupling 15. Pin
4. Drive Gear 10. Bushing 16. O-ring
5. Driven Gear 11. O-ring 17 O-ring
6. Bushing 12. O-ring 18. O-ring

Gear Pump (P4)

10 11 1 8 3 2

1. Frame
2. Housing
7 9 3. Drive Gear
4. Driven Gear
5. Plate
6. Metal
7. Backup Ring
8. Pin
9. Seal Ring
10. Coupling
12 5 4 6 11. Snap Ring
K3D108
12. O-ring

TB53FR IV-6
HYDRAULIC PUMP HYDRAULIC UNITS
Solenoid Valve
Y

X X

Y
8 7
1. Body
2. Spool
3
3
3. O-ring
2 4. O-ring
4 6 4 5. Spring
1 2 6. Filter Element
5 X-X Y-Y
K3D109
7. Solenoid A
8. Solenoid B

Relief Valve
2

5
6

1. Spool
1
2. Screw
3. O-ring
4. Spring
5. Nut
K3D110
6. Shim

IV-7 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

OPERATION

Piston Pump
This pump is a variable displacement piston pump
with a single cylinder block, which discharges two
equal volumes.
Ten pistons (2) are installed in the cylinder block (1),
and the end surface is in contact with the valve plate
(3). The suction port C and the discharge port A of the
pump P1 and the discharge port B of the pump P2 are
arranged in the valve plate (3). On the other hand, the
swash plate (4) is fastened to the housing at a given
inclination, and the pistons (2) rotate along this swash
plate (4).
When the shaft (5) is rotated, the cylinder block (1)
rotates, the pistons (2) in the cylinder block execute 2 4
reciprocating movement along the swash plate (4),
and the pump executes suction and discharge. At this 1
3
time, the pistons in contact with the discharge port A
of the valve plate (3) operate as the pump P1, while the C
pistons in contact with the discharge port B operate as
the pump P2.
In this way, the ten pistons (2) execute one suction and SUCTION
discharge stroke with each revolution of the cylinder SUCTION STROKE
block (1), so that suction and discharge are executed
continuously when the shaft (5) is rotated continu- P1 A
P2 B DISCHAGE STROKE
ously. DISCHARGE
As the piston stroke displacement depends on the K3D111

inclination of the swash plate (4), the discharge flow

quantity can be changed by changing the inclination
of the awash plate (4).

Discharge volume control

The swash plate (4) is equipped with the bearings (6)
and is mounted on the housing at an inclination that
can be varied. The swash plate (4) is loaded with the
pistons (9) and the piston (10) in opposition to the
spring (7). The discharge pressures from the pumps
P1 and P2 work on the pistons (9). The discharge
pressure from the pump P3 works on the piston (10).
When the discharge pressure is below the value preset
for the spring (7), the inclination of the swash plate (4)
is fixed to the maximum value by the spring (7).

TB53FR IV-8
HYDRAULIC PUMP HYDRAULIC UNITS
When the discharge pressure exceeds the set value of
the spring (7), the swash plate (4) is pushed by the

TOTAL PRESSURE ∑P
pistons (9) and (10), the inclination decreases, and the 10 P2
swash plate is kept at an inclination where the dis-
charge pressure and the spring force are balanced. A+B
When the pressure acting onto the pistons (9) and (10) A
increases still further, the inclination of the swash
plate (4) becomes still smaller. The until now inactive
spring (8) also becomes active, and a still higher
9 P1
discharge pressure will be required to counteract this ∑Pi SET HORSEPOWER P3
spring force. CURVE
In this way, the inclination of the swash plate (4) is Qmax
changed, the discharge quantity is controlled, the FLOW VOLUME Q
K3D112
pump is supplied only with the pressure and the flow
volume required for the load, and the pump loss
pressure is reduced.
As the inclination of the swash plate (4) changes not
only according to the operation pressure of the pumps
P1 and P2, but also according to the operation pres-
sure of the pump P3, the P-Q curve of the piston pump
becomes a curve with effective use of the engine
power (full power control).

Gear Pump
The gear pump consists of a single gear case, inside of
which is a drive gear (1) and a driven gear (2) engaged
with each other. By turning the drive shaft (3), the
space between the case and the gears is filled with oil.
This oil is thus sent through the pump from the inlet
to the outlet.
INLET OUTLET

Pilot Relief Valve and Solenoid Valve 1 A

The pilot relief valve (1) keeps the pressure in the pilot PA
circuit constant by releasing the oil into the tank PB
passage when the discharged oil pressure from the P
pump P4 (2) exceeds the preset value. 2
B
This pilot pressure is switched by the solenoid valve
A (that switches the second travel speed) and the
solenoid valve B (that switches the lever lock).

G4D103

IV-9 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

Solenoid Valve
When Current is NOT Flowing
Oil at port P is blocked by the spool (1). Also, since
port A and port T are connected, the pressure in the
pilot circuit downstream becomes the same as the
tank pressure. T

P A

G4D109

When Current is Flowing

A magnetic field is generated around the coil and the
plunger (2) is pulled down. This pushes the spool (1)
down. As a result, oil at port P flows into port A and
pressure is transmitted to the pilot circuit at the 2
bottom.

P A

G4D108

TB53FR IV-10
HYDRAULIC PUMP HYDRAULIC UNITS
DISASSEMBLY AND ASSEMBLY

Table of Special Tools

Unit: mm
NAME, DIMENSIONS NAME, DIMENSIONS
JIG (A) JIG (B)

1 2

General Cautions
• Carry out disassembly and assembly operations in • Replace all seals with new ones each time the pump
a clean place and provide clean containers to place is disassembled, coating them lightly with grease.
the disassembled parts in. • Check each part to make sure there is no abnormal
• Before disassembly, clean around the ports and wear or seizing and use sandpaper, etc. to remove
remove the paint from each joint using a wire any burrs, sharp edges, etc.
brush. • Adjust adjustment screws only when required.
• Clean each of the disassembled parts with a clean-
ing oil such as diesel fuel.
• Make match marks on each part so that they will be
assembled in the same positions when assembled.

Disassembly
1. Take out the cap screws and remove the solenoid
valve from the pump.
Place the pump with the shaft facing down onto
the jig (A) so that the shaft end is not in contact
with anything.

K3D117

2. Remove the cap screws and remove the gear

pump.

K3D118

IV-11 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

3. Remove the coupling.

K3D119

4. Remove the cap screws and remove the cover.

• Remove the cover in horizontal condition.
• Use care, as the valve plate is installed on the
rear.
• When the cover is difficult to remove, tap it
with a plastic hammer.

5. Remove the two springs [inside, outside].

6. Remove the spring seat (1).

7. Disassemble the cylinder block.

a. Remove the cylinder block from the shaft.

TB53FR IV-12
HYDRAULIC PUMP HYDRAULIC UNITS
b. Remove the plate from the shaft.

c. Remove the guide (3), the pin (4), the retainer 5 3 4

(5), and the piston (6) from the cylinder block
(7).
• Disassemble the inside of the cylinder block
(7) only when required.

6 7
E5D101

8. Remove the snap ring and remove the oil seal case
(8) and the O-ring.
• Use two flat screwdrivers as shown in the
figure to remove the oil seal case.

9. Remove the shaft while tapping its rear end with

a plastic hammer.

IV-13 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

10. Disassemble the swash plate part.

a. Remove the cap screws and remove the plate
(9).
b. Remove the distance piece (10).
c. Remove the bearing (11).

11
10
9
K3D121

d. Remove the swash plate.

11. Disassemble the cover part.

a. Remove the valve plate.

b. Remove the cap screws and remove the control

piston part.
• Disassemble the control piston part only 14
when required.

K3D122

TB53FR IV-14
HYDRAULIC PUMP HYDRAULIC UNITS
c. Remove the pins (12), piston (13) from the
cylinder (14). 13
12
d. Remove the piston (15) for the air-conditioner
(if equipped). 14

16 15
K3D123

e. Remove the piston (16).

16

K3D124

f. Remove the three conical spring washers and

the spring seat.

K3D125

g. Remove the cap screws and remove the cover.

IV-15 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

h. Remove the spring seat, and remove the O-ring

from the spring seat.

12. Disassemble the shaft part.

a. Remove the snap ring.
b. Remove the shaft while tapping it with a plas-
tic hammer.

13. Remove the relief valve.

• The parts inside the relief valve should not be
disassembled unless absolutely necessary.
a. Remove the nut.
• Record the length of the adjusting screw
protrusion before starting the disassembly.

K3D126

b. Remove the adjusting screw (17).

• Be careful not to miss the shim.
c. Remove the spring (18).
d. Remove the spool (19).

19
18
17

K3D127

TB53FR IV-16
HYDRAULIC PUMP HYDRAULIC UNITS
14. Remove the cap screws to disassemble the hy-
draulic pump into the pump P3 and the pump P4.

K3D128

15. Disassemble the pump P4.

a. Remove the plate, backup ring and seal ring
while pulling the drive gear.

K3D129

b. Remove the driven gear.

K3D130

16. Disassemble the pump P3.

a. Remove the bolts and then the flange.

K3D131

IV-17 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

b. Remove the frame.

K3D132

c. Remove the seal ring.

d. Remove the plate, guide and O-ring.

K3D133

e. Remove the plate.

K3D134

TB53FR IV-18
HYDRAULIC PUMP HYDRAULIC UNITS
f. Remove the drive gear, driven gear and bush-
ing.

K3D135

17. Disassemble the solenoid valve.

a. Remove the cap screws and then the solenoids.
• Be careful not to miss the push rod in the
solenoid valve.

K3D136

b. Remove the spool and spring.

c. Remove the O-ring.

K3D137

IV-19 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

Assembly
1. Assemble the swash plate part.
a. Install the swash plate in the housing.

b. Install the bearing (11).

c. Install the distance piece (10).
• Bearing pre-load: 0.08~0.12 mm
d. Install the O-ring in the plate (9).
e. Attach the plate (9) and fix it with the cap
screws.
Cap screw: 12~15 N·m

11
10
9
K3D121

2. Assemble the shaft part.

a. Use the jig (B) to install the bearing on the
shaft.
• Use the bearing as the base, and use a press
or a plastic hammer.
b. Install the snap ring to fix the bearing.

3. Install the shaft in the housing.

• Tap the spline end with a plastic hammer to
positively install the outer race of the bearing
in the housing hole.

4. Install the O-ring.

TB53FR IV-20
HYDRAULIC PUMP HYDRAULIC UNITS
5. Install the oil seal case with installed oil seal.
• Install the oil seal case so that it is straight.

6. Install the snap ring.

7. Assemble the cylinder block.

a. Install the pin (4) in the cylinder block.
• Apply grease to the pin (4) to prevent its
dropping off.

b. Install the guide (3) in the cylinder block.

• Apply grease to the spherical part of the
guide.
c. Attach the piston (6) to the retainer (5), and
install the retainer (5) in the cylinder block.

8. Install the plate on the swash plate.

• In order to prevent dropping off, apply grease
at the rear (A) of the plate on the swash plate
side.

A K3D138

IV-21 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

9. Install the cylinder block matching the spline of

the shaft.
• Apply grease to the sliding surfaces of the
piston shoes and the plate.

10. Install the spring seat (1).

• Apply grease to the spherical part of the spring
seat.

11. Install the two springs [inside, outside].

12. Assemble the cover unit.

a. Install the spring seat (18), the three conical
spring washers (17).
• Be careful of the installation direction of the
washers.
16
17
18

K3D139

K3D125

b. Install the piston (16).

16

K3D124

TB53FR IV-22
HYDRAULIC PUMP HYDRAULIC UNITS
c. Install the piston (15) for the air-conditioner (if
equipped). 13
12
d. Fit the O-rings to the cylinder (14).
e. Apply grease to the two pins (12), the piston 14
(13) and install them in the cylinder (14).

16 15
K3D123

f. Put the cylinder (14) in position and install the

cap screws.
Cap screw: 28~35 N·m 14
• Apply Loctite #270.

K3D122

g. Fit the O-ring to the spring seat and install the

spring seat.

h. Put the cover in place and install the cap

screws.
Cap screw: 28~35 N·m

IV-23 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

i. Apply grease to the rear of the valve plate and

install it to the cover, matching the knock hole.
j. Install a large and a small O-ring in the cover.

13. Install the relief valve.

a. Install the spool (19).
b. Install the spring (18).
c. Fit the shim to the adjusting screw (17) and
install it in the cover.

19
18
17

K3D127

d. Install the nut.

K3D126

14. Install the cover and install the cap screws.

• Install the cover parallel to the housing instal-
lation surface.
Cap screw: 98~123 N·m

TB53FR IV-24
HYDRAULIC PUMP HYDRAULIC UNITS
15. Fit the O-rings to the cover.

K3D140

16. Install the coupling on the end of the main pump

shaft.

K3D119

17. Assemble the gear pump.

a. Match the bushing and install the rectangular
ring (20).
• Pay attention to the installation direction.
20

A B A
K3D141
A: DISCHARGE SIDE
B: SUCTION SIDE

b. Install the bushings assembled as described

above on both sides of the drive gear and the
driven gear, and install them in the housing.

K3D135

IV-25 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

c. Fit the O-ring to the guide (18) and mount them

on the plate (17).
• The O-ring on the guide should come to the
largely-rounded side of the plate circumfer-
ence.

18

17 K3D143

K3D142

d. Install the plate assembled as described above

in the housing.

K3D133

e. Install two plates in the housing.

• Be careful of the installation directions of
the plates.
A: DISCHARGE SIDE
B: SUCTION SIDE

B A

K3D144 K3D134

f. Mount the seal ring.

TB53FR IV-26
HYDRAULIC PUMP HYDRAULIC UNITS
g. Fit two parallel pins to the frame and mount
them on the pump.

K3D145

18. Assemble the pump P4.

a. Install the drive gear in the housing.

K3D146

b. Install the driven gear in the housing.

K3D147

c. Fit the seal ring and backup ring to the plate.

• Apply grease to the rings in advance to
prevent them from dropping off.

K3D148

IV-27 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

d. Install the plate in the housing.

K3D149

e. Fit the pins and O-ring to the frame.

K3D150

f. Install the frame in the housing.

K3D132

g. Fix the frame and the housing with the cap

screws.
Cap screw: 29 N·m

K3D151

TB53FR IV-28
HYDRAULIC PUMP HYDRAULIC UNITS
h. Fit two pins to the frame and mount the cou-
pling on the shaft end on the side of the pump
P3.

K3D152

19. Unite the pump P3 and the pump P4 and fix them
with the bolt.
Bolt: 59 N·m

K3D153

20. Fit the O-ring to the frame.

K3D154

21. Assemble the solenoid valve.

a. Mount the spring and spool on the body.

K3D137

IV-29 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

b. Mount the O-ring on the body.

K3D155

c. Mount the solenoids on the body and fix them

with the cap screws.
Cap screw: 3.4~4.4 N·m

K3D136

d. Fit the O-ring to the body.

K3D156

22. Unite the main pump and gear pump and fix them
with the cap screws.
Cap screw: 55~69 N·m

K3D118

TB53FR IV-30
HYDRAULIC PUMP HYDRAULIC UNITS
23. Mount the solenoid valve on the pump and fix it
with the cap screws.
Cap screw: 28~35 N·m

K3D117

IV-31 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

INSPECTION AND ADJUSTMENT

Checking the Parts

Parts Judgment Criteria Treatment

Piston and cylinder • A clearance S of 0.05 mm or more • Exchange
block assembly between the piston and the cylinder
block
• Occurrence of scratches, scoring, • Exchange.
abnormal wear, etc. on sliding parts

Slack of the piston • A slack S of 0.2 mm or more for the • Exchange

shoe piston shoe

Shaft and oil seal OIL SEAL MOUNT • A wear amount of 0.025 mm at the • Exchange
installation part installation part of shaft and oil seal

STANDARD DIMENSION

Valve plate • No abnormal scratches (0.02 mm or • Correct by lapping

more), wear, or sticking for the slid- or exchange.
ing surfaces
Bushing • No abnormal wear or harmful • Exchange
scratches of the sliding surfaces
Seals and O-rings • At the time of reassembly after dis- • Exchange
assembly
Drive gear and • No abnormal scratches, wear, or • Exchange
driven gear flaking of the tooth surfaces
Ball bearings and • No abnormal scratches, wear, or • Exchange the shaft
needle bearings flaking of the rolling surfaces and the assembly.

TB53FR IV-32
HYDRAULIC PUMP HYDRAULIC UNITS
TROUBLESHOOTING

Symptom Probable Causes Remedy

Noise is loud. Abnormal • The suction hose is pinched or the suc- • Remove the dirt or eliminate the pinched
noise is generated. tion filter is clogged. condition of the hose.
• The suction side joint is loose and air is • Retighten each joint.
being sucked in.
• The hydraulic oil’s viscosity is too high • Replace the hydraulic oil with oil of the
and cavitation is occurring. proper viscosity.
• The pump is off center with respect to • Center the pump with respect to the
the engine. engine.
• There are bubbles in the hydraulic oil. • Investigate the cause of the bubbles and
repair it.
• The engine’s speed is higher than the • Operate the engine at the specified speed.
specified speed.
• The drain back pressure is higher than • Check and replace the drain piping.
the specified pressure.
• The bearing, etc. is mechanically dam- • Replace the damaged parts or replace
aged. the pump.
Discharge is insufficient. • The engine’s speed is too low. • Operate the engine at the specified speed.
• The oil temperature is abnormally high. • Stop the machine and let the oil cool off,
then check again.
• The hydraulic oil’s viscosity is too high. • Replace the hydraulic oil with oil of the
proper viscosity.
• The pump’s volumetric efficiency has • Replace the pump.
dropped.
• The horsepower setting adjustment • Reset the screw and lock it.
screw is loose.
• The oil level in the tank is low. • Replenish the tank with hydraulic oil to
the specified level.
• The suction side pipe or the suction • Clean the piping.
filter is clogged.
• The amount of leakage from hydraulic • Repair the hydraulic device or replace
devices other than the pump is increasing. it.
Pressure doesn’t rise. • The relief valve setting has dropped. • Reset the relief valve setting.
• The amount of leakage from hydraulic • Repair the hydraulic device or replace
devices other than the pump is increasing. it.
• The pump’s volumetric efficiency has
dropped. • Replace the pump.
The rotational speed drops • The peak pressure is generated due to a • Repair the relief valve or replace it.
when there is a dynamic drop in the relief valve’s response.
load. • There is foreign matter trapped in the • Remove the foreign matter and repair or
pilot line or foreign matter is caught in replace the scratched parts.
the sliding parts of the control equip-
ment.
Abnormal heat is gener- • Leakage from the pump is increasing. • Replace the pump.
ated. • The bearings, etc. are mechanically dam- • Replace the damaged parts or replace
aged. the pump.
• There is seizing of sliding parts. • Replace the damaged parts or replace
the pump.
Hydraulic oil is leaking. • Seals are damaged. • Replace the seals.
• The shaft surface which slides against • Replace the shaft or replace the pump.
the oil seal is worn.
• The plug or bolts are loose. • Tighten them or replace the seals.

IV-33 TB53FR
HYDRAULIC UNITS HYDRAULIC PUMP

TB53FR IV-34
CONTROL VALVE HYDRAULIC UNITS
CONTROL VALVE
CONSTRUCTION

1 13 14 13 7 4 17 16 13 9

19
18

20 10 11 21 8 13 5 15 12 17 6 13 2 3

J1D200

1. Inlet Housing 12. Inlet Housing

2. Boom Block Assembly 13. Port Relief Valve
3. Bucket Block Assembly 14. Plug Assembly
4. Left Travel Block Assembly 15. Anti Cavitation Valve
5. Auxiliary Block Assembly 16. Port Relief Valve
6. Right Travel Block Assembly 17. Main Relief Valve
7. Swing Block Assembly 18. Tie Rod
8. Arm Block Assembly 19. Nut
9. Outlet Housing 20. Main Relief Valve
10. Dozer Blade Block Assembly 21. Switch Valve
11. Slew Block Assembly

IV-35 TB53FR
HYDRAULIC UNITS CONTROL VALVE

Left Travel Block

8 9

1. Screw
2. Spring Holder
3. Spring
3 4. Cover
2 5. Seal Holder
4 6. Backup Ring
1 7. O-ring
8. Poppet
7 6 5
K3D201 9. Spring

Right Travel Block

9 8

1. Screw
2. Spring Holder
3. Spring
1 4. Cover
4 5. Seal Holder
2
6. Backup Ring
7. O-ring
3
8. Poppet
5 6 7 K3D202 9. Spring

Swing Block

6 7

1. Cover
2. Screw
5 8 4 3. Spring Holder
4. Spring
5. Cover
6. Poppet
7. Spring
8. O-ring
8 9 3 2 1
J1D201 9. Spring Holder

TB53FR IV-36
CONTROL VALVE HYDRAULIC UNITS
Boom Block

6 7

1. Cover
2. Screw
4 9 8
3. Spring Holder
4. Spring
5. Cover
6. Poppet
7. Spring
1 2 3 8 5 8. O-ring
K3D204
9. Spring Holder

Slew Block

6 7

1. Cover
4 9 8 2. Screw
3. Spring Holder
4. Spring
5. Cover
6. Poppet
7. Spring
1 2 3 8 5 8. O-ring
K3D205
9. Spring Holder

Arm Block
10

9 7 6 1. Cover
2. Screw
3. Spring Holder
5 8 4. Spring
4 5. Cover
6. Poppet
7. Spring
8. O-ring
9. Poppet
3 2 1
10. Poppet
8 11
K3D206 11. Spring Holder

IV-37 TB53FR
HYDRAULIC UNITS CONTROL VALVE

Bucket Block

6 7 10
1. Cover
2. Screw
3. Spring Holder
4 9 8
4. Spring
5. Cover
6. Poppet
7. Spring
8. O-ring
1 2 3 8 5 9. Spring Holder
K3D207
10. Poppet

Dozer Blade Block

6 7

1. Cover
2. Screw
2 3. Spring Holder
4. Spring
1
5. Seal Holder
3
6. Poppet
4 7. Spring
5 9 8 8. O-ring
K3D208
9. Backup Ring

Switch Valve

1. Cover
4 6 8 2. Screw
3. Spring Holder
4. Spring
5. Cover
6. Spring Holder
7. O-ring
1 2 3 7 5
K3D209 8. O-ring

TB53FR IV-38
CONTROL VALVE HYDRAULIC UNITS
Auxiliary Block

6 7

1. Cover
2. Screw
5 8 4 3. Spring Holder
4. Spring
5. Cover
6. Poppet
7. Spring
8 9 3 2 1 8. O-ring
K3D210 9. Spring Holder

Main Relief Valve

1. Housing 10. Spring

2. Plug 11. Spring
3. Sleeve 12. O-ring
4. Main Poppet 13. Backup Ring
5. Piston 14. O-ring
6. Needle Valve 15. O-ring
7. Set Screw 16. O-ring
8. Washer 17. Washer
9. Lock Nut

Port Relief Valve

1. Housing 11. Lock Nut

2. Plug 12. O-ring
3. Sleeve 13. Backup Ring
4. Main Poppet 14. O-ring
5. Piston 15. Backup Ring
6. Needle Valve 16. O-ring
7. Spring 17. O-ring
8. Spring 18. Wave Washer
9. Set Screw 19. O-ring
10. Washer

IV-39 TB53FR
HYDRAULIC UNITS CONTROL VALVE

Anti-Cavitation Valve
2 11 1 12 7 8 1. Housing 8. Backup Ring
2. Plug 9. O-ring
3. Poppet 10. Backup Ring
4. Poppet 11. O-ring
4
5. Piston 12. O-ring
6. Spring 13. Wave Washer
5 7. O-ring

13 10 9 6 3
K3D211

TB53FR IV-40
CONTROL VALVE HYDRAULIC UNITS
OPERATION

When the Spool is in the Neutral Position

When the control valve spool is not moving, hydrau-
lic oil flows through the center bypass passage (1) and
then through the tank passage (T) in the arrow direc-
tion, returning to the tank.

When the Spool is Actuated

Explanation is given for the case where the spool is
moved to the right.
When the spool (2) is moved to the right, the center
bypass passage (3) is closed and hydraulic oil entering
from the pump passes through the load check valve
(5) from the parallel passage (4), flowing from the A
port to the actuator. On the other hand, oil returning
from the B port flows through the tank circuit (T) and
returns to the tank.

Load Check Valve

A load check valve (5) is included in each section
except the travel (right, left) sections.
This valve prevents oil from flowing backward due to
the load pressure (C) from the actuator port during
switching of the spool.

IV-41 TB53FR
HYDRAULIC UNITS CONTROL VALVE

Main Relief Valve

A main relief valve is mounted between the pump
circuit and tank circuit of each inlet housing and
serves to maintain the circuit pressure at the set value.

When the Relief Valve is NOT Operating

When the pressure in the circuit is low with respect to
the set value, the relief valve maintains equilibrium.
Hydraulic oil from the pump passes through the
orifice from chamber (C) and arrives at the spring
chamber (D) and the needle valve (1). On the other
hand, forces F and F1 are acting in the respective
arrow directions on both sides of the main poppet (2).
F = P × A Fl = P × A1
P: Pressure A, A1: Cross Sectional Area
Since the cross sectional area of A is less than that of
A1, the main poppet (2) is pushed by the force
“F1-F” to the seat surface on the left side.

When the Relief Valve is Operating

If the circuit's pressure becomes greater than the set
value of the spring (3), the needle valve (1) is pushed
to the right by hydraulic pressure and oil flows to the
tank passage (T). When this happens, a pressure
differential is generated between the two ends of
orifice of the main poppet (2), and this hydraulic
pressure pushes the main poppet toward the right. As
a result, the pressurized oil in the circuit flows to the
tank passage.
This operation maintains the pressure in the circuit at
the set value.

TB53FR IV-42
CONTROL VALVE HYDRAULIC UNITS
Port Relief Valve
Relieving Operation
When the pressure in the circuit is low with respect to
the set value, the relief valve is maintained at equilib-
rium. Pressure from the pump passes from chamber B
to the orifice in piston (4), then reaches chamber C and
the needle valve (5). On the other hand, forces F and
F1 are acting in the arrow directions on both sides of
the main poppet (6).
F = P × A F1 = P × A1
P: Pressure A, A1: Sectional Area
Since the sectional area of A is less than that of A1, the
main poppet (6) is pushed by the force “F1-F” to the
seat surface on the left side.

If the pressure in the circuit becomes higher than the

force of the spring (7), the needle valve (5) is pushed
to the right by hydraulic pressure, opening. Oil then
flows around the circumference of the needle valve
(5) and passes through the slits, flowing into the tank
passage (T).

When the needle valve (5) opens, the pressure drops

on the back side of the piston (4), pushing the piston
(4) to be pushed to the right, seating with the needle
valve (5). This shuts off the flow of hydraulic oil to the
rear of the main poppet (6). As a result, the pressure
in chamber C on the inside drops.

Compared to the chamber B side, the pressure in

chamber C is low and there is no equilibrium in
pressure. For this reason, the main poppet (6) opens
and pressurized oil flows to the tank passage (T).

IV-43 TB53FR
HYDRAULIC UNITS CONTROL VALVE

Suction Operation
When the cylinder is operated at high speed, and the
supply of oil cannot keep up with it, creating a vacuum
in chamber B, oil is supplied from the tank side,
preventing the occurrence of cavitation.
When the pressure in chamber B is lower than the
pressure in the tank passage (T), the differences in the
sectional areas A and A1 cause the main poppet (6) to
open. Thus, sufficient oil from the tank passage (T)
enters chamber B, filling the empty space.

Anti-Cavitation Valve P
The anti-cavitation valves are incorporated between
the cylinder ports of the swing and bucket sections
and the tank circuit. When a cylinder is operated at
high speed and when the supply of hydraulic oil can't
keep up with it, causing a vacuum to form at the
cylinder port, this valve supplies oil from the tank,
preventing cavitation from occurring. Normally in
the cylinder port, pressure is brought to bear, so the
poppet (1) is closed. If a vacuum is generated at the T
cylinder port (P) and the pressure in the tank passage 1
K3D212
(T) drops as a result, it pushes on the poppet (1) and
oil flows from the tank passage to the cylinder port.

TB53FR IV-44
CONTROL VALVE HYDRAULIC UNITS
Switch Valve
The switch valve is actuated only when the travel P3 P4
motor and hoe attachment are operated simultaneously. 4
3
When the Switch Valve is Actuated 5
When the spool of the hoe attachment is switched to
block the pilot passage (1) connected to the tank 2
passage, the pressure in the pilot chamber (2) is
preserved.
This switches the spool (3) to let the oil from the pump
P3 flow into the passages (4) and (5) through the notch
provided on the spool (3). As the passage (4) is
connected to the boom and bucket block while the
passage (5) is connected to the auxiliary block and
swing block, the hoe attachment can be operated
(except for arm operations) while the machine is
traveling. P2

P1

K3D213

When the Switch Valve is NOT Actuated P3 P4

The pilot passage (1) is opened to the tank passage, 3
making the pressure in the pilot chamber (2) equal to 6
2
that in the tank, and the spool (3) is not switched.
Therefore, the oil that has flowed into the switch valve
from the pump P3 returns to the tank from the passage
(6) through the center bypass passage of the arm
block.

P2

P1

K3D214

IV-45 TB53FR
HYDRAULIC UNITS CONTROL VALVE

Arm Conflux Circuit

When Moving the Arm In
When the pilot port (1) is pressurized and the spool (2) 5
3
is switched, the hydraulic oil from the pump P2
pushes up the load check valve (3) and flows into the
cylinder port (4). The hydraulic oil from the pump P3 P2 P3
4
joins the oil from the pump P2 through the poppet (5), 6
pushing up the load check valve (3) to let the oil flow
into the cylinder port (4). The resulting oil flow equals 2 1
the total oil flow from the pump P2 and pump P3.
The returning oil from the cylinder port (6) flows into
the tank passage and returns to the tank.

K3D215

When Moving the Arm Out 4

When the pilot port (7) is pressurized and the spool (2) 6
is switched, the hydraulic oil from the pump P2
pushes up the load check valve (3) and flows into the 7
cylinder port (6). The hydraulic oil from the pump P3
joins the oil from the pump P2 through the poppet (5),
pushing up the load check valve (3) to let the oil flow
into the cylinder port (6). The resulting oil flow equals
the total oil flow from the pump P2 and pump P3.
3 5
The returning oil from the cylinder port (4) flows into 2
the tank passage and returns to the tank.

P2 P3 K3D216

TB53FR IV-46
CONTROL VALVE HYDRAULIC UNITS
DISASSEMBLY AND ASSEMBLY

General Cautions
• Since all parts in control valves are precision • Replace all seals with new ones each time the
machined, carry out disassembly and assembly valves are disassembled.
operations in a clean place. • Spools and section bodies are specially selected for
• Before disassembly, clean the outside surfaces a precise fit. Therefore, if any damage is found in
around the valves. either of these parts, replace the section assembly
• Clean each of the disassembled parts and apply as a unit.
clean hydraulic oil to them. • Be sure to number each section and spool to avoid
• Apply hydraulic oil to sliding surfaces and apply a mistakes during assembly.
thin coating of grease to seals when assembling
them.

Following is an explanation of the control valve

disassembly procedure.
Follow the procedure used to disassemble the control
valve in reverse order when reassembling it.
• Before disassembly, number each section and spool.

Disassembly
Valve Assembly
1. Loosen the nuts and remove the tie rods, then
remove the sections.
Nut: 46.2 ±2 N·m

2. Remove the O-ring.

• The mating surfaces are metal seals, so be
careful not to scratch, bruise or otherwise dam-
age them.

3. Remove the main relief valves and the port relief

valves, then remove the O-rings from the relief
valves.
• Do not disassemble the relief valves unless it is
necessary.
• When using a spanner or adjustable wrench, be
sure to attach it in the place shown in the figure
at right.
Relief valve: 69~78 N·m

G4D223

IV-47 TB53FR
HYDRAULIC UNITS CONTROL VALVE

4. Remove the anti-cavitation valve (1) and remove

the O-ring (2) from the valve.
Plug: 69~78 N·m

5. Remove the load check valve.

• Remove the spring (3), then remove the poppet
(4).

Manually Operated Section

1. Remove the cap screws (5), the cover (6) and the
spool assembly (7).
Cap screw: 8.8~10.8 N·m

2. Loosen the screw (8) from the spool assembly (7).

Screw: 19~22 N·m

TB53FR IV-48
CONTROL VALVE HYDRAULIC UNITS
3. Remove the spring holder (9), spring (10), and
spring holder (9).

4. Remove the seal holder (12), then remove the

backup ring (13) and O-ring (14).

5. Remove the screws on the spool yoke end side of

the section, then remove the seal holder, backup
ring and O-ring.
Screw: 2.5~2.9 N·m

Pilot Operated Section

1. Take out the cap screw (5) and remove the cover
(15), then remove the O-ring (16) from the cover
(15).
Cap screw: 8.8~10.8 N·m

IV-49 TB53FR
HYDRAULIC UNITS CONTROL VALVE

2. Remove the spool from the section.

K3D217

3. Take out the screw (17) and remove the spring

holder (18), spring (19) and spring holder (20).
Screw: 19~22 N·m 20

19
18
17

K3D218

4. a. Take out the cap screws (5) and remove the

cover (21).
b. Remove the O-ring (16) from the cover (21).
Cap screw: 8.8~10.8 N·m 16
21
5

K3D219

TB53FR IV-50
CONTROL VALVE HYDRAULIC UNITS
Main Relief Valve
1. Separate the plug assembly (1) from the housing
assembly (2).
Plug assembly: 69~78 N·m

2. Disassemble the plug assembly (1). 11

a. Remove the lock nut (3), washer (4) and set
screw (5) from the plug (6), then remove the O- 6
ring (7) from the set screw (5).
• During assembly, after installing the set
screw (5), lock the lock nut (3) temporarily, 8
then tighten it after adjusting the pressure.
9
Lock nut: 27.5~31.4 N·m
b. Remove the needle valve (8) and spring (9),
then remove the O-ring (11) from the plug (6). 7
5
4
3 K3D220

3. Disassemble the housing assembly (2).

a. Remove the sleeve (12) and O-ring (13) from
the housing (14).
b. Remove the piston (15), spring (16) and main
poppet (17) from the sleeve (12), then remove
the O-ring (18) and backup ring (19) from the
piston (15).

IV-51 TB53FR
HYDRAULIC UNITS CONTROL VALVE

INSPECTION AND ADJUSTMENT

Checking the Parts

Parts Judgment Criteria Treatment

Housing, • Scratches, rust, corrosion of the portion which slides • Replace
Section Body against the spool.
• Scratches, rust, corrosion of the seal pocket portion of • Replace
the part that enters the spool.
• Scratches, rust, corrosion of the port seal portion which • Replace
is in contact with the O-ring.
• Scratches, rust, corrosion of the seal portion of the relief • Replace
valve, etc.
• Other damage which could be a hindrance to correct • Replace
function.
Spool • Scratch marks like being clawed around the outer cir- • Replace
cumference sliding portion.
• Scratches on the portion that slides against the seals on • Replace
both ends.
• Spool not operating smoothly. • Repair or replace.
Load Check Valve • Imperfect sealing due to damage to the valve or spring. • Repair or replace.
• Does not catch, but operates lightly when inserted in the • Normal
section body and operated.
Around Springs • Rust, corrosion, deformation, breakage or other marked • Replace
damage to the spring, holder or cover.
Around Spool Seal • Oil leaking to the outside. • Repair or replace.
• Rust, corrosion or deformation of the seal holder. • Repair or replace.
Main Relief Valve, • External rust, damage. • Replace
Port Relief Valve, • Damage to valve seat contact surface. • Replace
Anti-Cavitation Valve • Damage to poppet contact surface. • Replace
• Abnormality in the spring. • Replace
• O-rings, backup rings, seals • As a rule, all these
should be replaced.

Adjusting the Main Relief Valve Pressure

1. Install a pressure gauge in the following pressure
sensor port.
• Control valve pressure sensor port.
“II. Specifications, Standards for Judging
Performance”
2. Run the pump at the rated speed.
3. Operate the control valve’s cylinder spool over its 1
full stroke and read the value indicated by the
2
pressure gauge.
4. Turn the set screw (1) while watching the pres-
sure gauge to adjust.
Turning it to the right increases the set pressure.
Turning it to the left decreases the set pressure.
5. After completing the pressure adjustment, tighten
the lock nut (2) while holding the set screw (1) so
it won’t turn.
Operate the relief valve again and check if the
pressure is stabilized. L2B017

TB53FR IV-52
CONTROL VALVE HYDRAULIC UNITS
TROUBLESHOOTING

The following items are a list of all the problems that compound the trouble. It is therefore desirable to
might occur individually, but in actual practice, 2 or proceed so that the causes can be eliminated one at a
3 of these problems might occur simultaneously to time.

Symptom Probable Causes Remedy

Oil leaks from spool seal. • Seal is scratched or the seal lip is worn • Replace with a new part.
due to long use.
• Spool’s seal sliding portion was dam- • Repair or replace the spool.
aged by some external cause (bruise,
scratch, etc.).
• Seal bulged out and the cover was in- • Return to the correct shape and check
stalled in a warped state. for eccentric wear of the seal lip.
• Paint adhered to the sliding portion of • Remove paint with paint thinner or re-
the spool’s seal portion during painting. move it mechanically. However, at this
time, be careful not to damage the spool
surface or the seal lip.
• Tank circuit’s pressure became high • Eliminate the factors causing excessive
and exceeded the pressure level that the flow resistance.
seal was capable of withstanding.
Spool’s sliding is not • Foreign matter is biting into the spool’s • Overhaul and repair or replace.
smooth. sliding surface.
• Oil film between the spool and body • Use some method to lower the oil tem-
disappears due to abnormally high oil perature or if the relief valve is operat-
temperature. ing frequently, investigate the cause
and reduce the frequency.
• Lubrication is improper due to deterio- • This could be alleviated by simply re-
rating oil. placing the hydraulic oil, or it could
require an overhaul of the circuit.
• Spool is worn from long use or due to • Check the spool’s diameter and con-
pressure bearing on one side only. sider the necessity of replacement.
• Spool is bent from externally applied • Check the spool’s straightness and other
pressure. factors, then repair or replace.
• Entire valve is strained due to strain in • Loosen the installation bolts, then cut
the installation face. the installation face and edge and check.
• Valve was used at a pressure or a flow • In the case of pressure, check with a
volume which was out of specification. pressure gauge. In the case of flow
volume, check by the actuator’s speed
of movement and the capacity.
• Bolts used to assemble the valve were • Check if the assembly bolts are tight-
tightened excessively. ened to the specified torque. If the torque
deviates markedly from the specified
torque, tighten them again.
• Oil is accumulating in the cover (the • The spool is leaking oil, so when the
side with a spring or a detent) opposite spool moves, oil leaks from the cover.
the side where the spool operates. After confirming this, replace the seal.
Cylinder drops while • Foreign matter is biting into the load • Disassemble and check, then overhaul
shifting to a lift operation. check valve seat or large scratches were or replace.
made by foreign matter biting into the
valve's seat previously.

IV-53 TB53FR
HYDRAULIC UNITS CONTROL VALVE

Symptom Probable Causes Remedy

Can’t be held in the spool • Could be mistaken for a great amount of • Check if it isn't just the cylinder’s natu-
neutral position (cylinder leakage in the cylinder. ral drop when the cylinder is held. If the
drops). problem is in the cylinder, disassemble
and repair it.
• The gap between the spool and body is • Replace the spool or replace the valve
large, so the amount of oil leaking from block assembly.
the spool is great.
• Spool won’t return completely to the • Manually Operated :
neutral position. Check if there is something interfering
with the link mechanism.
Pilot Operated:
Check the pilot pressure.
• Foreign matter is biting into the port • Disassemble and check, then overhaul
relief valve seat or the anti-cavitation or replace.
valve seat and oil is bypassing. Or a seat
is damaged.
The load won’t move. • Foreign matter is biting into the relief • Disassemble and check, then overhaul
(Pressure won’t increase.) valve seat and oil is bypassing. Or the or replace.
seat is damaged.
• The relief valve’s adjustment screw is • Try tightening the adjustment screw. If
loose. it is loose, correct the setting and tighten
the lock nut securely.
• Foreign matter is biting into the port • Disassemble and check, then overhaul
relief valve seat or the anti-cavitation or replace.
valve seat and oil is bypassing. Or a seat
is damaged.
• Spool stroke is not the specified stroke. • Manually Operated:
Check if there is something interfering
with the link mechanism. Check if a pin
or a pin hole in the link connection is
worn.
Pilot Operated:
Check the pilot pressure.
• Pump is damaged and no oil is dis- • Check if the pump is abnormal or not. If
charged. the pump is bad, replace it. Check if the
cause of the abnormality is air being
sucked in, deterioration of hydraulic oil
or shafts not centered, etc.
Load doesn’t move. (Pres- • The load is too heavy. • Compare with an object of the specified
sure rises.) weight.
• Mechanical resistance of connecting • Check and replenish hydraulic oil, etc.,
parts is great regardless of the hydraulic modify or repair.
pressure in the operating unit.
• A large piece of foreign matter is trapped • Find the affected place and repair it.
in the circuit or a pipe is bent, causing
great resistance.

TB53FR IV-54
CONTROL VALVE HYDRAULIC UNITS

Symptom Probable Causes Remedy

Load doesn’t move. (Pres- • Spool stroke is not the specified stroke. • Check if there is something interfering
sure rises.) with the link mechanism. Check if a pin
or a pin hole in the link connection is
worn or not.

IV-55 TB53FR
HYDRAULIC UNITS CONTROL VALVE

TB53FR IV-56
SOLENOID VALVE HYDRAULIC UNITS
SOLENOID VALVE
CONSTRUCTION

 



  

    
 
     
 
 


 
 

   
   
    
 
 


  
  



1. Shim 9. Body
2. Spring 10. Spool
3. Plug 11. Spool
4. Spool 12. Ring
5. Sleeve 13. Plug
6. Spring 14. O-ring
7. Orifice 15. O-ring
8. Solenoid 16. O-ring

IV-57 TB53FR
HYDRAULIC UNITS SOLENOID VALVE

OPERATION
SOL A, B Auxiliary Hydraulics
This valve is a compound valve consisting of sole-
noids that control the operation as follows: Solenoids SOL 1 Stops Left Offset
A and B switch the auxiliary hydraulics. Solenoid 1 SOL 2, 3 Stops Boom Raise,
stops the boom offset.
Decelerates Boom Raise
Solenoids 2 and 3 are operated to prevent the boom
from interfering with the cab when the boom is raised.
These solenoids actuate the pressure reducing valve
to decelerate the boom in the deceleration area when
the boom is raised and actuate the flow control valve
in the boom stop area to relieve the shock when the
boom is stopped.

Solenoids A, B, 1
When the solenoid is not electrified
The oil in the port P is blocked by the spool (1). As the T
port A and port T are connected, the downstream pilot P
circuit has the same pressure as the tank pressure.

C4D901

When the solenoid is electrified

A magnetic field is generated around the coil. The
push rod (2) is pulled down to press down the spool
2
(1), then the oil in port P flows into port A and conveys P
the pressure to the downstream pilot circuit.

C4D902

TB53FR IV-58
SOLENOID VALVE HYDRAULIC UNITS
Solenoids 2 and 3
The solenoids 2 and 3 are turned on until the boom is
raised and enters the boom raise decelerating area.
When the boom enters the boom raise decelerating
area, only the solenoid 3 turns off to actuate the
pressure reducing valve. When the boom advances
further into the boom raise stop area, the solenoid 2 is
also turned off to actuate the flow control valve.

When the boom is raised

5
4

1 2
SOL2
SOL3

T
B2
A2

L2D901

The spools (1) and (2) of the solenoids 2 and 3 are

pressed down by the magnetic field around the coil.
The pilot pressure from the pilot valve (3) is applied
through the port A2, passages (4) and (5), port B2 and
to the boom section (6) of the control valve. This
causes the boom to be raised.

IV-59 TB53FR
HYDRAULIC UNITS SOLENOID VALVE

When the boom raise is decelerated (pressure reducing valve)

3 7

4
B 9 A B 9 A
1 2
SOL2
SOL3
5

T
B2
A2

L2D902

When the boom enters the boom raise decelerating

area, the solenoid 3 is turned off and the spool (2) is
shifted upward to connect the passage (7) and the tank
passage (8), making the pressure in the chamber A the
same as the tank pressure.
When the pressure in the chamber B increases to reach
the setting value, the spool (9) of the pressure reduc-
ing valve is shifted to the right. At this time, part of the
hydraulic oil to be supplied from the port A2 to the
port B2 flows from the chamber B through the pas-
sage (7) and enters the passage of the tank (8). When
the pressure in the chamber B is reduced to the setting
value, the spring force shifts the spool (9) to the left,
increasing the pressure in the chamber B.
By repeating the above operation, the pressure in the
chamber B is kept at a constant reduced level and
applied to the boom section of the control valve (6).
This pushes back the spool of the control valve (6) to
the same position as where the set pressure is applied,
and reduces the flow of the hydraulic oil to decelerate
the boom raise.

TB53FR IV-60
SOLENOID VALVE HYDRAULIC UNITS
When the boom raise is stopped (flow control valve)

1 10 2
SOL2
C SOL3
5
11
12
B2
A2
D

13 14

L2D903

When the boom enters the boom raise stop area, the hole of the plunger (11) is throttled by the land section
solenoid 2 is turned off, and the spool (1) of the (14). This generates the passing resistance that pro-
solenoid is shifted upward. This causes the spool (1) duces a force in the chamber D that acts to shift the
to block the pilot pressure that is applied from the pilot plunger (11) upward.
valve (3) through the passages (4) and (5), port B2, As the force that acts to shift the plunger (11) down-
and to the boom section (6). ward by the passing resistance generated through the
The hydraulic oil led to the boom section (6) of the orifice (12) and the force that acts to shift the plunger
control valve passes through the port B2, passage (11) upward by the passing resistance generated
(10), and plunger (11) to enter the chamber C. The through the throttled side hole are balanced, the flow
hydraulic oil then flows little by little through the is always kept constant.
orifice (12) and the side hole to the tank passage (13). Therefore, when the boom raise is stopped, the pilot
When the hydraulic oil passes through the orifice pressure of the boom section of the control valve is
(12), passing resistance (pressure) is generated. This gradually reduced by the flow control, and the pos-
pressure tries to shift the plunger downward. sible shock at the time of the boom stop is relieved.
When the plunger (11) is shifted downward, the side

IV-61 TB53FR
HYDRAULIC UNITS SOLENOID VALVE

DISASSEMBLY AND ASSEMBLY

General Cautions
• Carry out disassembly and reassembly operations • The spool and body are selectively fitted, so if one
in a clean place and place disassembled parts in is found to be damaged, replace the valve assem-
clean containers. bly.
• Before disassembly, clean thoroughly around the • Apply a thin coating of hydraulic oil to sliding
ports and remove paint or thread lock, etc. from all surfaces and a thin coating of grease to seals when
joints with a wire brush. assembling them.
• Clean the disassembled parts with appropriate clean- • Replace seals with new parts each time disassem-
ing oils. bly is done.

The following describes the disassembly procedure.

For assembly, refer to the construction diagram and
follow the disassembly procedure in the reverse or-
der.

Disassembly 
Pressure Reducing Valve
1. Fix the body and loosen the plug (1).
Plug: 49 N·m

2. Remove the O-ring from the plug (1).

.",'

3. Remove the spring (2) and plunger (3).

• Be careful not to damage or lose the pressure
adjusting shims (4).
!
"

.",'

Flow Control Valve

1. Remove the plugs (8) from both sides of the body. &
Plug: 23.5 N·m '
2. Remove the O-ring from the plug (8). 
3. Remove the springs (9) and plunger (10).

'

& .",'!

TB53FR IV-62
SOLENOID VALVE HYDRAULIC UNITS
Solenoid
1. Loosen the cap screws and remove the solenoid
coil (5). #
• Put matching marks on the solenoid and the
body so that they can be aligned when assem-
bling.
• Take care not to miss the push rod.
Cap screw: 3.92 N·m

2. Remove the O-ring from the solenoid coil (5).

.",'"

3. Remove the spool (6) and sleeve (7) from the

body. $
• Record the positions of the spool, sleeve and
the body hole so that they can be aligned when
assembling.
• To take out the spool, hook the small orifice at
the end of the spool using a tool such as a %
scriber.
• To remove the sleeve, turn the body upside
down and lightly tap it.

.",'#

IV-63 TB53FR
HYDRAULIC UNITS SOLENOID VALVE

INSPECTION AND ADJUSTMENT

Checking the Parts

Parts Judgment Criteria Treatment

Solenoid coil • When the solenoid is burned, short-circuited, or has a wire • Replace
break
• Wiring short-circuit or wire break • Replace
Body • Scratches, rust, or corrosion at the sliding parts with the spool • Replace
• Scratches, rust, or corrosion of the seal part in contact with the • Replace
O-ring
• Other damage considered to impair the normal functions • Replace
Spool, plunger • Damage on the outer circumference which catches a fingernail • Replace
• No smooth movement • Adjust or replace
Spring • Rust, corrosion, deformation, breakage, or other notable dam- • Replace
age
O-Ring  • Replace

TROUBLESHOOTING

Symptom Probable Causes Remedy

Solenoid valve does not • Wiring short-circuit or wire break • Replace
operate. • Solenoid coil short-circuit or wire break • Replace
• Catching of foreign matter by the spool • Overhaul and repair or replace.
• Damage on the outer circumference of the spool • Overhaul and repair or replace.
• Catching of foreign matter by the plunger • Overhaul and repair or replace.
• Damage on the outer circumference of the plunger • Overhaul and repair or replace.
Oil leakage from solenoid • Damaged O-ring • Replace
valve, cover, or relief • Damaged O-ring at the emergency manual but- • Replace
valve to the outside. ton of the solenoid valve
Pressure does not rise. • Catching of foreign matter by the relief valve • Clean or replace.

TB53FR IV-64
PILOT VALVE HYDRAULIC UNITS
PILOT VALVE
CONSTRUCTION

20

4
5

3 11
24
21
12

23 17
6

25
7.8
1
2 18 22
16
19
15
14
9

10

7.8 13 26 27
C4D300

1. Retainer 10. Port Plate 19. Spring

2. Spring Holder 11. Push Rod 20. Nut
3. Push Rod 12. Spring Holder 21. Sleeve
4. Joint 13. Piston 22. Cap Screw
5. Cam 14. Spool 23. Cap Screw
6. Plate 15. Wire Ring 24. U-Packing
7. Shim 16. Spring 25. O-ring
8. Shim 17. Spring 26. O-ring
9. Casing 18. Spring 27. O-ring

IV-65 TB53FR
HYDRAULIC UNITS PILOT VALVE

OPERATION

The pilot valve casing contains a vertical shaft hole The casing also contains an inlet port for hydraulic oil,
with a reducing valve incorporated into it. When the port P (primary pressure), and an outlet port, port T
handle is tilted, the push rod and spring seat are (tank), and secondary pressure is taken from 4 ports,
pushed down changing the secondary pressure spring’s port 1, port 2, port 3 and port 4, on the bottom of the
pressure. vertical shaft hole.

WHEN TILTED WHEN IN NEUTRAL

When the Handle is in Neutral When the Handle is Tilted

In this case, the force of the secondary pressure setting When the handle (1) is tilted and the push rod is
spring, which determines the pilot valve’s output pushed, the spool moves downward and port P and
pressure (secondary pressure), is not transmitted to port A are joined. The oil in the pilot valve pump flows
the spool. Therefore, the spool is pushed up by the out to port A, generating pressure.
return spring and is in the output port C position When the pressure in port A is the same as the set force
shown above, with oil not flowing between port P and of the spring (set pressure), there is a balance between
the output port C but flowing between the T port and the hydraulic pressure and the spring force.
output port C. When the pressure in port A is greater than the set
pressure, port A and port P close and port A and port
T open.
When the pressure at port A is lower than the set
pressure, port A and port P open and port A and port
T close.
In this way, the secondary pressure is kept constant.

TB53FR IV-66
PILOT VALVE HYDRAULIC UNITS
DISASSEMBLY AND ASSEMBLY

General Cautions
• Since all parts in the pilot valve are precision • Replace all seals with new ones each time the pilot
machined, carry out disassembly and reassembly valve is disassembled.
operations in a clean place and take special care not • During assembly, remove all the foreign matter
to scratch the parts. from each part and check them to make sure there
• Before disassembly, clean the outside surfaces of are no burrs, bruises using or other marks on them.
the pilot valve. Remove all burrs and bruises using an oil stone.
• Clean each of the disassembled parts and apply • Apply thin coating of grease to seals when assem-
clean hydraulic oil to them. bling them.

Disassembly 1
1. Remove the nut (1) and separate the joint from the
cam (2).
2
• Fix the valve to the vise using a copper plate or
lead plate. 3

2. Remove the joint (3).

C4D301

3. Loosen the cap screws at the bottom and remove

the port plate (4).

4. Remove the four pistons (5), one O-ring (6), and

six O-rings (7).
5
6

7 4

C4D302

5. Loosen the cap screws and remove the plate (8).

8
6. Remove the push rods (9) together with the sleeves
(10).
• The push rods for port 1 and port 3 are different 9
from those for port 2 and port 4. Store them
carefully so that they can be restored at the 10
same positions when assembling.

C4D303

IV-67 TB53FR
HYDRAULIC UNITS PILOT VALVE

7. Remove the O-ring (11) and U-packing (12) from

the sleeve (10). 12

10

11

C4D304

8. Remove the spool assembly (13) and spring (14) 13

from the casing.
• The spool assemblies and springs for port 1
and port 3 are different from those for port 2 14
and port 4. Store them carefully so that they can
be restored at the same positions when assem-
bling.

C4D305

9. Disassemble the spool assembly.

a. Push down the spring holder (15) and remove
C
the retainer (17) from the spool (18).
D
b. Remove the spring holder (15) and spring (19)
from the spool (18).
17
• Be careful not to lose the pressure adjusting
15
shim (20) if assembled.
19
20
18

C4D306

TB53FR IV-68
PILOT VALVE HYDRAULIC UNITS
Assembly
1. Assemble the spring assembly.
A
a. Fit the spring (19) to the spool (18) and install
the spring holder (15). 15
• Be careful of the direction of the spring B
19
holder.
A: Make the side with the deeper hole up. 18
B: Make the side with the shallow hole down.

C4D307

b. Push down the spring holder (15) and fit the

retainer (17) to the spool (18).
C
• Be careful of the direction of the retainer.
D
C: Make the side with the sharp corner up.
D: Make the side with the round corner down. 17
15
19
20
18

C4D306

2. Install the spring (14) and spool assembly (13) in 13

the casing.
• Install them at the same positions as previously
assembled. 14
• Be careful not to damage the spool hole.

C4D305

3. Install the O-ring (11) and U-packing (12) in the 12

sleeve (10).
• Be careful of the direction of the U-packing.

10

11

C4D304

IV-69 TB53FR
HYDRAULIC UNITS PILOT VALVE

4. Assemble the push rods (9) and sleeves (10), and

mount them on the spool assemblies in the casing.
• Install them at the same positions as previously 8
assembled.
• Be careful not to damage the parts by pushing
them too strongly. 9

10
5. Mount the plate (8) and tighten the cap screws.
Cap screw: 23.5 ±2 N·m

C4D303

6. Turn the casing upside down to make the push

rods the lower side and insert the four pistons (5)
into the spool holes. 4
• Let the side A with the smaller diameter (un-
polished side) of the piston be positioned in the 6 7
back of the holes. 5
A

7. Install one O-ring (6), six O-rings (7) and the port
plate (4) in the casing and tighten them with the
cap screws.
Cap screw: 23.5 ±2 N·m
C4D308

8. Reverse the casing again to the original position 1

and install the joint (3).
Joint: 49 ±4.9 N·m
2
• Apply Loctite #242 to the joint screws.
3

9. Tighten the cam (2) with your fingers until it

touches the push rod. Loosen the cam at an angle
of around 45° before tightening the nut (1).
Nut: 49 ±4.9 N·m
IMPORTANT: Never tighten the nut without
loosening the cam, otherwise the cam will rotate C4D301

with the nut, keeping the push rods pressed. This

will generate secondary pressure in the neutral
position that might cause erroneous operation.

10. Apply grease to the cam, push rods and joint

rotating section.

TB53FR IV-70
PILOT VALVE HYDRAULIC UNITS
INSPECTION AND ADJUSTMENT

Checking the Parts

Parts Judgment Criteria Treatment

O-ring  • Replace
Seal  • Replace
Seal Washer  • Replace
Spool • Wear on sliding portions is 10 µm or greater compared to non- • Replace
sliding portions
• Scratches on sliding portions • Replace
• Spool doesn’t move smoothly • Repair or replace
Push Rod • Front end is worn 1 mm or more • Replace

• Scratches in the sliding portion • Replace

Plug • Seal is imperfect due to damage • Repair or replace
Operating Portion • Tightening is loose at the pin, shaft or joint of the operating • Tighten to the speci-
portion, with looseness of 2 mm or greater fied torque
• Due to wear, etc. tightening is loose at the pin, shaft or joint of • Replace
the operating portion, with looseness of 2 mm or greater
Casing, • Scratches, rust or corrosion on the spool and sliding portion • Replace
Port Plate • Scratches, rust or corrosion on seal portions which come in • Repair or replace
contact with the O-ring

IV-71 TB53FR
HYDRAULIC UNITS PILOT VALVE

TROUBLESHOOTING

Symptom Probable Causes Remedy

Secondary pressure doesn’t • Primary pressure is insufficient • Keep the primary pressure
rise • Spring is damaged or permanently • Replace the spring
deformed
• The clearance between the spool and • Replace the spool and casing assem-
casing is abnormally large bly
• There is looseness in the handle • Disassemble and reassemble, or re-
place the handle
Secondary pressure doesn’t • Sliding parts are catching • Repair or replace
stabilize • Tank line pressure fluctuates • Remove the abnormal portions of the
tank line
• Air gets mixed into the piping • Operate the machine several times
and bleed out the air
Secondary pressure is high • Tank line pressure is high • Remove the abnormal portions of the
tank line
• Sliding parts are catching • Repair or replace

TB53FR IV-72
PILOT VALVE HYDRAULIC UNITS
PILOT VALVE (Offset)
CONSTRUCTION

1 20 6 9 16 7 4 18 15 3
19

13
2
14
11á10
8
17á12á5
21

L2D300

1. O-ring 8. Spring 15. Cap Screw

2. O-ring 9. Boot 16. Set Screw
3. Cover 10. Shim 17. Washer
4. Push Rod 11. Shim 18. Washer
5. Shim 12. Shim 19. Spring Pin
6. Cam 13. Spring Holder 20. Ball
7. Pin 14. Spring 21. Spool

IV-73 TB53FR
HYDRAULIC UNITS PILOT VALVE

OPERATION

“IV-66”

DISASSEMBLY AND ASSEMBLY

General Cautions
“IV-67”

The following describes the disassembly procedure.

For assembly, refer to the construction diagram and
follow the disassembly procedure in the reverse or-
der.

Disassembly
1. Remove the boot from the cover.
• Use a copper or iron sheet to fasten the valve to
the vice.
• Apply grease to the cam and push rods.

L2D301

2. Remove the set screw.

Set screw 4.9 N·m
• Apply Loctite #262 to the set screw.

L2D302

3. Remove the cam pin, then remove the cam (1).

L2D303

TB53FR IV-74
PILOT VALVE HYDRAULIC UNITS
4. Loosen the cap screws and remove the cover (2).
• The cover and plug will rise from the surface if
the rebound spring is too strong, so loosen the
cap screws alternately so that the cover is flat.
2
• Mark the cover and casing so that they can be
reassembled in the same positions.
Cap screw 23.5 N·m

5. Remove the O-rings from the casing (3). 3

L2D304

6. Remove the push rods (4) together with the cover

(5). 5

7. Remove the O-rings (6) from the cover (5).

• Be careful not to damage the push rod hole.

L2D305

8. Remove the spool assembly (7) and spring (8)

from the casing.
• Never disassemble the spool assembly as the
pressure has been adjusted by the shim. 7

L2D306

IV-75 TB53FR
HYDRAULIC UNITS PILOT VALVE

INSPECTION AND ADJUSTMENT

“IV-71”

TROUBLESHOOTING

“IV-72”

TB53FR IV-76
CYLINDERS HYDRAULIC UNITS
CYLINDERS
CONSTRUCTION

Boom Cylinder

20 24 2 12 6 13 1 4 3 4 5 14 15 7 16 17 18 19 24 20

11 9
23
10 21 22 8

J1D400

1. Rod Packing 7. Piston Packing 13. Bushing 19. Ball

2. Dust Seal 8. Tube 14. Cushion Bearing 20. Dust Seal
3. O-ring 9. Bushing 15. Piston 21. Pipe
4. Backup Ring 10. Piston Rod 16. Wear Ring 22. Bolt
5. O-ring 11. Bushing 17. Nut 23. Washer
6. O-ring 12. Rod Cover 18. Set Screw 24. Grease Nipple

Arm Cylinder

24 29 2 12 6 13 1 4 3 4 5 15 14 16 7 17 18 19 22 21 20 23 24

11 9

10 8
27 28 25 26
J1D401

1. Rod Packing 9. Bushing 17. Wear Ring 25. Pipe

2. Dust Seal 10. Piston Rod 18. Set Screw 26. Nipple
3. O-ring 11. Bushing 19. Ball 27. Bolt
4. Backup Ring 12. Rod Cover 20. Cushion Bearing 28. Washer
5. O-ring 13. Bushing 21. Cushion Seal 29. Grease Nipple
6. O-ring 14. Cushion Bearing 22. Snap Ring
7. Piston Packing 15. Spacer 23. Stopper
8. Tube 16. Piston 24. Dust Seal

IV-77 TB53FR
HYDRAULIC UNITS CYLINDERS

Bucket Cylinder

18 19 15 11 12 13 20 22 2 1 21 9 10 14 8 3 7 17 19

16 5 6 4 16
K3D402

1. Tube 7. Dust Seal 13. Piston Packing 19. Dust Seal

2. Piston Rod 8. O-ring 14. Backup Ring 20. O-ring
3. Rod Cover 9. Packing Holder 15. Set Screw 21. Snap Ring
4. Bushing 10. O-ring 16. Bushing 22. Packing Holder
5. Rod Packing 11. Piston 17. Grease Nipple
6. Backup Ring 12. Wear Ring 18. Grease Nipple

Dozer Blade Cylinder

19 6 3 10 9 4 7 8 5 2 1 11 13 12 17 15 16 14 20 18

21
J1D403

1. Tube 7. O-ring 13. Wear Ring 19. Grease Nipple

2. Piston Rod 8. Backup Ring 14. Nut 20. Grease Nipple
3. Rod Cover 9. O-ring 15. Set Screw 21. Dust Seal
4. Bushing 10. Lock Washer 16. Ball
5. Rod Packing 11. Piston 17. Shim
6. Dust Seal 12. Piston Packing 18. Bushing

TB53FR IV-78
CYLINDERS HYDRAULIC UNITS
Offset Cylinder
Serial No. 15810005~15810018

2 12 5 13 1 4 3 15 6 14 16 17
7 7

11 9

10 8
J1D404

1. Rod Packing 6. Piston Packing 11. Bushing 16. Set Screw

2. Dust Seal 7. Dust Seal 12. Rod Cover 17. Ball
3. O-ring 8. Tube 13. Bushing
4. Backup Ring 9. Bushing 14. Piston
5. O-ring 10. Piston Rod 15. Wear Ring

Serial No. 15810019~

2 12 5 13 1 6 3 6 4 15 14 16 7 17 18 19
20 20

11 9

10 8
J1D405

1. Rod Packing 6. Backup Ring 11. Bushing 16. Piston

2. Dust Seal 7. Piston Packing 12. Rod Cover 17. Wear Ring
3. O-ring 8. Tube 13. Bushing 18. Set Screw
4. O-ring 9. Bushing 14. Cushion Bearing 19. Ball
5. O-ring 10. Piston Rod 15. Spacer 20. Dust Seal

IV-79 TB53FR
HYDRAULIC UNITS CYLINDERS

OPERATION

Hydraulic oil flowing alternately in and out of the oil

outlet and inlet on both sides (head and rod sides) of
the piston acts on the piston and its force causes the
piston to move back and forth.
In cylinders equipped with a cushion mechanism, the
shock resulting from the piston colliding with the
cover at the stroke end acts on that mechanism and is
dampened by it.

Cushion Mechanism

1 3 2
A

4
DETAIL PORTION "A"

L1-D406E

When the piston (1) nears the stroke end, just before
it collides with the cover (2), if the cushion bearing (3)
that precedes it enters the inner diameter portion of the
cover, the oil in the back of the piston is restricted by
the cushion bearing (3) and the clearance (4) of the
cover inner diameter portion. This causes the piston’s
(1) back pressure to rise and slows the piston’s speed.

TB53FR IV-80
CYLINDERS HYDRAULIC UNITS
DISASSEMBLY AND ASSEMBLY

Special Tools
See the table of special tools at the back of this section
for the jigs and tools used for disassembly and assem-
bly.

General Cautions
• Carry out disassembly and assembly in a clean • Replace all seals with new parts.
place and place the disassembled parts in a place • Replace the piston nuts, set screws, steel balls,
where they will be kept clean at all times. stoppers and snap rings with new ones each time
• Before disassembly, clean the outside surface of they are disassembled.
the cylinder thoroughly. • Apply a thin coating of hydraulic oil to seals before
• In the disassembly and assembly operations, be fitting them in place.
careful not to scratch any part. Take particular • After fitting, make sure the O-rings are not twisted.
caution with the sliding surfaces of parts. • Apply clean hydraulic oil to each sliding portion
• Clean all disassembled parts thoroughly with clean- before assembling them.
ing oil.

In this manual, the procedure for the arm cylinder is

described. When necessary, the points which are
different in other cylinders are mentioned.

Disassembly
Cylinder Assembly
1. Fasten the clevis of the tube in a vice and place the
other end on a support block made of wood to
fasten the cylinder in a horizontal condition.

2. Drain out hydraulic oil remaining in the cylinder.

• Move the piston rod gently to prevent the
hydraulic oil from spraying out and scattering
all over.

3. Free the locked portion of the rod cover.

• Since the lock is integrated with the cylinder
tube, be careful not to bend it or to scratch it
when the lock is being freed.

4. Loosen the rod cover.

• The piston rod should be pulled out approxi-
mately 200mm beforehand.
• Measures should be taken to prevent the piston
rod from being hit.

IV-81 TB53FR
HYDRAULIC UNITS CYLINDERS

5. Pull the piston rod assembly out of the tube.

• Use a wooden block (1) so as not to scratch the
sliding surface, and pull the assembly straight
out.

Piston Rod Assembly

1. Fasten the piston rod assembly securely in a level
position.

2. Remove the piston.

a. Take out the set screw (2) and remove the steel
ball (3).
• The set screw is staked at 2 places with a
punch, so grind off the staked portions using
a hand drill.
b. Loosen the piston nut (6) and remove it.
• Use a wrench with a hydraulic jack (5).

6 8
7
6
5
J1D407

3. Remove the cushion bearing (7) and spacer (8). 9

10

2
3
J1D406

4. Remove the cushion bearing.

a. Remove the snap ring (9).
b. Move the cushion bearing (10) and remove the
stopper (11).
c. Pull out the cushion bearing (10).
d. Remove the cushion seal (12).

TB53FR IV-82
CYLINDERS HYDRAULIC UNITS
5. Remove the rod cover assembly.

Piston
1. Remove the wear ring (27), then remove the
piston packing (28).
• Spread the wear ring at the cut portion the
minimum amount necessary for it to be re-
moved. Remove it in the direction of the shaft.
• Either cut the piston packing off or use a flat
bladed screwdriver, etc. to take it off.

Rod Cover
1. Remove the O-ring (34) from the outer diameter
of the rod cover, then remove the backup ring
(35).

2. Remove the rod packing.

K3D409

IV-83 TB53FR
HYDRAULIC UNITS CYLINDERS

3. Remove the dust seal (42).

• Tap alternately on several points around the
circumference on the inside of the metal ring,
pushing it out a little at a time to remove it.

4. Remove the bushing.

• Since the bushing has been pressure fitted
tightly in the rod cover, it is impossible to take
it out. First use a lathe to grind down the inside
portion until only a thin piece remains, then
insert a copper spatula strongly and pry it out
to remove it.

Clevis
1. Remove the dust seals from the tube and piston
rod.

2. Remove the bushings using a setting tool (43).

TB53FR IV-84
CYLINDERS HYDRAULIC UNITS
Assembly
Clevis
1. Using installation jig (B), pressure fit the bush-
ings (44) in the piston rod and tube.

2. Using a setting tool (45), install the dust seals.

Rod Cover
1. Using an installation jig (A), pressure fit the
bushing.
• Hydraulic fluid should be applied to the inside
surface of the rod cover before assembly.
• After installation, make sure there are no level
differences with the bushing.

2. Install the rod packing.

K3D409

IV-85 TB53FR
HYDRAULIC UNITS CYLINDERS

3. Install the dust seal (42).

• In the case of a dust seal with a metal ring
around the outer circumference, use a setting
tool (46) to install it.

4. Install the backup ring (35) and fit the O-ring (34).
• The cut portions of the backup ring should
overlap correctly.

Piston
1. Assemble the piston assembly.
a. Fit the O-ring (50).
• If the O-ring is twisted after it is fitted,
correct it.

b. Cover the piston with the sliding jig (C), then

using the fitting jig (D), insert the slipper ring
(51) rapidly.

TB53FR IV-86
CYLINDERS HYDRAULIC UNITS
c. Since the slipper ring (51) is extended when it
is installed, correct it using the corrective jig
(E).

2. Install the wear ring (27).

a. Spread the wear ring (27) at the cut portion the
minimum amount necessary, installing it on
the piston from the shaft direction.

Piston (in two pieces) 30 31 32 31

1. Install the back ring (30), the backup ring (31),
and the slipper ring (32) on the piston (13).
13 5

E5D432

2. Install the wear ring (11) on the piston (13) and 11

the packing holder (5).
• Widen the cut part of the wear ring (11) only as
far as required, and install it from the axial
direction on the piston.

13

5 12

E5D415

IV-87 TB53FR
HYDRAULIC UNITS CYLINDERS

Piston Rod Assembly

1. Fasten the piston rod so that it is flat and install the
rod cover.
• Cover the piston rod thread with tape, etc., to
protect the seals from being scratched.

2. Install the cushion bearing.

a. Install the cushion seal (12).
• Set the side with the slits facing the screw
side.
b. Install the cushion bearing (10).
• Be sure to set with the flat side (A) in the
proper direction.
c. Install the stopper (11) on the piston rod, and
move the cushion bearing (10).
7 8
d. Install the snap ring (9). 6

3. Install the spacer (8) and cushion bearing (7).

• Set the side of the cushion seal with the slits 9
facing the screw side. 10
• Be sure to set with the flat side (A) of the
cushion seal in the proper direction.

2
4. Install the piston. 3
a. Install the piston nut (6) and tighten it. J1D406

Piston nut: Refer to the table below.

b. Insert the steel ball (3).
c. Tighten the set screw (2) and caulk it at two
places with a punch.
Set screw: Refer to the table below.

Piston Nut, Set Screw Unit: N·m

Place Piston Nut Set Screw
Boom Cylinder 2650 31.5
Arm Cylinder 1510 16.2
Bucket Cylinder 824 15.6
Dozer Blade Cylinder 2256 31.5
Offset Cylinder 2060/1960* 31.5/16.2*
* Serial No. 15810019~

TB53FR IV-88
CYLINDERS HYDRAULIC UNITS
Cylinder Assembly
1. Fasten the tube in a horizontal position, then
insert the piston rod assembly in the tube.
• During insertion, align the center of the piston
rod with the center of the tube, inserting it
straight so the seals will not be scratched.

2. Tighten the rod cover.

• Apply Three Bond #1901 or the equivalent to
the rod cover tread.
Rod cover Unit: N·m
Boom Cylinder 834
Arm Cylinder 530
Bucket Cylinder 539
Dozer Blade Cylinder 834 ±191.2
Offset Cylinder 647

3. Bend the lock rib on the tube down in a notch of

the rod cover to lock it.

IV-89 TB53FR
HYDRAULIC UNITS CYLINDERS

INSPECTION AND ADJUSTMENT

Inspection after Disassembly

Clean each part thoroughly with cleaning oil, then
carry out the following checks. When a cylinder has
been disassembled, replace all the seals with new
ones.

Piston Rod
• Replace the rod if there are cracks. Measuring the Bend
• If the threads are damaged, repair them or replace
it.
• If the plating layer of the plated portion is broken,
rusted or scratched, replace it.
• If the rod is bent more than the limit of 1 mm in 1
m, replace it. (Measure by the method shown in the
figure at right.)
If the bending of the rod is within the above limit,
yet is bent a lot in a small distance so that it won’t a. Support the portion of the rod with the same
move smoothly, replace the rod if it makes a diameter at both ends on V-blocks.
squeaking sound in the operation test after reas- b. Set a dial gauge at the center between the two
sembly or if it catches during movement. blocks.
• If the inner diameter of the clevis bushing is worn, c. Rotate the rod and take a reading of the maximum
replace the bushing. and minimum runout indicated by the dial gauge.

Tube
• If there are cracks in the welded portion, replace it.
• Replace the tube if the inside surface is scratched
or if it leaks hydraulic oil.
• If the inner diameter of the clevis bushing is worn,
replace the bushing.

Rod Cover
• If the bushing inner diameter is worn and the
clearance with the piston rod is greater than 0.25
mm, replace the bushing.
• If the inside surface of the bushing is scratched, and
the scratches are deeper than the depth of the
coating layer, replace the bushing.

TB53FR IV-90
CYLINDERS HYDRAULIC UNITS
Inspection after Assembly
No Load Operation Test
1. Place the cylinder in a horizontal position with no
load.
2. Apply gentle pressure alternately to the ports at
both ends, operating the piston rod 5 or 6 times.
3. Make sure there is no abnormality in the operat-
ing condition.

Leak Test
External Leakage
1. Apply test pressure for 3 minutes each to the
retraction side and the extension side.
2. Make sure there are no abnormalities such as
external leakage or permanent deformation, etc.
in the rod seal, the rod cover mount, or in any
welded portion.

Internal Leakage
1. Disconnect the extension side hose.
2. Apply test pressure to the retraction side for 3
minutes.
3. Measure the amount of oil that has leaked from
the extension side.
• The amount of leakage should be 1 cm3 / 3min
or less.

Bleeding Air from the Hydraulic Cylinder

Bleed the air out of the cylinder when the cylinder is
removed or when the hydraulic piping, etc. is discon-
nected.
1. Start the engine and let it idle for approximately
5 minutes.
2. With the engine running at slow speed, extend
and retract the cylinder 4 or 5 times.
• Move the piston rod to a position 100 mm
before the end of the stroke, being careful not
to apply any relief at all.
3. With the engine at top speed, repeat the operation
in (2), then with the engine running at slow speed,
move the piston rod to the stroke end and apply
relief.

IV-91 TB53FR
HYDRAULIC UNITS CYLINDERS

TROUBLESHOOTING

Symptom Probable Causes Remedy

Oil leaks from piston rod • Foreign matter is caught in the inner • Remove the foreign matter.
sliding surface (an oil ring diameter portion of the rod packing,
forms on the piston and backup ring or dust seal.
this enlarges and drips off). • The inner diameter lip of the rod packing, • Replace the affected parts.
backup ring or dust seal is damaged or
abnormal.
• Piston rod sliding surface is scratched. • Smooth the sliding surface with an oil
stone (1.6 S or lower)
• If it leaks after the sliding surface has
been smoothed, replace the rod pack-
ing and other seals.
• If it leaks after the seals have been
replaced, replace the piston rod.
• The hardened chrome plating is separat- • Repair the hardened chrome plating.
ing from the piston rod.
Oil leaks from the outer • O-ring is damaged. • Replace the affected parts.
circumference of the rod • Backup ring is damaged. • Replace the affected parts.
cover.
Oil leaks from welded por- • The tube’s welds are damaged. • Replace the affected parts.
tion.
Cylinder natural drop (this • Foreign matter is caught in the wear ring • Remove the foreign matter.
is the maximum amount sliding surface.
of movement of the piston • The sliding surface of the wear ring is • Replace the affected parts.
in 10 minutes when a static scratched or abnormal.
weight corresponding to • The piston packing sliding surface is • Replace the affected parts.
the maximum use pressure scratched.
multiplied by the • The O-ring is damaged. • Replace the affected parts.
cylinder’s surface area) is
0.5 mm or greater.

TB53FR IV-92
CYLINDERS HYDRAULIC UNITS
TABLE OF SPECIAL TOOLS

Installation Jig (A) Installation Jig (B)

MATERIAL: SS41 MATERIAL: SS41

Unit: mm
Installation Jig (A) Installation Jig (B)
A B C D E F A B C D E F
Boom 64 60 42 12 51 60 74 59.5 10 5 30 80
Arm 54 50 32 12 46 50 59 49.8 10 5 30 64
Bucket 46.8 45 10 45 30 48.5 54 44.8 10 5 30 60
Dozer Blade 64 60 42 12 51 60 67 54.8 10 5 30 73
Offset 59 55 32 12 46 55 67 54.8 10 5 30 73

Sliding Jig (C) Fitting Jig (D)

MATERIAL: STKM13C MATERIAL: NYLON

Unit: mm
Sliding Jig (C) Fitting Jig (D)
A B C D E F A B C D E F
Boom 111.0 109.7 91 97.3 23.5 95 13 69 95 100 107 110
Arm 90.7 89.7 75 80.7 19.5 75 10 55 75 85 89 92
Bucket            
Dozer Blade 111.0 109.7 91 97.3 23.5 95 13 69 95 100 107 110
Offset 101.0 99.7 84 90.7 22.5 77 10 57 77 95 99 102

IV-93 TB53FR
HYDRAULIC UNITS CYLINDERS

Corrective Jig (E)

MATERIAL: STKM13C

Unit: mm
A B
Boom 123 110
Arm 103 90
Bucket  
Dozer Blade 123 110
Offset 113 100

TB53FR IV-94
TRAVEL MOTOR HYDRAULIC UNITS
TRAVEL MOTOR
CONSTRUCTION

Hydraulic Motor

1. Retainer 11. Pin 21. O-ring

2. Ball 12. Spring 22. O-ring
3. Shaft 13. Retainer 23. Backup Ring
4. Cylinder Block 14. Bearing 24. Friction Disc
5. Valve Plate 15. Bearing 25. Center Disc
6. Piston 16. 2-Speed Piston 26. Oil Seal
7. Shoe 17. Brake Piston 27. Spring Pin
8. Shoe Holder 18. Spring 28. Pin
9. Guide 19. Snap Ring 29. Backup Ring
10. Swash Plate 20. O-ring 30. Plug

IV-95 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

Reduction Gears

14 5 24 27 23 4 13 23 27 25 9 15 10

18

21

26

31

22

28

29

30

16 7 11 3 1 6 12 20 19 17

K3D501

1. Housing 9. Pin 17. Bearing 25. Pin

2. Cover 10. Flange Holder 18. Thrust Washer 26. Plug
3. Carrier 2 11. Snap Ring 19. Snap Ring 27. Thrust Washer
4. Gear B1 12. Carrier 1 20. Snap Ring 28. Plug
5. Gear B2 13. Needle 21. Snap Ring 29. O-ring
6. Gear S1 14. Needle 22. Ring 30. Snap Ring
7. Gear S2 15. Floating Seal 23. Ring 31. O-ring
8. Pin 16. O-ring 24. Pin

TB53FR IV-96
TRAVEL MOTOR HYDRAULIC UNITS
Counterbalance Valve, 2-speed Control Valve, Relief Block Assembly

      

       
     

  



     
 


1. Valve Body 12. Spool 23. Seat 34. O-ring

2. Spool 13. Spring 24. Spring Seat 35. O-ring
3. Check Valve 14. Plug 25. Spring 36. O-ring
4. Spring 15. O-ring 26. Plug 37. O-ring
5. Plug 16. Plug 27. O-ring 38. O-ring
6. O-ring 17. Plug 28. O-ring 39. O-ring
7. Spring Guide 18. Orifice 29. Backup Ring 40. Shuttle
8. Spring 19. Valve Body 30. Piston 41. Spacer
9. Cap 20. Relief Valve Assembly 31. O-ring
10. O-ring 21. Relief Housing 32. Stopper
11. Orifice 22. Poppet 33. Spacer

IV-97 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

OPERATION
    
Hydraulic Motor
9 pistons (2) are fitted in the cylinder block (1) and
there is a valve plate (3) with two half moon ports, B
and C in the end. Also, the cylinder block (1) rotates
freely and is joined to the shaft (4) via the spline. On
the other band, the swash plate (5) is fastened to the
housing.
When high pressure oil is introduced into port B, one
piston (2) makes contact and force F bears on the
swash plate (5).
F = P × A P: Pressure A: Piston Sectional Area
The force F which the piston (2) applies to the swash 
plate (5) is divided into force F1, which pushes the 
plate, and force F2, which rotates the cylinder block
(1). The total sum of the components in the direction
of rotation of the high pressure side piston generates
a rotational force in the cylinder block (1) and via the 
spline, torque is transmitted to the shaft (4), turning it.
Conversely, if high pressure oil is introduced to port
C, rotation is the reverse of the above. 


  


Counterbalance Valve
If high pressure oil is introduced to port P1, the oil
pushes the check valve (6) up. This causes oil to flow
through the motor port M1 and to flow into chamber
B of the pilot portion and fill it. When hydraulic oil
flows the motor from port M1 and acts to turn the
motor, even if oil returns from the motor and flows
into port M2, since the flow is cut off by the check
valve (6), the pressure at port P1 and in chamber B
rises. If the pressure in chamber B becomes higher
than the set valve of the spring (7), the spool (8) moves
to the left side and ports M2 and P2 open up, causing B C4D554
the motor to turn.

If the motor’s turning becomes too fast, and the B

amount of oil flowing out of port M2 is greater than
the amount of oil flowing into port M1, the pressure
D
in port P1 and chamber B drops. When the pressure in
chamber B drops below the set valve of the spring (7),
the spool (8) attempts to return to the right side. As a
result, since the resuming oil is constricted at portion
D, back pressure is generated at port M2 and the
motor’s turning is slowed.

C4D555

TB53FR IV-98
TRAVEL MOTOR HYDRAULIC UNITS
When the motor is slowed, the pressure in port P1 and
chamber B rises again and the spool (8) moves to the
left aide, eliminating the back pressure generated at
port M2. In this way, the motor is controlled so that it
rotates at a speed appropriate for the amount of oil
flowing into it.

If the high pressure hydraulic oil introduced into port B

P1 is cut off, the pressure at ports P1 and P2 becomes
the same and the spool (8) returns to the neutral
position by spring force. For this reason, the oil in
chamber B is pushed out at port P1. At this time, the
flow of oil is restricted by the orifice (9) as it is
returning to port P1, so the spool (8) returns to the
neutral position slowly. In this way, the motor is
stopped while the shock during stopping is absorbed.

C4D556

Relief Valve
Operation 1 M2 M1
When the Motor is Started
When the motor is started, since the inertial load is
great, the pressure of the oil required to accelerate it
rises. If this pressure reaches the relief valve set
pressure, the relief valve operates and oil returns to
port M2.
In this way, the motor begins to turn as it relieves the
relief valve, and as the rotational speed increases, the
amount of relief decreases until it stops.
In this way, the shock during starting is absorbed.
P2 P1 G4D503

When the Motor is Stopped

When the motor is stopped, the return circuit is closed M2 M1
off.
However, since the motor tends to want to continue
rotating due to inertial energy, the pressure in port M2
rises. When this pressure reaches the relief valve’s set
pressure, the relief valve operates and oil flows to port
M1. In this way, the flow of oil to port M1 prevents
cavitation from occurring as it absorbs the shock
during stopping.

P2 P1
G4D504

IV-99 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

Operation 2
Since this relief valve has a shockless mechanism, it
operates in 2 steps.
1st Step
When relief valve operation starts, the pressure in
chamber B (P1) is kept at a pressure which is lower
than that in chamber C while the pressure in chamber
A (P) becomes higher than the pressure of the oil
flowing in.
At this time, there are two forces acting on the poppet
(10), force (F), which attempts to move the poppet
(10) to the left and force (F1) which pushes against the
seat on the right side. Since F = P × A, F1 = P1 × A1,
P > P1 and A > A1, the poppet (10) is moved to the left
by this force “F-F1”.
This opens a supply side circuit from chamber A and
lets the pressure escape. That is, during the time piston
(11) is moving to its stroke end, the relief valve
operates at low pressure (about 1/3 the set pressure).

2nd Step
When the piston (11) reaches the stroke end, the
pressure in chamber B rises and the pressures in
chamber A and chamber B equalize. At this time, the
force moving the poppet (10) to the left side becomes
“P = P1”, so this becomes “A-A1” and the relief valve
operates at the specified set pressure.

2-Speed Mechanism
2-speed control valve
When high-pressure oil led to the port M1 and the
travel 2-speed solenoid valve (1) is set to speed 1, the
chamber C is connected to the tank via the travel 2-
speed solenoid (1), so that a low pressure is obtained.
For this reason, the spool (2) is pushed to the left by 4
the spring (4), the control chamber (3) and the tank
port (T) are connected, and there is no force pushing
the swash plate (5) in upward direction.

G4D507

When the travel 2-speed solenoid valve (1) is switched

to speed 2, the pressure oil from the travel 2-speed
solenoid valve (1) flows to the chamber C, the spool
(2) is moved to the right, and the port M1 is connected
with the port A, while the port M2 is connected with
the port B. Then the pressure oil from the port P1 4
moves the shuttle spool (12) to the right and flows to
the control chamber (3). This causes operation of the
control piston (11), and the swash plate (5) is pushed 12
up.
At the time of engine stop, no pressure oil is supplied
any longer, and the spring (4) returns the spool (2) to G4D508
the speed 1 position.

TB53FR IV-100
TRAVEL MOTOR HYDRAULIC UNITS
Swash Plate

8
β B

5 A
9
C α
11
3
10

E5D512

The swash plate (5) has 3 planes, A, B and C, as shown connected to the motor drive pressure port and the
in the figure, and it is assembled in such a way that its swash plate (5) stabilizes at plane B due to the equi-
angle of inclination in the flange holder (6) can varied librium between the force of the springs (9), (10) and
by two balls (7). When the 2-speed control valve is the force of the control piston (11), thus, assuming
switched to the 1st speed side, the swash plate control swash plate angle ß. In this way, 2nd speed (high
piston chamber is connected to tank port and the speed) motor rotation is achieved.
swash plate (5) is stabilized at plane A, forming swash When the engine is stopped, the pilot pressure of the
plate angle a, by the piston assembly (8) and the force 2-speed control valve is cut off, so the swash plate (5)
of the springs (9), (10), achieving 1st speed (low is stabilized at the swash plate a plane A by the force
speed) motor rotation. of the springs (9), (10), changing to the 1st speed side.
When the 2-speed control valve is switched to 2nd For this reason, when starting, the motor also is in 1st
speed, the swash plate control piston chamber (3) is speed.

Parking brake
The center discs (1) are connected to the flange holder
and the friction discs (2) are connected to the cylinder
block (3) via the spline, respectively. The center discs
(1) and friction discs (2) are pressed against the flange
holder (6) by the springs (4) via the brake piston (5).
The friction force between these discs generates the
brake torque to prevent the cylinder block (3) from
rotating.

When the pressure oil is introduced into the motor, the

spool of the counterbalance valve moves and the oil 3 6 2 1 5 4
C4D557
flows from the parking brake release port (7) into the
brake piston chamber (8). The oil pressure overpow-
ers the spring force and moves the brake piston (5) to
the right. This generates a clearance between the
center discs (1) and friction discs (2) to release the
parking brake. When the motor stops, the spool re-
turns to the neutral position to close the parking brake
release port (7). The pressure oil in the brake piston
chamber (8) is introduced into the motor case and the
spring (4) operates the parking brake.

2 1 8 7 5 4
C4D558

IV-101 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

Reduction Gears
The reduction gear has a simple planetary two-stage a1,a2
configuration. It decelerates the high speed rotary
motions of the hydraulic motor, converts them into
B1 B2
low speed high torque, and rotates the case. The
output shaft of the hydraulic motor is connected to the
gear S2 via the spline. The rotation of the gear S2 is
S1 1
decelerated by one stage among the gears S2, B2 and S2
a2. This one-stage decelerated rotation is further
decelerated by two stages among the gears S1, B1 and
a1 that are connected to the carrier 2 (1) via the spline.
This rotation is conveyed to the rotary main body via
the inner gears a1 and a2 as the driving force of the
motor. K3D502

TB53FR IV-102
TRAVEL MOTOR HYDRAULIC UNITS
DISASSEMBLY AND ASSEMBLY

General Cautions
• Carry out disassembly and assembly operations in • Replace all seals with new ones each time the unit
a clean place and provide clean containers to place is disassembled, coating them lightly with grease.
the disassembled parts in. • Check each part to make sure there is no abnormal
• Before disassembly, clean around the ports and wear or seizing and use sandpaper, etc. to remove
remove the paint from each joint using a wire any burrs, sharp edges, etc.
brush.
• Wash the disassembled parts and dry them with
compressed air. Do not use a rag, as this could
cause clogging of dirt.
• Make match marks on each part so that they will be
assembled in the same positions when reassembled.

The following describes the assembly procedure. For

disassembly, follow the procedure in the reverse
order referring to the construction diagram.

Assembly
Counterbalance Valve and Hydraulic Motor
1. Fix the body with a vise and mount the spool on
the body.
• To prevent the outer surface of the body from
being damaged, insert a protector such as an
aluminum plate between the body and the vise.
C4D561
• Do not disassemble the spool assembly into
parts.

2. Mount the rings (1) and springs (2) on both sides

of the spool.

1
2 C4D562

3. Fit the O-ring to the plug, and tighten the plug on

both sides of the body.
Plug: 196~245 N·m

C4D563

IV-103 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

4. Mount the second speed spool (4) and spring (5)

on the body.

4
5 C4D564

5. Fit the O-ring to the plug and tighten the plug to

the body.
Plug: 46~51 N·m

C4D565

6. Mount the shuttle on the body.

7. Fit the O-ring to the plug and tighten the plug to

the body.
Plug: 12~23 N·m

TB53FR IV-104
TRAVEL MOTOR HYDRAULIC UNITS
8. Mount the large and small O-rings on the flange
holder.

9. Press fit the oil seal into the flange holder.

• As the oil seal is to be inserted, do not disas-
semble it unless necessary.
• Fill between the lips of the oil seal with grease.

10. Fit the O-ring to the plug and install the plug on
the flange holder.
Plug: 12~13 N·m

K3D503

11. Mount the pin.

12. Mount the 2-speed piston.

G4D516

IV-105 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

13. Mount the shaft on the flange holder.

• The bearing has been inserted and cannot be
disassembled.
• Be careful not to damage the oil seal by the
shaft.

C4D567

14. Mount the balls and swash plate.

• Apply hydraulic oil to the sliding surfaces of
the swash plate.

C4D568

15. Mount the retainer (6), spring (8) and retainer (7)
on the cylinder block and fix them with the snap
ring (9).
9 7 6

8
K3D504

K3D505

16. Fit the three pins to the cylinder block.

17. Install the friction disc.

K3D506

TB53FR IV-106
TRAVEL MOTOR HYDRAULIC UNITS
18. Mount the piston (12) and guide (13) on to the
shoe holder (11) to assemble the shoe holder 11
assembly.
13

12

C4D572

19. Mount the shoe holder assembly on the cylinder

block to assemble the cylinder block assembly.

K3D507

20. Install the center disc in the groove of the flange

holder.

K3D508

21. Install the cylinder block assembly.

a. Install the shaft splinge in the guide.

K3D509

IV-107 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

22. Install the center disc in the groove of the flange

holder.

23. Mount two O-rings and two backup rings on the

brake piston.
• Be sure to position the backup rings on the
outer side.

C4D577

24. Mount the brake piston assembly on the flange

holder.
• Apply grease to the O-ring and be careful not
to let it bite the seal.

C4D578

25. Mount the valve plate on the flange holder and

insert the springs into the spring holes.
• The dot in the figure shows the spring installa-
tion positions.
• Assemble the valve plate in such a manner that
the copper surface is on the cylinder block side.
• Apply grease to the valve plate and springs,
and be careful not to drop them.

K3D511

TB53FR IV-108
TRAVEL MOTOR HYDRAULIC UNITS
26. Supply 200 mL of hydraulic oil into the flange
holder and mount the valve body on the flange
holder.

C4D581

27. Fix the flange holder with a vise and tighten it

with the screws.
Screw: 51~65 N·m
• Insert a protector such as an aluminum plate
between the flange holder and the vise to
prevent the outer surface of the body from
being damaged.

C4D582

28. Install the plug.

• Seal tape should be wound around the threads
of the plug.
Plug: 26~31 N·m

29. Mount the relief valve on the valve body.

Relief valve: 196~245 N·m

G4D518

IV-109 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

30. Mount the large and small O-ring on the body.

G4D519

31. Mount the relief valve on the motor and tighten

them with the cap screws.
Cap screw: 25~32 N·m

G4D520

Reduction Gears
1. Install the bearing (17), snap ring (18) and bear-
ing (17) in the housing.
• Be careful of the installation direction of the
bearings.

17 18 17

C4D583

C4D584

2. Fit the O-ring to the floating seal and install them

in the housing.
• Apply grease to the O-ring.

C4D585

TB53FR IV-110
TRAVEL MOTOR HYDRAULIC UNITS
3. Fit the O-ring to the floating seal and install them
in the flange holder.
• Apply grease to the O-ring.

K3D512

4. Mount the housing on the flange holder and fix

them with the snap ring.
• Tighten the housing of the reduction gear and
the flange of the hydraulic motor with a C-
clamp or hydraulic press, and fix them with the
snap ring.

K3D513

C4D588

5. Press fit the ring (1) to the gear B. 1 2

6. Install the needles (2) in the gear B.

• Apply grease to the needles to prevent from
coming off.

7. Press fit the ring (1) to the other end of the gear B.

K3D514

8. Install the thrust washer, the gear B assembly (3),

the thrust washer and the pin (4).

9. Press fit the spring pins to secure the pins (4).

3
4 K3D515

IV-111 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

10. Mount the gear S1 on the carrier and fix them with
the snap ring.

C4D590

11. Mount the thrust washer, gear B2, needle and

thrust washer on the carrier 2 and fix them with
the snap ring.

C4D591

12. Install the carrier 1 assembly in the housing.

K3D516

13. Install the thrust washer and the carrier 2 assem-

bly in the housing.

K3D517

TB53FR IV-112
TRAVEL MOTOR HYDRAULIC UNITS
14. Install the gear S2.

K3D518

15. Fit the O-ring to the housing.

16. Supply 0.8 L of lubricant.

C4D595

17. Install the ring on the cover.

• Apply grease to secure.

G4D524

18. Install the cover on the housing.

• Line up the plug holes (G 3/8) with the cuts in
the housing.

G4D525

IV-113 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

19. Fit the snap ring to secure the cover.

• Put the blade of a screwdriver on the snap ring
end and push it into position.

G4D526

20. Fit the O-rings to the plugs and install the plugs on
the cover.
Plug: 46~51 N·m

G4D527

21. Fit the O-ring to the plug and install the plug on
the cover.
Plug: 12~13 N·m

G4D528

TB53FR IV-114
TRAVEL MOTOR HYDRAULIC UNITS
INSPECTION AND ADJUSTMENT

Checking the Parts

Parts Area Checked Judgement Criteria Treatment
Floating Seal Sliding Surface There should be no abnormal scratches, Replace
wear or seizing.
Angular Bearing Sliding Surface There should be no abnormal scratches, Replace
wear, flaking, etc. in the ball or race.
Planetary Gears Surface of Gear Teeth There should be no abnormal scratches, Replace
wear or flaking of the tooth surfaces (if
there has been pitting which covers 5%
or more of the engagement portion of
the tooth surface).
Front of cage and roller ro- There should be no abnormal scratches,
tating surface. wear or flaking of the rotating surface.
Inner Race Surface condition of inner There should be no abnormal scratches, Replace
race rotating surface. wear or flaking of the rotating surface.
Needle Surface of needle. There should be no abnormal scratches, Replace
wear or flaking.
Thrust Washer Front of sliding surface There should be no abnormal scratches, Replace
wear or seizing.
Housing, Sun Gear, Front of Gear Tooth Sur- There should be no abnormal scratches, Replace
Drive Gear faces wear or flaking in the tooth surfaces (if
there has been pitting which covers 5%
or more of the engagement portion of
the tooth surface).
Thrust Plate Front of sliding surface. There should be no abnormal scratches Replace
(0.02 mm or greater), wear or seizing,
etc.
O-ring   Replace
Shaft Surface of oil seal. There should be no scratches or abnor- Replace
mal wear.
Ball Bearing Front of sliding surface. There should be no abnormal scratches, Replace
wear or flaking in the ball and race.
Oil Seal   Replace
Swash Plate Front of the surface which There should be no abnormal scratches Repair by lapping
slides with the sliding sur- (0.02 mm or greater), wear or seizing. (#1000) or replace.
face of the piston assembly.
Cylinder Block Clearance with the piston 0.04 mm or greater Repair with wrap
assembly. (#1000) or replace
Front of the surface which There should be no abnormal scratches the cylinder block
slides with the valve plate. (0.02 mm or greater), wear or seizing. and piston assem-
bly at the same
Piston Assembly Clearance with cylinder 0.04 mm or greater
time.
block
Front of the surface which There should be no abnormal scratches
slides with the swash plate. (0.02 mm or greater), wear or seizing.
Clearance between piston 0.4 mm or greater Replace
and shoe.

IV-115 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

Parts Area Checked Judgement Criteria Treatment

Valve Plate Front of the surface which There should be no abnormal scratches Repair by lapping
slides with the spool. (0.02 mm or greater), wear or seizing. (#1000) or replace.
Base Plate Front of the surface which There should be no abnormal scratches, Replace the base
slides with the spool. wear or seizing. plate and the spool
Spool Front of the surface which There should be no abnormal scratches, at the same time.
slides with the base plate. wear or seizing.
Front of the surface which There should be no abnormal scratches, Replace the spool
slides with the check valve. wear or seizing. and the check
Check Valve Front of the surface which There should be no abnormal scratches, valve at the same
slides with the spool. wear or seizing. time.
Surface of spool and seat. There should be contact with the seat
around the entire circumference.

TB53FR IV-116
TRAVEL MOTOR HYDRAULIC UNITS
TROUBLESHOOTING

Hydraulic Motor
Symptom Probable Causes Remedy
Does not move. • Equipment other than the motor, coun- • Check if the proper pressure is reached
terbalance valve or speed reducer is on the motor inlet port side, then check
malfunctioning. each device and repair if necessary.
• Hydraulic oil is escaping due to ab- • Replace the abnormally worn parts.
normal wear of motor sliding parts.
• Principal motor parts are malfunc- • Replace the damaged parts.
tioning due to damage.
Motor won’t speed up. • The proper volume of hydraulic oil is • Check if the proper pressure is reached
not being supplied to the motor due to on the motor inlet port side, then check
the hydraulic pump, control valve, each device and repair if necessary.
etc.
• The motor’s volumetric efficiency is
• Check if the sliding parts are abnor-
dropping. mally worn, then repair or replace the
worn parts.
Changes in rotational speed • High pressure hydraulic oil is leaking • Replace the abnormally worn parts.
are great. and flowing out of the drain port due
to wear of the motor's sliding parts.
• Bearings are worn. • Replace the bearings if they are abnor-
mally worn.
Oil is leaking. • Oil is leaking due damage to oil seals • Replace the oil seals and O-rings.
or O-rings.

Counterbalance Valve
Symptom Probable Causes Remedy
Does not move or rotation is Spool does not switch.
slow. • No hydraulic oil is arriving. • Repair or replace the damaged piping.
• Foreign matter is caught. • Remove the foreign matter and repair
or replace the damaged parts.
• The orifice is clogged up. • Clean it.
Won’t stop or stopping is The spool won’t return.
slow. • Foreign matter gets caught. • Remove the foreign matter and repair
or replace the damaged parts.
• A spring is missing. • Install the spring.
• A spring is damaged. • Replace the spring.
• The orifice is clogged up. • Clean it.
Shock is great when stopping. Spool return is fast.
• The spring seat is missing. • Install the spring seat.
Valve makes an abnormal The spool does not return.
noise. • Foreign matter gets caught. • Remove the foreign matter and repair
or replace the damaged parts.
• A spring is damaged. • Replace the spring.
• The orifice is clogged up. • Clean it.

IV-117 TB53FR
HYDRAULIC UNITS TRAVEL MOTOR

2-speed Control Function

Symptom Probable Causes Remedy
Machine veers during travel. Spool doesn’t switch over.
• Foreign matter is caught. • Remove the foreign matter and repair
or replace the damaged parts.
• A spring is missing. • Install the spring.
• A spring is damaged. • Replace the spring.

TB53FR IV-118
SLEW MOTOR HYDRAULIC UNITS
SLEW MOTOR
CONSTRUCTION

Hydraulic Motor

26 1 7 2 4 18 6 27 19 25

15
24

17
12

8
10
27
20

11 14 5 22 23 13 9 21 16

K3D600

1. O-ring 10. Retainer 19. Shoe Holder

2. O-ring 11. Spring 20. Pin
3. O-ring 12. Retainer 21. O-ring
4. O-ring 13. Guide 22. Center Disc
5. Friction Disc 14. Pin 23. Swash Plate
6. Cylinder Block 15. Valve Plate 24. Bearing
7. Brake Piston 16. Bearing 25. Housing
8. Spring 17. Snap Ring 26. Pin
9. Shaft 18. Collar 27. Piston

IV-119 TB53FR
HYDRAULIC UNITS SLEW MOTOR

Reduction Gears

22 26 25 24 23 21 27 20 11 17 9 2 18 1 8 4 3

16 19 15 14 13 12 10 7 28 5 6

K3D601

1. Plate 11. Ring Gear 21. Carrier 1

2. Oil Seal 12. Race 22. Pin
3. Shaft 13. Needle 23. Race
4. Collar 14. Planetary Gear 24. Needle
5. Bearing 15. Thrust Plate 25. Planetary Gear A
6. Housing 16. Drive Gear 26. Thrust Plate
7. Bearing 17. O-ring 27. Snap Ring
8. Plate 18. O-ring 28. Collar
9. Nut 19. Screw
10. Carrier 2 20. Sun Gear

TB53FR IV-120
SLEW MOTOR HYDRAULIC UNITS
Brake Valve

27 26 28 25
10 12 16 22 15 38 19 18
11

14 30 D
7
17 2 37 6 13 4 36 1 9 3 5
29 30

A 32
B
31
20
35

34

33
32

32

39

C 41 40 8
42 43 44 46

45 23 24 21 K3D602
A: Relief Valve
B: Timer Valve
C: Check Valve
D: Anti-rebound Valve

1. O-ring 13. Spring 25. Body 37. Backup ring

2. Poppet 14. Plug 26. Check Valve Assembly 38. Backup ring
3. O-ring 15. Piston 27. Spring 39. Cover
4. O-ring 16. Spring 28. Sleeve 40. Spring
5. Backup ring 17. O-ring 29. Orifice 41. Poppet
6. O-ring 18. Guide 30. O-ring 42. Body
7. O-ring 19. O-ring 31. Body 43. Valve
8. O-ring 20. O-ring 32. O-ring 44. Filter
9. Backup ring 21. O-ring 33. Filter 45. Orifice
10. Sleeve 22. Guide 34. Washer 46. Orifice
11. Seat 23. Washer 35. Orifice
12. Seat 24. Spring 36. Backup ring

IV-121 TB53FR
HYDRAULIC UNITS SLEW MOTOR

OPERATION
3 2 1
Hydraulic Motor
9 pistons (2) are fitted in the cylinder block (1) and
there is a valve plate (3) with two half moon ports, B
and C in the end. Also, the cylinder block (1) rotates
freely and is joined to the shaft (4) via the spline. On
the other band, the swash plate (5) is fastened to the
housing. A
When high pressure oil is introduced into port B, one
piston (2) makes contact and force F bears on the
swash plate (5).
F = P × A P: Pressure A: Piston Sectional Area
The force F which the piston (2) applies to the swash
plate (5) is divided into force F1, which pushes the F1
plate, and force F2, which rotates the cylinder block F2 5 4
F
(1). The total sum of the components in the direction
of rotation of the high pressure side piston generates
F
a rotational force in the cylinder block (1) and via the
F2
spline, torque is transmitted to the shaft (4), turning it.
Conversely, if high pressure oil is introduced to port F
C, rotation is the reverse of the above.
F2

F
F2
B C
VIEW A E5D603

Relief Valve M2 M1
Operation 1
When the Motor is Started
When the motor is started, since the inertial load is
great, the pressure of the oil required to accelerate it
rises. If this pressure reaches the relief valve set
pressure, the relief valve operates and oil returns to
port M2.
In this way, the motor begins to turn as it relieves the
relief valve, and as the rotational speed increases, the
amount of relief decreases until it stops.
In this way, the shock during starting is absorbed. T
E5D605

When the Motor is Stopped M2 M1

When the motor is stopped, the return circuit is closed
off.
However, since the motor tends to want to continue
rotating due to inertial energy, the pressure in port M2
rises. When this pressure reaches the relief valve’s set
pressure, the relief valve operates and oil flows to port
M1. In this way, the flow of oil to port M1 prevents
cavitation from occurring as it absorbs the shock
during stopping.
T
E5D606

TB53FR IV-122
SLEW MOTOR HYDRAULIC UNITS
Operation 2
Since this relief valve has a shockless mechanism, it


operates in 2 steps.
1st Step
When relief valve operation starts, the pressure in
chamber B (P1) is kept at a pressure which is lower
than that in chamber C while the pressure in chamber  
A (P) becomes higher than the pressure of the oil
flowing in.
At this time, there are two forces acting on the poppet
(10), force (F), which attempts to move the poppet
(10) to the left and force (F1) which pushes against the
seat on the right side. Since F = P × A, F1 = P1 × A1,  
 
P > P1 and A > A1, the poppet (10) is moved to the left
by this force “F-F1”.
This opens a supply side circuit from chamber A and 10 A
lets the pressure escape. That is, during the time piston
(11) is moving to its stroke end, the relief valve
operates at low pressure (about 1/3 the set pressure).

2nd Step
P1 P
When the piston (11) reaches the stroke end, the
pressure in chamber B rises and the pressures in
chamber A and chamber B equalize. At this time, the
force moving the poppet (10) to the left side becomes
“P = P1”, so this becomes “A-A1” and the relief valve
operates at the specified set pressure. B 11
E5D636

Anti-rebound Valve 2 B
When the motor stops, this valve will connect the
motor main circuit to the makeup circuit for a pre-
scribed time to prevent motor rebound due to the
pressure in the main circuit.

When the Brake is Actuated

The braking pressure generated at the port Pv1 will
move the check valve (2) to the right until it is seated
at section B. Pv1 Cv Pv2

G4D604

When the Motor Rebounds

When the motor is stopped by braking operation of the
brake valve, it starts to rebound due to the pressure in
the main circuit. This rebound pressure generated at
the port Pv2 will move the sleeve (3) to the left to open
the passage. This then releases the rebound pressure
to the port Cv.

Pv1 Cv Pv2

B 3
G4D605

IV-123 TB53FR
HYDRAULIC UNITS SLEW MOTOR

The rebound pressure also pushes the check valve (1)

to the left, which is the opposite direction of pushing 2 1
at the time of braking. The flux control valve built in
the check valve (2) (that is now on the lower pressure
side) releases the oil in the damper chamber (4) at a
constant flux. Therefore, the check valve (1) moves at
a constant speed. When the check valve reaches its
stroke end, the passage from the port Pv2 to the port
Cv is closed.

Pv1 Cv Pv2

4
G4D606

Timer Valve 2 1 PG
This function is used to prevent sudden operation of
the parking brake when the motor is stopped.
At the time of parking brake operation, pressure oil
from the port P4 is supplied at all times to the port PG, SH
the valve spool (1) is pushed to the right by the force
of the spring (2), and the port PG is closed. PB
When turning pilot pressure or arm pilot pressure is
led to the port SH, the spool (1) is moved to the left
against the force of the spring (2), and the port PG is
opened. The pressure oil from the port PG passes
through the hole at the center of the spool (1) and is led
to the parking brake release port (PB), so that the K3D607

parking brake is released.

2 1 PG
When the pilot pressure at the port SH disappears, the
spool (1) is moved by the force of the spring (2) to the
right, the port PG is closed, and the oil in the brake
piston chamber (3) is prevented from escaping. The
oil in the chamber flows gradually through the ori-
fices (4), (5) in the spool (1) to the drain port dr, so that
the parking brake is not applied rapidly, but after a 5
certain time, just as if a timer were used. 4

3 K3D608

TB53FR IV-124
SLEW MOTOR HYDRAULIC UNITS
Parking Brake
The center discs (1) are connected to the housing and
the friction discs (2) are connected to the cylinder
block (3) via the spline, respectively. The center discs
(1) and friction discs (2) are pressed against the
housing (6) by the springs (4) via the brake piston (5).
The friction force between these discs generates the
6
brake torque to prevent the cylinder block (3) from
5
rotating. 2
4

1 3

K3D605

When the pressure oil is introduced into the motor, the

oil flows from the parking brake release port (7) into
the brake piston chamber (8). The oil pressure over-
powers the spring force and moves the brake piston
(5) to the right. This generates a clearance between the
center discs (1) and friction discs (2) to release the 7 8
parking brake. When the motor stops, the spool re- 2
turns to the neutral position to close the parking brake 5
release port (7). The pressure oil in the brake piston 1
chamber (8) is introduced into the motor case and the 4
spring (4) operates the parking brake.
K3D606

Reduction Gears
The reduction gear is composed of a 2-stage planetary
gear mechanism, and it converts the high-speed op-
eration of the motor to low speed torque for operation
of the pinion shaft (1).
In the figure on the right, the drive force transmitted
from the motor output shaft is transmitted to the
second stage sun gear (5) via the first stage drive gear
(2), the planetary gear (3) and the carrier 1 (4). Drive
force is transmitted in the same way to the pinion shaft
(1) via the second stage sun gear (5), the planetary
gear (6), and the carrier 2 (7), and this becomes the
slewing drive force.

IV-125 TB53FR
HYDRAULIC UNITS SLEW MOTOR

DISASSEMBLY AND ASSEMBLY

Table of Special Tools

Unit: mm
NAME, DIMENSIONS NAME, DIMENSIONS
JIG (A) JIG (F)

1 6

JIG (B) JIG (G)

2 7

JIG (C) JIG (H)

3 8

JIG (D) JIG ( I )

4 9

JIG (E) JIG (J)

5 10

TB53FR IV-126
SLEW MOTOR HYDRAULIC UNITS
Unit: mm
NAME, DIMENSIONS NAME, DIMENSIONS
JIG (K) JIG (O)

11

15

JIG (L)

JIG (P)
12

16
JIG (M)

13

JIG (Q)

JIG (N)

17
14

A: Adjust the internal gear so that a Gear type Profile shifted gear Diameter of standard pitch circle ø 91.000
clearance of 0.3 to 0.5 mm is
produced when the male gear Tooth Standard gear tooth Amount of addendum modification 1.95
(shown in the table) is inserted.
Module 6.5 Height of tooth 14.625
B: Width across flat
Pressure angle 20° Addendum circle diameter ø 107.9
No. of teeth 14 Dedendum circle diameter ø 78.65

IV-127 TB53FR
HYDRAULIC UNITS SLEW MOTOR

General Cautions
• Carry out disassembly and assembly operations in • Check each part to make sure there is no abnormal
a clean place and provide clean containers to place wear or seizing and use sandpaper, etc. to remove
the disassembled parts in. any burrs, sharp edges, etc.
• Before disassembly, clean around the ports and
remove the paint from each joint using a wire
brush.
• Wash the disassembled parts and dry them with
compressed air. Do not use a rag, as this could
cause clogging of dirt.
• Make match marks on each part so that they will be
assembled in the same positions when reassembled.
• Replace all seals with new ones each time the unit
is disassembled, coating them lightly with grease.

Disassembly
Slew Motor
1. Remove the cap screws and then the anti-rebound
valve.

K3D626

2. Remove the cap screws to disassemble the motor

into the hydraulic motor (1) and the reduction
gear (2). 1
• Mark the mating position on both the hydraulic
motor and the reduction gear so that they can
be mated correctly when reassembling.
2
• Fix the hydraulic motor with a vise.

K3D627

Brake Valve and Hydraulic Motor 1

1. Remove the cap screws and then the timer valve
(1).
• Be careful not to miss the O-ring.

K3D628

TB53FR IV-128
SLEW MOTOR HYDRAULIC UNITS
2. Remove the cap screws and then the cover (2).
• Fix the hydraulic motor with a vise.
• Be careful not to let the valve plate drop off. 2

K3D629

3. Remove the valve plate (3) from the cover.

3

K3D630

4. Remove the bearing (4). 4

K3D631

5. Remove the orifice (5).

• The orifice is caulked. Do not remove it unless 5
necessary.

K3D632

IV-129 TB53FR
HYDRAULIC UNITS SLEW MOTOR

6. Remove the check valve.

a. Remove the plug (6).
b. Remove the spring (7) and check valve (8).

8
7
6

K3D633

7. Remove the relief valve.

a. Remove the plug (9) and piston (10). 15 10 9
• Do not loosen the set screw nut (11).

11

K3D634

b. Remove the springs (12) and (13) and piston 14 12 13

guide (14).
• Use a pair of tweezers.
• Be careful not to damage the piston guide.

K3D635

c. Remove the relief housing (15). 15

• Pinch section A with a pair of pliers.
• Be careful not to damage the pinched sec-
tion.

A K3D637

K3D636

TB53FR IV-130
SLEW MOTOR HYDRAULIC UNITS
8. Remove the brake piston (16).
• Blow the air from the brake release port PB 16
with care such that the brake piston does not
protrude.
PB

K3D638

9. Remove the collar (17).

• Use the jig (B). 17

K3D639

10. Remove the cylinder block (18), friction discs 18

19
(19) and center discs (20).
20
19
20
19
20

K3D640

11. Remove the shoe holder (20) and piston assembly 20 21 22 23

(21) from the cylinder block.

12. Remove the guide (22) and pins (23) from the
cylinder block.

E5D621

IV-131 TB53FR
HYDRAULIC UNITS SLEW MOTOR

13. Remove the snap ring (24), retainer (25), spring

(26) and retainer (27) from the cylinder block 24
(18). 25
• To remove the snap ring, push up the retainer 26
(25) by using the press and jig (C). 27
18

A
E5D622

14. Remove the swash plate (28).

• Use the jig (B). 28

A
K3D641

15. Remove the shaft (29). 29

• Lightly tap the end face with a plastic hammer.

K3D642

16. Remove the bearing (30) from the shaft (29).

• Use the press and jig (D). 29

30

K3D643

TB53FR IV-132
SLEW MOTOR HYDRAULIC UNITS
17. Disassemble the timer valve.
• Be careful not to damage or deform the contact 31
surface. 32
a. Remove the plug (31). 33
b. Remove the spring (32) and valve (33).
• Use a pair of tweezers.

K3D644

c. Remove the orifice (34) from the valve (33). 34

• Adhesive has been applied to the orifice.
A

33

K3D645

d. Remove the washer (35), orifice (36) and filter 36

(37) from the valve (33).
37

33

35

36

35
K3D646

Reduction Gears 1
1. Remove the ring gear (1).

K3D647

IV-133 TB53FR
HYDRAULIC UNITS SLEW MOTOR

2. Remove the thrust plate (2).

2
3. Remove the drive gear (3). 3

K3D648

4. Remove the planetary gear A (4), needles (5) and 4 5

6
inner race (6).
7
5. Remove the carrier 1 (7).

K3D649

6. Remove the snap ring (8) and then the sun gear 9 8
(9).
10
7. Remove the carrier 2 assembly (10).

K3D650

8. Loosen the screw and remove the thrust plate

(11).
• Loctite has been applied to the screw. Warm-
ing the screw screws (for example, using a 11 14 13 12
portable drier) will make its removal much
easier.

9. Remove the planetary gear B (12), needle (13)

and inner race (14).

K3D651

TB53FR IV-134
SLEW MOTOR HYDRAULIC UNITS
10. Remove the U nut (15).
• Do not remove the U nut unless the taper roller
bearing (16) or (17) and/or collar (18) is faulty.
If one of them is faulty, the whole U nut should 15
be replaced.
• Use the jig (P) to fix the shaft. 16
• The U nut should be replaced with a new one
every time it is disassembled. 18

17

P
K3D652

11. Insert the jigs (N) and (Q) in the pinion section of
the shaft (19) to hold down the collar (20).
• Do not remove the shaft unless necessary. 19 E

21
12. Put the jig (E) on the upper part of the shaft and
pull out the shaft by using the press.
22
• The plates (21) and (22) should be replaced
with new ones every time they are disassembled. 20
Q

K3D653

13. Remove the oil seal (23).

• Use a flat blade screwdriver.
• The oil seal should be replaced with a new one
23
every time it is disassembled.
• Be careful not to damage the outer race of the
taper roller bearing. A

K3D654

14. Remove the outer race (24) of the taper roller

A
bearing.
• Use the pulley remover (for pulleys of ø85 mm
in diameter) and jig (A).

24

K3D655

IV-135 TB53FR
HYDRAULIC UNITS SLEW MOTOR

15. Remove the plug (25) from the case.

25

K3D656

Assembly 36
Brake Valve and Hydraulic Motor
37
1. Assemble the timer valve.
• Be careful not to damage the rotation section of 33
the valve.
a. Mount the filter (37), washer (36) and orifice 35
(35) on the valve (33).
• Position the hole of the orifice (35) as shown 36
in the figure.

35
K3D646

b. Mount the orifice (34) on the valve (33). 34

• Apply adhesive to section A of the orifice in
advance. Excessive application may clog A
the hole.
Orifice: 4.9 ±1.0 N·m

33

K3D645

TB53FR IV-136
SLEW MOTOR HYDRAULIC UNITS
c. Mount the valve (33) and spring (32) on the
body. 31
d. Fit the O-ring to the plug (31) and mount them 32
on the body. 33
Plug: 39.2 ±2.0 N·m

K3D644

2. Mount the retainer (27), spring (26), retainer (25) 24

and snap ring (24) on the cylinder block (18). 25
• To mount the snap ring, push the retainer (25) 26
by using the press and jig (C). 27
• Position the retainer (27) so that its tapered 18
side (A) faces the cylinder block.

A
E5D622

3. Fit the pins (23) to the cylinder block. 20 21 22 23

• Apply grease to the pins.

4. Mount the guide (22).

5. Fit the shoe holder (20) to the piston assembly

(21) and mount them on the cylinder block.
• Apply the hydraulic oil to the rotation section.

E5D621

6. Insert the bearing (30) into the shaft (29).

• Insert the bearing by using the press and jig (F). 29

30

K3D643

IV-137 TB53FR
HYDRAULIC UNITS SLEW MOTOR

7. Install the shaft (29) in the housing.

• Lightly tap with a plastic hammer to install.

29
K3D657

8. Install the switch plate (28) in the housing.

• Apply grease to the side (A) of the swash plate. 28

A
K3D641

9. Install the cylinder block (18) in the housing. 18

19
• Be careful not to let the shoe holder or other
parts drop off. 20
19
10. Mount three center discs (20) and three friction 20
19
discs (19). 20
• Total number of friction discs: 3
• Total number of center discs: 3
• Be careful of the mounting order.

K3D640

11. Fit the O-ring to the collar (17) and insert them in
the housing. 17
• Use the jig (G) and the press to insert.

K3D639

TB53FR IV-138
SLEW MOTOR HYDRAULIC UNITS
12. Fit the O-ring to the brake piston (15) and insert
them in the housing. B
• Use the jig (G) and the press to insert.
• The screw M6 position (A) should be as shown
in the figure. 15
• Insertion depth (B) should be 0 to 1 mm.

K3D658

13. Mount the springs (16) and O-ring (17). 17 16

K3D659

14. Assemble the relief valve assembly. 10 9

a. Fit the O-ring and backup ring to the piston
(10).
b. Fit the backup ring and O-ring to the plug (9).

K3D660

c. Fit the backup ring and O-ring to the relief 15 14 12 13

housing (15).
d. Install the spring sheet (38) and spring (13) in
the relief housing (15).
• Be careful of the mounting direction of the
spring sheet (38).
e. Install the guide (14) in the relief housing (15).
f. Mount the spring (12) on the guide(14).

38

K3D661

IV-139 TB53FR
HYDRAULIC UNITS SLEW MOTOR

g. Unite the relief housing (15), plug (9) and

piston (10).
h. Mount the relief valve assembly on the cover. 15 10 9
• Be careful not to let the spring jump out.
Plug: 275 ±10 N·m
• Do not loosen the lock nut (11).

11

K3D634

15. Mount the check valve.

a. Mount the spring (7) and poppet (8) on the
cover.
b. Fit the O-ring to the plug (6) and mount them
on the cover.
8
Plug: 157 ±10 N·m 7
6

K3D633

16. Insert the bearing (4) into the cover. 4

• Use the jig (H) and the press to insert.

K3D631

17. Fit the pin (39) to the cover. 39

• Caulk the pin at two positions by using a
punch. Protrusion due to caulking should not
be more than 1 mm.

39

K3D663

K3D662

TB53FR IV-140
SLEW MOTOR HYDRAULIC UNITS
18. Mount the orifice (5) on the cover.
• Caulk the circumference of the orifice female
screw by using a punch. 5
Orifice: 2.45 ±0.49 N·m

K3D632

19. Mount the pin and valve plate (3) on the cover.
• Apply grease on the back of the valve plate (the 3
side facing the cover) in advance to prevent the
plate from dropping off. 3

K3D630

20. Mount the cover (2) on the case and fix them with
the cap screws. 2
• Be careful not to let the valve plate drop off.
Cap screw: 128 ±7 N·m

K3D629

21. Mount the timer valve (1). 1

a. Fit the O-ring to the case.
b. Mount the timer valve and fix it with the screw.
Screw: 10 ±1 N·m

K3D628

IV-141 TB53FR
HYDRAULIC UNITS SLEW MOTOR

Reduction Gears
1. Mount the collar (20) and plates (21) and (22) on
the shaft (19).
• Apply grease to the case side of the plate (22). I
• The plates (21) and (22) should be new ones.

2. Insert the inner race (26) of the taper roller bear- 26

ing into the shaft.
• Use the jig (I) and the press to insert.
21

22
20 19
K3D664

3. Fit the O-ring to the shaft and mount the collar

(18).
• Be careful of the mounting direction of the
collar (18).
• Use the jig (I) and the press to mount.

4. Insert the oil seal (23) into the case.

• Use the jig (K) and the press to insert.
• The oil seal diameter (A) after insertion should
23
be 4.25 mm.

K3D654

5. Insert the outer race (24) of the taper roller bear-

ing into the case.
• Use the jig (L) and the press to insert.

TB53FR IV-142
SLEW MOTOR HYDRAULIC UNITS
6. Put grease into the inner race of the taper roller
bearing.
• Grease type: Shell ALVANIA Grease
• Grease volume: 62~72 mL

E5D629

7. Mount the shaft (19) and plug (25) on the case.

• The shaft (19) should be mounted before mount-
ing the plug (25).

8. Mount the inner race (27) of the taper roller

bearing to the shaft.
• Use the jig (M) and the press to mount.

9. Mount the U nut (15).

• Be careful of the mounting direction of the U
nut. 15
• Fix the shaft with the jig (P) and tighten it with
the jig (O). 16
• Be sure to use a new U nut.
U nut: 933 ±49 N·m 18

17

P
K3D652

IV-143 TB53FR
HYDRAULIC UNITS SLEW MOTOR

10. Fit the O-ring to the case and mount the ring gear
(1).
• Align the positions of the M12 hole of the case
and the hole (ø13 mm in diameter) of the ring
gear.

11. Mount the inner race (14), needles (13) and plan-
etary gear B (12) on the carrier 2.
• Be careful of the mounting direction of the
planetary gear B. 11 14 13 12

12. Mount the thrust plate (11) and fix it with the cap
screws.
• Apply Loctite #242 to the cap screws in ad-
vance.
Cap screw: 6.1 ±2.0 N·m

K3D651

13. Mount the carrier 2 (10) on the case.

14. Fit the snap ring (8) to the sun gear (9) and mount
them.

15. Fit the spring pin to the carrier 1.

• Let the slit section of the spring face outside as
shown in the figure.

TB53FR IV-144
SLEW MOTOR HYDRAULIC UNITS
16. Mount the carrier 1 (7).

17. Mount the inner race (5), needles (6) and plan-
etary gear A (4) on the carrier 1 (7).
• Mount the planetary gear A as shown in the
figure.

18. Mount the drive gear (3).

19. Mount the thrust plate (2).

• Measure the depth (A) from the case end to the
carrier 1 and select a proper thickness for the
thrust plate by referring to the table.
• The largely-rounded side of the thrust plate
circumference should face the planetary gear.

From 14.0 to less

Depth (A) Less than 14.0 mm 14.5 mm or more
than 14.5 mm
Thrust plate
1.8 mm 2.3 mm 2.8 mm
thickness

Slew Motor
1. Unite the hydraulic motor (1) and the reduction
gear (2) and fix them with the cap screws. 1
Cap screw: 128 ±7 N·m

K3D627

IV-145 TB53FR
HYDRAULIC UNITS SLEW MOTOR

2. Fit the O-ring to the cover.

3. Fit the anti-rebound valve to the cover and mount

the washer, seal and screws.
Screw: 29.4 ±2 N·m

K3D626

TB53FR IV-146
SLEW MOTOR HYDRAULIC UNITS
INSPECTION AND ADJUSTMENT

Checking the Parts

Brake Valve
Parts Judgement Criteria Treatment
Check Valve, • Scratches in sliding portions are deep or roughness is severe. • Replace
Piston • The clearance with the body is large. • Replace
• Scratches in sliding portions are deep or seating is uneven. • Replace
Housing • Scratches in sliding portions are deep or roughness is severe. • Replace
• There are scratches where oil leakage occurs. • Replace
Relief Valve • The set pressure drops abnormally low. • Replace
Assembly • The set pressure is unstable and vibration occurs. • Replace
• There is a lot of leakage due to faulty seating, etc. • Replace
Spring • Damaged or severely deformed. • Replace

Hydraulic Motor
Recommended
Standard
Parts Replacement Treatment
Dimension
Value
Clearance (S) be- Replace cylinder
tween piston and block, swash plate
D
d

cylinder bore assembly.

0.02 mm 0.04 mm

S=D-d
E5D632

Clearance (S) be- Replace cylinder

tween piston and block, swash plate
shoe assembly.
0.15 mm 0.4 mm
S
E5D633

Shaft and needle Flaking or pitting Replace shaft, port

bearing rolling sur- in the rolling sur- block assembly.
face face.

E5D634

Cylinder block Sliding surface is Carry out lap re-

sliding surface (1) 1 rough. pairs (#1000 Pow-
der) or replace.
Valve plate sliding Replace
surface (2) 2
E5D635

IV-147 TB53FR
HYDRAULIC UNITS SLEW MOTOR

Reduction Gears
Parts Judgement Criteria Treatment
Drive Gear • Gear tooth surfaces are pitted or separating, etc. • Replace
• Clearance with motor joint is large due to spline wear. • Replace
Housing, • Gear tooth surfaces are pitted or separating, etc. • Replace
Internal Gear
Planetary Gear • Gear tooth surfaces are pitted or separating, etc. • Replace
• Needle rolling surfaces are pitted or separating, etc. • Replace
Needle Bearing, • Needle and shaft rolling surfaces are pitted or separating, etc. • Replace
Planetary Shaft • Pressure marks, etc. on needle and shaft rolling surfaces. • Replace
• Bearing rotation is abnormal (abnormal noise, rotation not smooth, • Replace
etc.).
Carrier, Shaft • Clearance with planetary shaft is large. • Replace
Shaft • Clearance with pinion is large due to spline wear. • Replace
Thrust Wasyer • Amount of wear is great. • Replace
Ball Bearing, • Rotation is abnormal (abnormal noise, rotation not smooth, etc.). • Replace
Roller Bearing • Flaking, separation, etc. on rolling surfaces. • Replace
• Pressure marks, etc. on rolling surfaces. • Replace
Collar, Oil Seal, • Scratches, etc. exist which cause leaks. • Replace
O-ring

Anti-rebound Valve
Parts Judgement Criteria Treatment
Check Valve • Scratches in sliding portions are deep or roughness is severe. • Replace
• The clearance with the body is large. • Replace
• Scratches in sliding portions are deep or seating is uneven. • Replace
Body • Scratches in sliding portions are deep or roughness is severe. • Replace
• There are scratches where oil leakage occurs. • Replace
Spring, Sleeve • Damaged or severely deformed. • Replace

Brake Valve
Adjusting the Relief Valve Pressure
“II, Specifications, Performance Judgment Stan-
dards”

TB53FR IV-148
SLEW MOTOR HYDRAULIC UNITS
TROUBLESHOOTING

If there is an abnormal increase in noise or heat, this The following table shows a number of causes of
is an indication that trouble has occurred. When this general breakdowns that can be seen in the hydraulic
type of condition is manifested, stop the machine circuits and indicates coutermeasures to take in each
immediately and search out the source of the trouble. case.

Symptom How/Where? Probable Causes Remedy

Motor does not start. Pressure doesn’t rise at the • Relief valve’s set pressure • Set the pressure at the cor-
motor’s inlet port. is low. rect level.
• Pump is broken down. • Repair or replace the
pump.
• Control valve is broken • Repair or replace the con-
down. trol valve.
Pressure rises at the motor’s • The load is excessive. • Lighten the load.
inlet port. • Hydraulic motor is broken • Repair or replace the hy-
down. draulic motor.
• Reduction gears are bro- • Repair or replace the re-
ken down. duction gears.
Motor’s speed won’t • Pump’s discharge vol- • Pump’s drain amount is • Repair or replace the
increase. ume is insufficient. large. pump.
• Depends on the motor’s • The motor’s volumetric ca- • Replace the motor.
function. pacity is dropping.
Oil is leaking. • Oil is leaking from oil • Lip is cut or damaged. • Replace the oil seal.
seals.
• Oil is leaking from mat- • Bolts are loose. • Tighten the bolts.
ing surfaces. • O-ring is cut or damaged. • Replace the O-ring.
• Mating surface is scratched. • Repair the surface with a
grind stone or sand paper.
Motor makes abnor- • Noise in piping. • Piping support is faulty. • Clamp the piping.
mal noise.
(The surface tempera- • Lubricating oil • Oil level is low. • Replenish the oil.
ture of the reduction • Hydraulic oil is getting in. • Replace the reduction gears.
gears case becomes • Gear unit • Bearings are damaged. • Replace the reduction gears.
high.) • Gear surfaces are damaged. • Replace the reduction gears.

IV-149 TB53FR
HYDRAULIC UNITS SLEW MOTOR

Anit-rebound Valve
Symptom Probable Causes Remedy
The motor does not Something other than the piston motor, valve Inspect the pressure at the entrance of the
rotate or its rota- unit or anti-rebound valve is malfunctioning. valve. Or, inspect individual units and ser-
tion speed is slow. vice as necessary.
The check valve assembly is not seated prop-
erly.
• Foreign matter is trapped. • Remove the foreign matter. Repair or
replace the faulty parts.
• The tightening torque of the anti-rebound • Use the prescribed tightening torque.
valve mounting bolt exceeds the prescribed
value.
The sleeve is malfunctioning.
• Foreign matter is trapped. • Remove the foreign matter. Repair or
replace the faulty parts.
The motor does not The check valve assembly is not seated prop-
stop or its stopping erly.
speed is slow. • Foreign matter is trapped. • Remove the foreign matter. Repair or
replace the faulty parts.
• The tightening torque of the anti-rebound • Use the prescribed tightening torque.
valve mounting bolt exceeds the prescribed
value.
The valve within the check valve assembly is
malfunctioning.
• Foreign matter is trapped. • Remove the foreign matter. Repair or
replace the faulty parts.
• Foreign matter is in the orifice of the valve. • Remove the foreign matter.
The sleeve is malfunctioning.
• Foreign matter is trapped. • Remove the foreign matter. Repair or
replace the faulty parts.
Slewing stops with The valve within the check valve assembly is
a great shock. malfunctioning.
• Foreign matter is trapped. • Remove the foreign matter. Repair or
replace the faulty parts.
• Foreign matter is in the orifice of the valve. • Remove the foreign matter.
The orifice is choked.
• Foreign matter is in the orifice of the anti- • Remove the foreign matter.
rebound valve body.
• Foreign matter is in the orifice of the valve • Remove the foreign matter.
unit.

TB53FR IV-150
SWIVEL JOINT HYDRAULIC UNITS
SWIVEL JOINT
CONSTRUCTION

12

10
5
13
9
7
6

2 1. Shaft
2. Hub
3. Flange
4. Thrust Ring
5. Pin
8
6. Slipper Seal
4
3
7. O-ring
11 8. O-ring
9. Backup Ring
10. Dust Seal
11. Snap Ring
12. Plug
J1D700 13. Dust Seal

OPERATION

The swivel joint is mounted in the center of the

machine’s slew axis. It serves the role of maintaining
continuous connections in the hydraulic circuit re-
gardless of the upper frame’s slew angle.
Above the hub (1) and shaft (2), which are capable of
rotating together, ports (3) are included for oil for the
necessary number of circuits only. The inner circum-
ference surface of the hub and the outer circumfer-
ence surface of the shaft, grooves are cut which serve
as passages for hydraulic oil. Seals (4) are placed
above and below these circumferential grooves.
Oil flowing in from a port flows constantly through
this hydraulic passage (5) between the hub and shaft
and the circuits can be connected without a break
when the upper frame is slewing.

IV-151 TB53FR
HYDRAULIC UNITS SWIVEL JOINT

DISASSEMBLY AND ASSEMBLY

General Cautions
• Carry out disassembly and assembly in a clean • Replace the seals with new ones each time the
work area and provide clean containers to hold the swivel joint is disassembled, applying a thin coat-
disassembled parts. ing of grease to them.
• Clean thoroughly around the ports and remove the • Check each part for abnormal wear or seizing. Also
paint on the joints of each part with a wire brush. remove any burrs or sharp edges, etc. with sandpa-
• Clean the disassembled parts with a cleaning fluid per or by a similar method.
such as diesel fuel. • Check for foreign matter or dirt, etc. in the seal
grooves.

The following describes the disassembly procedure.

For assembly, follow the disassembly procedure in
the reverse order.

Disassembly
1. Take out the bolts and remove the spring washers,
then remove the flange (1) from the hub.
Bolt: 24.5~39.2 N·m
• During assembly, place a pipe on the stopper
pin of the shaft and check if the shaft rotates.

2. Remove the O-ring (2), snap ring (3) and thrust

ring (4).
• During assembly, make sure the snap ring fist
securely in the groove.

3. Remove the shaft (5) from the hub.

• Place a knock pin (6) against the shaft end and
tap with a hammer. Select a knock pin (6) made
of copper or plastic, etc.
• Apply a thin coating of hydraulic oil or grease
to the outer circumference of the shaft.

TB53FR IV-152
SWIVEL JOINT HYDRAULIC UNITS
4. Remove the dust seal from the shaft.

5. Remove the seals from the inside diameter of the

hub.
• Check the positions of the seals in the struc-
tural drawing.
• Use an O-ring tooth or eyeleteer with a sharp
point on the end, etc.
• Do not deform or bend the slipper seal strongly
in any one place.
• During assembly, O-rings should not be twisted
when they are fitted in place.

IV-153 TB53FR
HYDRAULIC UNITS SWIVEL JOINT

INSPECTION AND ADJUSTMENT

Inspection Procedure and Treatment

Inspection Interval Place Inspected Inspection Procedure Treatment

2,000 hrs. Seals which prevent ex- Check if oil is leaking out Replace the O-rings if there
ternal leakage of hy- is leakage
draulic oil
4,000 hrs. All seal parts  Replace all seal parts
Disassemble and check All sliding parts Check for abnormal wear, Treat in accordance with the
whether there is leak- scratches, corrosion, etc., due use limit
age or not to seizing, biting of foreign mat-
ter, etc.
When disassembling All parts Check for abnormal wear, Treat in accordance with the
due to breakdown scratches, corrosion, etc., due use limit. However, replace
to seizing, biting of foreign mat- the seal kit
ter, etc.

Checking the Parts

Hub, Shaft
Parts Judgment Standard Treatment
Seal parts and sliding • Parts which wear away due to wearing of surfaces Replace with new parts
parts which have undergone ultrasonic tempering, and
parts which come off due to seizing, biting in of
foreign matter, etc.
Hub and shaft sliding • Parts with abnormal wear or with scratches 0.1 mm Replace with new parts
parts other than seals deep or deeper due to seizing or biting in of foreign
matter, etc.
• Parts with scratches less than 0.1 mm deep Repair with an oil stone
Portions which slide • Parts which are worn 0.5 mm or more, or abnormally Replace with new parts
against the thrust ring worn parts
• Parts with less than 0.5 mm of wear Repair so that it is smooth
• Parts with scratches due to seizing, biting in or Repair so that it is smooth
foreign matter, etc., which are within the wear limit
of 0.5 mm and which can be repaired

Flange
Parts Judgment Standard Treatment
Portions which slide • Parts which are worn 0.5 mm or more, or abnormally Replace with new parts
against the shaft end worn parts
• Parts with less than 0.5 mm of wear Repair so that it is smooth
• Parts with scratches due to seizing, biting in or Repair so that it is smooth
foreign matter, etc., which are within the wear limit
of 0.5 mm and which can be repaired

TB53FR IV-154
SWIVEL JOINT HYDRAULIC UNITS
Thrust Ring
Judgment Standard Treatment
• Parts which are worn 0.5 mm or more, or abnormally worn parts Replace with new parts
• Parts with less than 0.5 mm of wear Repair so that it is smooth
• Parts with scratches due to seizing, biting in or foreign matter, etc., which are Repair so that it is smooth
within the wear limit of 0.5 mm and which can be repaired

Inspection after Assembly

After assembly is completed, carry out a leak check of
each circuit using the apparatus shown in the figure.

1. Connect a pipe (3) from the hydraulic pump (2) to

the shaft (1) side port.
2. Connect a pressure gauge (5) to the hub (4) side.
3. Increase the pressure gradually to 20.6 MPa while
adjusting the relief valve (6), then perform a 1
minute leak test.
• Release the neighboring ports on both sides
and check visually for leakage from the ports.
• Check for external leakage, etc., by a color
check.

IV-155 TB53FR
HYDRAULIC UNITS SWIVEL JOINT

TROUBLESHOOTING

Symptom Probable Causes Remedy

External oil leakage • O-ring is defective •
Replace all the seal parts
Internal oil leakage • Thrust ring is defective •
Replace all the seal parts
• Great wear on sliding surfaces •
Replace the assembly
Shaft sticks • Shaft and hub are stuck together •
Carry out polishing and honing. If looseness
and oil leakage are great, replace the assem-
bly
Flange looseness • Socket bolt tightening is insuffi- • Retighten to the specified torque
cient

TB53FR IV-156
V . TROUBLESHOOTING

IV-157
V-1 TB53FR
TROUBLESHOOTING

CAUTIONS IN TROUBLESHOOTING AND REPAIRS

(1) Do not begin disassembling the equipment immediately just because it has broken down.
Conduct a thorough preliminary check before attempting disassembly.
a. Ask the user the following questions.
• What were the conditions when the machine broke down?
• Did anything abnormal happen before breakdown occurred?
• Are there any other places which were functioning poorly other than the part that broke
down?
• Are there any parts which have been repaired previous to the breakdown? What were
they?
• Has the same thing happened before?
b. Run the machine yourself and confirm the breakdown conditions.
• Judge whether the machine is really broken down or not following the judgment
standards.
The judgment on whether the machine has broken down may differ between individu-
als.

IMPORTANT: When running the machine, it is possible that moving the machine could
make the breakdown worse than it already is, so do not forget to ask the user if there is
anything to prevent your operating the machine.

c. Based on the information that you have gathered from the user and the information
obtained from running the machine yourself, judge the cause of the trouble. Also keep in
mind that it is difficult to reproduce the conditions of the breakdown again once the
machine has been disassembled, and early disassembly may make it impossible to
determine the true cause of the trouble. Therefore be sure to find the true cause of the
trouble before attempting disassembly.

(2) When it is thought that the trouble has more than one cause, begin investigating from the
simplest cause.

(3) Think over why the trouble could have occurred and try to correct the root cause of that
problem.

TB53FR IV-158
V-2
 TROUBLESHOOTING

CONTENTS

OVERALL MACHINE
No operations can be done. ................................................................................................................................... 4
All operations can be done, but there is no power. ............................................................................................... 5
The boom, bucket, slew and arm do not move at all, or the speed is low. ............................................................ 7
The boom cannot be raised or the left offset cannot be operated. The interference prevention system does not operate normally. ................. 9
MACHINE TRAVEL
The machine will not travel at all. ....................................................................................................................... 13
Right or left travel is impossible. ........................................................................................................................ 14
Speed drops in the left or right travel, causing the machine to travel in a curve. ............................................... 16
Machine won’t accelerate during travel. ............................................................................................................. 18
SLEWING
No slewing can be done. ...................................................................................................................................... 21
Right or left slewing cannot be done. .................................................................................................................. 24
Slewing speed is low, or there is no power. ........................................................................................................ 25
The machine slews, but overrun when slewing stops is great, or it cannot be stopped. ..................................... 27
BOOM
The boom cylinder doesn’t move. ....................................................................................................................... 29
Boom cylinder operation is slow, or there is no power. ...................................................................................... 31
The amount of boom natural drop is great. ......................................................................................................... 32
ARM
The arm cylinder doesn’t move. .......................................................................................................................... 33
Arm cylinder operation is slow, or there is no power. ........................................................................................ 35
The amount of arm natural drop is great. ............................................................................................................ 37
BUCKET
The bucket cylinder doesn’t move, or there is no power. ................................................................................... 38
The amount of bucket natural drop is great. ........................................................................................................ 40
OFFSET
The offset cylinder doesn’t move. ....................................................................................................................... 41
DOZER BLADE
The dozer blade cylinder doesn’t move, or there is no power. ............................................................................ 43
The amount of dozer blade natural drop is great or the dozer blade won’t hold the machine up. ...................... 45

V-3 TB53FR
TROUBLESHOOTING OVERALL MACHINE

NO OPERATIONS CAN BE DONE.

Inspect the hydraulic oil Insufficient Replenish the hydraulic

1 2
level oil.

Proper Amount

• Repair the pump or replace

Pump or coupling is
3 the pump.
faulty.
• Replace the coupling.

1. Inspect the hydraulic oil level.

“III. Machine Configuration, Hydraulic
Tank”

2. Replenish the hydraulic oil.

Take out the plug and replenish the hydraulic oil.
• The hydraulic oil supplied should be the same
brand as the oil currently in the tank.
“II. Specifications, Fluid Capacities”

3. Pump or coupling is faulty.

a. Disconnect the discharge hose (1) from the
pump side.
Also fit a plug in the disconnected hose to keep
the hydraulic oil from pouring out.
b. Disconnect the electrical wiring to the engine 1
stop solenoid (2).
c. Turn the engine over using the starting motor
and inspect if hydraulic oil is discharged by the
pump.
• The throttle lever should be in the engine
stop position.
If the pump is normal, hydraulic oil will be C4E001

discharged from it. If hydraulic oil is not dis-

charged, the pump or the coupling is faulty.

J1E002

TB53FR V-4
OVERALL MACHINE TROUBLESHOOTING
ALL OPERATIONS CAN BE DONE, BUT THERE IS NO POWER.

Inspect the hydraulic oil Insufficient Replenish the hydraulic

1 2
level. oil.

Proper Amount

Noise generated by the Noise Replace the seal tape, O-rings,

3 Suction line is faulty.
pump. hose.

No Noise

Bubbles from inside Treat beginning at the source

the tank. of the bubbling.

Inspect the main relief Faulty Repair or replace the main

4
valve. relief valve.

Normal

• Repair or replace the pump.

5 Pump is faulty.
• Flush with hydraulic oil.

1. Inspect the hydraulic oil level.

“III. Machine Configuration, Hydraulic
Tank”

2. Replenish the hydraulic oil.

“V-4”

3. Noise generated by the pump.

A faulty suction line can make it easy for cavita-
tion to occur in the pump and for noise to be
generated. Carry out the following inspect.
a. Inspect the piping used for suction of hydraulic
oil.
• Apply grease or oil to the part which appears
to be making the noise and inspect if there is
any change. (Inspect if it is sucking in air or
not.)
b. Inspect for clogging of the suction filter.

V-5 TB53FR
TROUBLESHOOTING OVERALL MACHINE

4. Inspect the main relief valve.

Measure the relief pressure of the main relief
valve.
• The valve is normal if the pressure gauge
reading is the standard value.
“ II. Specifications, Standards for Judging
Performance”

If the main relief valve’s set pressure is too low,

adjust it by tightening the valve set screw gradu-
ally.
• If the pressure doesn’t rise after 1/4 turn of the
screw, the main relief valve is faulty.

5. Pump is faulty.
If the pump is abnormally worn internally, or if it
is damaged, it is possible that pieces of metal are
mixed into the hydraulic oil. Therefore, carry out
the following treatment.
• Replace the spin filter cartridge.
• Replace the hydraulic oil or flush out the
hydraulic circuit.
(Up to NAS Class 9)

Caution : When replacing the hydraulic oil, be

sure to clean the inside of the Hydraulic Tank and
the suction strainer.
“III. Machine Configuration, Hydraulic
Tank”

If the pump seal is damaged, replace the seal.

“IV. Hydraulic Units, Hydraulic Pump”

TB53FR V-6
OVERALL MACHINE TROUBLESHOOTING
THE BOOM, BUCKET, SLEW AND ARM DO NOT MOVE AT ALL, OR THE SPEED IS LOW.

Inspect the hydraulic Faulty Repair or replace the hydrau-

1
pump P4. lic pump P4.

Normal

Faulty
2 Inspect the fuse. Replace the fuse.

Normal

Faulty Adjust or replace the limit

3 Inspect the limit switch.
switch.

Normal

Inspect the lever lock so- Faulty Repair or replace the lever lock
4
lenoid valve. solenoid valve.

Normal

Inspect the pilot relief Faulty Adjust, repair or replace the

5
valve. pilot relief valve.

Normal

Faulty Repair or replace the pilot

6 Inspect the pilot valve.
valve.

1. Inspect the hydraulic pump P4.

Inspect the hydraulic pump P4 (1) which is the
source of the hydraulic pressure for the pilot
valve. 
“V-4”
Since clogging of the line filter can also be con-
sidered, inspect and clean the filter.

."-!

V-7 TB53FR
TROUBLESHOOTING OVERALL MACHINE

2. Inspect the fuse.

Inspect the fuse for the electric power circuit that
operates the pilot solenoid valve.

."-"

3. Inspect the limit switch.

Set the lever stand to the operation position to turn
on the limit switch. Check the voltage at the lever
lock solenoid valve by using a tester.
• The limit switch is normal if the voltage is
being applied.

0.85RW

F4E005

4. Inspect the lever lock solenoid valve.

Inspect by the following procedure.
a. Turn the starter switch to the “ON” position.
b. Push lightly on the projection on the front end
of the solenoid valve.
c. Move the lever stand and change the limit
switch from “OFF” to “ON”.
d. If the spool moves and vibration can be felt
with the fingertip when the circuit changes,
then it is normal.

."-$

5. Inspect the pilot relief valve.

Measure the relief pressure of the pilot relief
valve.
• If the pressure is the standard value, the valve
is normal.
“II. Specifications, Standards for Judging
Performance”

6. Inspect the pilot valve.

“IV. Hydraulic Units, Pilot Valve”

TB53FR V-8
OVERALL MACHINE TROUBLESHOOTING
THE BOOM CANNOT BE RAISED OR THE LEFT OFFSET CANNOT BE OPERATED. THE INTER-
FERENCE PREVENTION SYSTEM DOES NOT OPERATE NORMALLY.

Is the attachment within Within the area Move the attachment out of
1 the interference preven- the interference prevention
tion area? area.
Outside the area

Faulty
2 Inspect the fuse. Replace the fuse.

Normal

Inspect the interference

3
prevention switch.

Normal

Inspect the interference Faulty Adjust, repair or replace the

4
prevention system. parts.

Normal

Inspect the pilot relief Faulty Adjust, repair or replace the

5
valve. pilot relief valve.

Normal

Faulty Repair or replace the pilot

6 Inspect the pilot valve
valve.

Normal

Faulty Repair or replace the control

7 Inspect the control valve.
valve.

1. Is the attachment within the interference pre-

vention area
When the boom cannot be raised or the left offset
cannot be operated at all, check whether the
attachment is within the interference prevention
area.
“III. Machine Configuration, Interference
Prevention System”
If the attachment is within the interference pre-
vention area, set the offset to the right and move
the attachment out of that area.

V-9 TB53FR
TROUBLESHOOTING OVERALL MACHINE

2. Inspect the fuse

Inspect the fuse of the power supply circuit that
operates the circuit of the interference prevention
system.

3. Inspect the interference prevention switch.

Turn the interference prevention switch “S. T. D
BUCKET” position.
While it is this condition, check if there is conti-
nuity with a tester.

."-"

4. Inspect the interference prevention system

<Boom switches A, B and C>
C
a. Inspect the wiring for inspecting the boom
switches. B
Remove the wiring (1) from the boom switches
A, B and C.
Apply the test prod on the positive (+) side of 1.25B
the tester to the terminal of the removed wiring
(wiring color is 1.25B) and ground the test
prod on the negative (-) side of the tester. Then,
turn the starter switch to the “ON” position and
check the voltage. 1
• If the voltage is 12 V, the wiring is in the A L2E008

normal state. If not, inspect the wiring for

the fault location.

b. Inspect the boom switch.

Remove the boom switch, press the tip of the
boom switch with your finger, and apply the 4 5
tester in between the terminals (4) and (5).
• If the boom switch is turned on at a stroke of
2±1 mm assuring conductance, the switch is
in the normal state.

L2E009

c. Confirm that the cam roller moves smoothly 1

along the cam plate (2) pushing the boom
switch.
Confirm that the offset switch is set in the state
with the stroke reduced by 4 mm from the free A B
2
state when the cam roller is on the cam plate
(2).
“III. Machine Configuration, Interfer- B
ence Prevention System”

J1C923

TB53FR V-10
OVERALL MACHINE TROUBLESHOOTING
<Offset switches R and L>
Turn on the boom switches A, B, and C.
“III. Machine Configuration, Interference B A
Prevention System” 0.85L
0.85BW
a. Inspect the wiring of the offset switches.
Remove the wiring from the offset switches R
and L.
Apply the test prod on the positive (+) side of
the tester to the terminal of the removed wiring
(wiring colors are 0.85L and 0.85BW) and
ground the test prod on the negative (-) side of
the tester. Then turn on the starter switch and
check the voltage.
• If the voltage is 12 V, the wiring is in the J1E010

normal state. If not, inspect the wiring for

the fault location.

b. Inspect the offset switches R and L.

Inspect the offset switches in a similar manner
as the boom switches. 4 5
“V-10”

L2E009

c. Confirm that the cam roller (3) moves smoothly

along with the angle (1), pushing the offset
switch.
Confirm that the offset switch is set in the state
with the stroke reduced by 4 mm from the free
state when the cam roller (3) is on the angle (1). 2
“III. Machine Configuration, Interfer-
ence Prevention System”
3

4
<Prevention Relay>
Turn on the boom switches A, B and C. 1 F4C918

“III. Machine Configuration, Interference

Prevention System”
a. Inspect the wiring of the interference preven- 7 0.85BW
tion relay.
Remove the wiring (7) from the interference
prevention relay (6). Apply the test prod on the - + 0.85R
positive (+) side of the tester to the terminal of
the removed wiring (wiring colors are 0.85BW
and 0.85R) and ground the test prod on the
negative (-) side of the tester. Then turn on the 6
starter switch and check the voltage.
• If the voltage is 12 V, the wiring is in the
normal state. If not, inspect the wiring for
the fault location. J1E011

V-11 TB53FR
TROUBLESHOOTING OVERALL MACHINE

b. Inspect the interference prevention relay.

Replace a normal speed relay (8) for the inter-
ference prevention relay (6) and inspect the 6
operation of the attachment. If the attachment
operates normally, it shows that the interfer-
ence prevention relay (6) is faulty.

J1E012

<Solenoid Valves>
Turn on the boom switches A, B and C.
“III. Machine Configuration, Interference 3 2 1
Prevention System”
a. Inspect the wiring of the solenoid valves 1, 2,
and 3. 0.85Y 0.85W
Remove the solenoid wiring (1), (2), and (3).
0.85W
Apply the terminal of each wiring (wiring
color are 0.85Y and 0.85W) to the test prod on SOL3

the positive (+) side of the tester and ground the SOL2
SOL1
test prod on the negative (-) side of the tester.
Then turn on the starter switch and check the
voltage.
• If the voltage is 12 V, the wiring is in the J1E013

normal state. If not, inspect the wiring for

the fault location.
b. Inspect the solenoids 1, 2, and 3.
“IV. Hydraulic Units, Solenoid Valve”
Solenoid 1 Stops left offset.
Solenoid 2 Stops boom raise.
Solenoid 3 Decelerates boom raise.

5. Inspect the pilot relief valve

Measure the pressure relieved through the pilot
relief valve.
• If the measured pressure is a reference value,
the valve is in the normal state.
“II. Specifications, Standards for Judging
Performance”

6. Inspect the pilot valve

“IV. Hydraulic Units, Pilot Valve and Pilot
Valve (Offset)”

7. Inspect the control valve

“IV. Hydraulic Units, Control Valve”

TB53FR V-12
MACHINE TRAVEL TROUBLESHOOTING
THE MACHINE WILL NOT TRAVEL AT ALL.

Inspect the pressure sup-

1 plied to the travel lever
lock cylinder.
Normal

Faulty Adjust, repair or replace the

2 Inspect the linkage.
linkage.

Normal

Inspect the travel lever Faulty Replace the travel lever lock
3
lock cylinder. cylinder.

1. Inspect the pressure supplied to the travel

lever lock cylinder.
Disconnect the hose between the solenoid valve
and the travel lever lock cylinder on the cylinder
side. Connect a pressure gauge to the discon-
nected hose and measure the pilot pressure.
• Keep the plug assembled on the port of the
disconnected cylinder.
• Standard value: Approx. 3.4 MPa

L2E014

2. Inspect the linkage.

Inspect the operating status of the travel lever
lock cylinder (1) and arm (2).
• The cylinder stroke should be 10 mm.
• Inspect the operating status of the lever lock
cylinder and arm. Also, check whether the
fixing bolt or nut is loose. 1

3. Inspect the travel lever lock cylinder.

The travel lever lock cylinder cannot be disas-
sembled. If it is faulty, replace it.

2 L2E015

V-13 TB53FR
TROUBLESHOOTING MACHINE TRAVEL

RIGHT OR LEFT TRAVEL IS IMPOSSIBLE.

Inspect the operation of

1 actuators other than the
travel motor.
Normal

Faulty Repair or replace the housing

2 Inspect spool operation.
block.

Normal

Faulty Adjust, repair or replace the

3 Inspect the linkage.
parts.

Normal

Faulty Repair or replace the swivel

4 Inspect the swivel joint.
joint.

Normal

Inspect the counterbal- Faulty Repair or replace the counter-

5
ance valve. balance valve.

Normal

Faulty Repair or replace the travel

6 Inspect the travel motor.
motor.

1. Inspect the operation of actuators other than Lever

the travel motor. Place Inspected
Operated
If operation of the right or left travel motor is
If right travel
impossible, operate each respective actuator in Boom Pump P1
is impossible Main Relief
accordance with the table at right. If operation is
If left travel is valve R1
faulty, inspect the main relief valve and pump. Arm Pump P2
impossible

2. Inspect spool operation.

• Spool Stroke : 8.0 mm
• If the spool is sticking, take it out and inspect
it. If it can’t be taken out, or if it is scratched,
replace the housing block.
Another cause of the spool not operating prop-
erly could be that the return spring installation
bolt is loose.

TB53FR V-14
MACHINE TRAVEL TROUBLESHOOTING
3. Inspect the linkage.
The inspection of the linkage is done by inspect-
ing the movement of the yoke (1) without the R
pin (2) and the pin (3) which connect the yoke (1)
and the spool.

4. Inspect the swivel joint.

• Disconnect the hose between the swivel joint
and the counterbalance valve from the coun-
terbalance valve side and set a pressure gauge
in the hose.
• Operate the travel lever and measure the pres-
sure.
• The swivel joint is normal if the pressure gauge
reading indicates the standard value.
Standard value: Approx. 20.6 MPa

5. Inspect the counterbalance valve.

• If neither forward nor reverse travel is pos-
sible, the spool (1) of the counterbalance valve
could be sticking in the neutral position.
• If either forward or reverse travel is possible,
the spool (1) of the counterbalance valve could
be sticking in a position other than the neutral
position.
• Disconnect the counterbalance valve plug (2)
and try pushing the spool (1) with a finger. It is
normal if it moves smoothly about 6 mm.

6. Inspect the travel motor.

“IV. Hydraulic Units, Travel Motor”

V-15 TB53FR
TROUBLESHOOTING MACHINE TRAVEL

SPEED DROPS IN THE LEFT OR RIGHT TRAVEL, CAUSING THE MACHINE TO TRAVEL IN A CURVE.

Within
Is the amount of travel standard Depends on the com-
1 Normal
curve within standard? bination of equipment.

Not within Standard

Inspect the crawler ten- Faulty Adjust to the proper dimen-

2 sion and inspect for for- sions or remove the foreign
eign matter biting in, etc. matter.
Not abnormal

Inspect the operation of Faulty Repair or replace the housing

3
the spool. block.

Normal
The direction of travel curve
• Repair the pump or replace it.
Switch the left and right changes to the opposite side.
4 • Replace the hydraulic oil
pump discharge hoses.
and filter.
No change
The direction of travel
curve changes to the
Switch the left and right opposite side.
Inspect the main relief Repair or replace the main
5 main relief valves and
valve. relief valve.
test.
No change

Faulty Repair or replace the swivel

6 Inspect the swivel joint.
joint.

Normal

Inspect the counterbal- Faulty Repair or replace the counter-

7
ance valve. balance valve.

Normal

The travel motor’s speed Repair or replace the travel

8
reducer unit is faulty. motor.

1. Is the amount of travel curve within stan-

dard?
If the amount of travel curve is within standards,
then operation is normal and the variation de-
pends on the combination of equipment.
“II. Specifications, Standards for Judging
Performance”

2. Adjust the tension of the crawler belt.

“II. Specifications, Standards for Judging
Performance”

TB53FR V-16
MACHINE TRAVEL TROUBLESHOOTING
3. Inspect the operation of the spool.
“V-14”

4. Switch the left and right pump discharge

hoses.
Switch the discharge hoses for Pump P1 and
Pump P2. The pump is faulty if the direction in
which the machine curves during travel is in the
opposite direction.
• Disassemble and inspect the pump.
“IV. Hydraulic Units, Hydraulic Pump”

5. Switch the left and right main relief valves

and test.
Switch the left and right main relief valves and
test. If the direction in which the machine curves
during travel changes to the opposite direction,
the main relief valve is faulty.
• Inspect the main relief valve
“V-6”

J1E014

6. Inspect the swivel joint.

“V-15”

7. Inspect the counterbalance valve.

Inspect if the counterbalance valve’s plunger
moves smoothly.
“V-15”

8. The travel motor’s speed reducer unit is

faulty.
“IV. Hydraulic Units, Hydraulic Pump”

V-17 TB53FR
TROUBLESHOOTING MACHINE TRAVEL

MACHINE WON’T ACCELERATE DURING TRAVEL.

Inspect the hydraulic Faulty Repair or replace the hydrau-

1
pump P4. lic pump P4.

Normal

Inspect the pilot relief Faulty Adjust, repair or replace the

2
valve. pilot relief valve.

Normal

Faulty
3 Inspect the fuse. Replace the fuse.

Normal

Inspect the travel speed Faulty Replace the travel speed

4
switch. switch.

Normal

Inspect the 2nd speed re- Faulty

5 Replace the 2nd speed relay.
lay.

Normal

Inspect the 2nd speed Faulty Repair or replace the 2nd

6
solenoid valve. speed solenoid valve.

Normal

Faulty Repair or replace the swivel

7 Inspect the swivel joint.
joint.

Normal

The 2nd speed control Faulty Repair or replace the 2nd

8
valve is faulty. speed control valve.

1. Inspect the hydraulic pump P4.

Inspect the hydraulic pump P4 which is the
source of the hydraulic pressure for switching to
second gear.
“V-7”
Since clogging of the line filter can also be
considered, inspect and clean the filter.

TB53FR V-18
MACHINE TRAVEL TROUBLESHOOTING
2. Inspect the pilot relief valve.
Measure the relief pressure of the pilot relief
valve.
• If the pressure is the standard value, the valve
is normal.
“II. Specifications, Standards for Judging
Performance”

3. Inspect the fuse.

Operate the 2nd speed solenoid valve and check
the fuse for the power supply circuit.

."-#

4. Inspect the travel speed switch.

Press the switch to turn it “ON”. While it is in this
condition, check if there is continuity with a
tester.

5. Inspect the 2nd speed relay.

Press the travel speed switch to turn the second
speed relays (1) to “ON.” Check whether the
voltage is applied to the second speed solenoid
valve by using a tester. Be sure to stop the engine
before starting the inspection.

0.85RY J1E015

V-19 TB53FR
TROUBLESHOOTING MACHINE TRAVEL

6. Inspect the 2nd speed solenoid valve.

a. Turn the start switch “ON”.
b. Press the protruding portion of the solenoid
valve lightly.
c. Turn the travel speed switch “ON”.
d. If the spool moves and vibration can be felt
with the fingertip when the circuit changes,
then it is normal.

."-%

7. Inspect the swivel joint.

Disconnect the hose between the swivel joint and
the 2nd speed control valve at the 2nd speed
control valve side. Set a pressure gauge in the
disconnected end of the hose and turn on the 2nd
speed switch.
• A pressure of 3.4 MPa is normal.

C4E013

8. The 2nd speed control valve is faulty.

Check if the plunger of the 2nd speed control
valve is sticking or if foreign matter is caught in
it.
“IV. Hydraulic Units, Travel Motor”

TB53FR V-20
SLEWING TROUBLESHOOTING
NO SLEWING CAN BE DONE.

Inspect the operation of

1 actuators other than the
slew motor.
Normal

Faulty Repair or replace the pilot

2 Inspect the pilot valve.
valve.

Normal

Faulty Repair or replace the shuttle

3 Inspect the shuttle valve.
valve.

Normal

Inspect the operation of Faulty Repair or replace the housing

4
the spool. block.

Normal

Inspect the slew hydrau- Pressure is low. Adjust the slew relief
5 Adjust the set pressure.
lic pressure. valve pressure.

Normal

Pressure does not rise Repair or replace the slew re-

lief valve.

Faulty Repair or replace the slew

6 Inspect the slew motor.
motor.

Normal

The slew bearing is faulty. Replace.

1. Inspect the operation of actuators other than

the slew motor.
Inspect if the operation of the slew motor only is Lever Operated Places inspected
faulty by the table at right. If its operation is
Dozer Blade Relief Valve R3 Pump P3
faulty, inspect the main relief valve and the hy-
draulic pump.
“V-6”

V-21 TB53FR
TROUBLESHOOTING SLEWING

2. Inspect the pilot valve.

Disconnect the hose between the pilot valve and
control valve (slew section) at the control valve
side, then set a pressure gauge in the disconnected
hose.
• A plug should be inserted in the control valve
port.
• Operate the lever (slew) and measure the pres-
sure.
• Depending on the operating angle, a pressure
in the 0~3.4 MPa range is normal.

3. Inspect the shuttle valve.

Disconnect the hose that goes between the shuttle
valve and the slew motor at the slew motor side
and set a pressure gauge to the disconnected hose.
• Operate the lever (slew) and measure the pres-
sure.
• The shuttle valve is normal if between 0 and
3.4 MPa corresponding to the operation angle.

4. Inspect the operation of the spool.

Disconnect the hose that goes between the control
valve (slew section) and the slew motor at the
valve side and set a pressure gauge to the dis-
charge port of the valve.
• Operate the lever (slew) and measure the pres-
sure.
• The operation of the spool is normal if it agrees
with the following value of supply pressure:
18.6 MPa

5. Inspect the slew hydraulic pressure.

Measure the pressure at the left and right slew
relief valves.
• The pressure is normal if it is the standard
value.
“II. Specifications, Standards for Judging
Performance”
If adjustment of the pressure is possible, the slew
relief valve’s adjustment is faulty. Also, if the
pressure adjustment is impossible, the slew relief
valve is faulty.

TB53FR V-22
SLEWING TROUBLESHOOTING
6. Inspect the slew motor.
Separate the slew motor (1) and the turntable (2),
then try turning the turntable (2).
• Turntable turns................ Faulty slew motor (1).
• Turntable doesn’t turn .... Faulty slew bearing (3).
“IV. Hydraulic Units, Slew Motor”

V-23 TB53FR
TROUBLESHOOTING SLEWING

RIGHT OR LEFT SLEWING CANNOT BE DONE.

Faulty Repair or replace the pilot

1 Inspect the pilot valve.
valve.

Normal

Inspect the operation of Faulty Repair or replace the housing

2
the spool. block.

Normal

Inspect the slew relief Faulty Repair or replace the slew re-
3
valve. lief valve.

Normal

Inspect the check valve Faulty Repair or replace the slew

4
of the slew brake valve. brake valve.

Normal

Repair or replace the slew

5 The slew motor is faulty.
motor.

1. Inspect the pilot valve.

It could be that the spool for only the side of the
pilot valve for which slewing is impossible will
not operate.
“V-22”

2. Inspect the operation of the spool.

It could be that the spool will not move only in the
direction in which slewing is impossible.
“V-22”

3. Inspect the slew relief valve.

Try switching the left and right slew relief valves.
If slewing becomes possible, the relief valve is
faulty.

4. Inspect the check valve of the slew brake

valve.
If foreign matter is caught in one end of the check
valve, or if the valve is sticking, right or left
slewing will be impossible.
• If foreign matter is caught in one of the check
valves, the hydraulic oil returns to the tank
from the check valve.

5. The slew motor is faulty.

“IV. Hydraulic Units, Sew Motor”

TB53FR V-24
SLEWING TROUBLESHOOTING
SLEWING SPEED IS LOW, OR THERE IS NO POWER.

Is the time needed for Within the standard.

1 slewing within the stan- Normal
dard?
Not within the standard

Faulty Repair or replace the pilot

2 Inspect the pilot valve.
valve.

Normal

Inspect the operation of Faulty Repair or replace the housing

3
the spool. block.

Normal

Inspect the slew hydrau- Pressure is low. Adjust the pressure of

4 Adjust the set pressure.
lic pressure. the slew relief valve.

Normal

Pressure does not rise. Repair or replace the slew re-

lief valve.

Inspect the check valve Faulty Repair or replace the slew

5
of the slew brake valve. brake valve.

Normal

Inspect the slew motor Faulty Repair or replace the slew

6
drainage amount. motor.

Normal

Inspect the slew reduc- Faulty Repair or replace the slew re-
7
tion gear. duction gear.

Normal

The slew bearing is faulty. Replace.

V-25 TB53FR
TROUBLESHOOTING SLEWING

1. Is the time needed for slewing within the

standard?
“II. Specifications, Standards for Judging
Performance”

2. Inspect the pilot valve.

“V-22”

3. Inspect the operation of the spool.

“V-22”

4. Inspect the slew hydraulic pressure.

“V-22”

5. Inspect the check valve of the slew brake

valve.
“V-24”

6. Inspect the slew motor drainage amount.

Operate the slew motor under the following con-
ditions and measure the amount of oil which
drains out in 1 minute.
a. Disconnect the drain hose (1) connected to the
motor and insert a plug (2) in the end of the
disconnected hose.
b. Install a hose (3) for measuring the drainage
amount in the motor’s drain port.
c. Operate the motor for 1 minute and measure
the drainage amount. If it is as follows, the
drainage amount is normal.
Hydraulic Oil Temp.: 50~60°C
Engine Speed: Rated Speed
Drainage Amount: 0.5 L/min or less

7. Inspect the slew reduction gear.

“IV. Hydraulic Units, Slew Motor”

TB53FR V-26
SLEWING MACHINE CONFIGURATION
THE MACHINE SLEWS, BUT OVERRUN WHEN SLEWING STOPS IS GREAT, OR IT CANNOT BE STOPPED.

Is the amount of overrun Within the standard.

1 when slewing stops Normal.
within the standard?
Not within the standard.

Faulty Repair or replace the pilot

2 Inspect the pilot valve.
valve.

Normal

Inspect the operation of Faulty Repair or replace the housing

3
the spool. block.

Normal

Inspect the check valve Faulty

4 Repair replace the brake valve.
of the slew brake valve.

Normal

Inspect the slew hydrau- Pressure is low. Adjust the pressure of

5 Adjust the set pressure.
lic pressure. the slew relief valve.

Pressure doesn’t rise Repair or replace the slew re-

lief valve.

1. Is the amount of overrun when slewing stops

within the standard?
“II. Specifications, Standards for Judging
Performance”

2. Inspect the pilot valve.

Inspect if the spool of the pilot valve returns to the
neutral position when the operation lever (slew)
is released after operation. Disconnect the hose
between the pilot valve and the control valve
(slew section) on the control valve side, then set
a pressure gauge in the disconnected hose.
• Read the pressure gauge after operating the
lever (slew), then releasing it.
• If the pressure is zero, the pilot valve is normal.

V-27 TB53FR
TROUBLESHOOTING SLEWING

3. Inspect the operation of the spool.

Inspect if the spool of the control valve (slew
section) returns to the neutral position when the
operation lever (slew) is released after operation.
Disconnect the line from the slew section of the
control valve, then set a pressure gauge in its
supply port.
• Read the pressure gauge after operating the
lever (slew), then releasing it.
• If the pressure is zero, the pilot valve is normal.

4. Inspect the check valve of the slew brake

valve.
If the slew lever returns to the neutral position, the
upper frame may try to stop, but if some foreign
object is caught in the check valve, the return oil
ends up flowing to the supply side. For that
reason, the amount of overrun when slewing
stops is great during slew stopping.

5. Inspect the slew hydraulic pressure.

“V-22”

TB53FR V-28
BOOM MACHINE CONFIGURATION
THE BOOM CYLINDER DOESN’T MOVE.

Inspect the operation of

1 actuators other than the
boom cylinder.
Normal

Faulty Repair or replace the pilot

2 Inspect the pilot valve.
valve.

Normal

Inspect the operation of Faulty Repair or replace the housing

3
the spool. block.

Normal
Operation
Perform a port relief became normal. The port relief valve is Repair or replace the port re-
4
valve switching test. faulty. lief valve.

Does not change.

Inspect the boom cylin- Faulty Repair or replace the boom

5
der. cylinder.

1. Inspect the operation of actuators other than

the boom cylinder.
Inspect if the operation of the boom cylinder only Lever Operated Places inspected
is faulty by the table at right. If its operation is
faulty, inspect the main relief valve and the hy- Right Travel Relief Valve R1 Pump P1
draulic pump.
“V-6”

V-29 TB53FR
TROUBLESHOOTING BOOM

2. Inspect the pilot valve.

Disconnect the hose between the pilot valve and
control valve (boom section) on the control valve
side, then set a pressure gauge in the disconnected
hose.
• Operate the (boom) lever and measure the
pressure.
• Depending the operation angle, if the pressure
is normal, it will range between 0~3.4 MPa.

3. Inspect the operation of the spool.

Disconnect the hose between the control valve
(boom section) and the cylinder on the cylinder
side, then set a pressure gauge in the disconnected
hose.
• Operate the (boom) lever and measure the
pressure.
• A pressure of 20.6 MPa is normal.

4. Perform a port relief valve switching test.

Switch the port relief valve for the port relief
valve of the normal arm. If the boom cylinder
operates, the boom side port relief valve is faulty.

J1E016

5. Inspect the boom cylinder.

a. Disconnect the hose between the control valve
and the boom cylinder on the control valve
side.
b. Connect the disconnected hose to the arm
section or the bucket section.
c. Try operating the boom cylinder. If the cylin-
der doesn’t operate, the cylinder is faulty.
When performing the operation in “a~c”
above, the bucket cylinder should be fully
extended, the arm cylinder should be fully
retracted and the bucket should be lowered
to the ground.

TB53FR V-30
BOOM MACHINE CONFIGURATION
BOOM CYLINDER OPERATION IS SLOW, OR THERE IS NO POWER.

Is the boom cylinder’s Within the standard.

1 speed within the stan- Normal
dard?
Not within the standard.

Faulty Repair or replace the pilot

2 Inspect the pilot valve.
valve.

Normal

Inspect the operation of Faulty Repair or replace the housing

3
the spool. block.

Normal
Operation
Perform a port relief became normal. The port relief valve is Repair or replace the port re-
4
valve switching test. faulty. lief valve.

Does not change

Inspect the boom cylin- Faulty Repair or replace the boom

5
der. cylinder.

1. Is the boom cylinder’s speed within the stan-

dard?
“II. Specifications, Standards for Judging
Performance”

2. Inspect the pilot valve.

“V-30”

3. Inspect the operation of the spool.

“V-30”

4. Perform a port relief valve switching test.

“V-30”

5. Inspect the boom cylinder.

“IV. Hydraulic Units, Cylinders”

V-31 TB53FR
TROUBLESHOOTING BOOM

THE AMOUNT OF BOOM NATURAL DROP IS GREAT.

Is the amount of natural Within the standard.

1 Normal
fall within the standard?

Not within the standard.

Inspect for internal leak- Faulty Repair or replace the boom

2
age in the boom cylinder. cylinder.

Normal
Operation be-
Perform a port relief came normal The port relief valve is Repair or replace the port re-
3
valve switching test. faulty. lief valve.

Does not change

The control valve is leaking

Replace the housing block.
internally.

1. Is the amount of natural drop within the

standard?
“II. Specifications, Standards for Judging
Performance”

2. Inspect for internal leakage in the boom

cylinder.

3. Perform a port relief valve switching test.

“V-30”

TB53FR V-32
ARM MACHINE CONFIGURATION
THE ARM CYLINDER DOESN’T MOVE.

Inspect the operation of

1 actuators other than the
arm cylinder.
Normal

Faulty Repair or replace the pilot

2 Inspect the pilot valve.
valve.

Normal

Inspect the operation of Faulty Repair or replace the housing

3
the spool. block.

Normal
Operation
Perform a port relief became normal. The port relief valve is Repair or replace the port re-
4
valve switching test. faulty. lief valve.

Does not change

Faulty Repair or replace the arm cyl-

5 Inspect the arm cylinder.
inder.

1. Inspect the operation of actuators other than

the arm cylinder.
Inspect if the operation of the arm only is faulty by Lever Operated Places inspected
the table at right. If operation is faulty, inspect the
main relief valve and the hydraulic pump. Left Travel Relief Valve R2 Pump P2
“V-6”

2. Inspect the pilot valve.

“V-30”

V-33 TB53FR
TROUBLESHOOTING ARM

3. Inspect the operation of the spool.

Disconnect the arm hose connected to the pipe at
the boom foot, then set a pressure gauge in the
disconnected hose.
• Operate the (arm) lever and measure the pres-
sure.
• If the pressure is 20.6 MPa, it is normal.

J1E017

4. Perform a port relief valve switching test.

Switch the port relief valve with that of the
normal boom. If the arm cylinder then operates,
the port relief valve is faulty.

J1E016

5. Inspect the arm cylinder.

Switch the arm hoses and bucket hoses connected
to the pipes at the boom foot.
• Try operating the (bucket) operation lever to
operate the arm cylinder.
• If the cylinder doesn’t operate, the cylinder is
faulty.
When performing the operation above, the
bucket cylinder should be fully extended, the
arm cylinder should be fully retracted, and
the bucket should be lowered to the ground.

TB53FR V-34
ARM MACHINE CONFIGURATION
ARM CYLINDER OPERATION IS SLOW, OR THERE IS NO POWER.

Is the arm cylinder’s Within the standard.

1 speed within the stan- Normal
dard?
Not within the standard.

Faulty Repair or replace the pilot

2 Inspect the pilot valve.
valve.

Normal

Inspect the operation of Faulty Repair or replace the housing

3
the spool. block.

Normal
Operation
Perform a port relief became normal. The port relief valve is Repair or replace the port re-
4
valve switching test. faulty. lief valve.

Does not change

Faulty Repair or replace the arm cyl-

5 Inspect the arm cylinder.
inder.

1. Is the arm cylinder’s speed within the stan-

dard?
“II. Specifications, Standards for Judging
Performance”

2. Inspect the pilot valve.

“V-30”

3. Inspect the operation of the spool.

“V-34”

4. Perform a port relief valve switching test.

“V-34”

V-35 TB53FR
TROUBLESHOOTING ARM

5. Inspect the arm cylinder.

a. Fully retract the bucket cylinder, fully retract
the arm cylinder and lower the bucket to the
ground.

b. Disconnect the two hoses connected to the

cylinder. Insert plugs (1) in the disconnected
hoses and the cylinder piping.

c. Raise the boom and raise the hoe attachment so

it floats above the ground. If the arm dorps, the
cylinder is faulty. If the arm does not drop,
there is leakage inside the control valve.

TB53FR V-36
ARM MACHINE CONFIGURATION
THE AMOUNT OF ARM NATURAL DROP IS GREAT.

Is the amount of natural Within the standard.

1 Normal
fall within the standard?

Not within the standard.

Faulty Repair or replace the arm cyl-

2 Inspect the arm cylinder.
inder.

Normal

There is leakage inside

3 Replace the housing block.
the control valve.

1. Is the amount of natural fall within the stan-

dard?
“II. Specifications, Standards for Judging
Performance”

2. Inspect the arm cylinder.

“V-36”

V-37 TB53FR
TROUBLESHOOTING BUCKET

THE BUCKET CYLINDER DOESN’T MOVE, OR THERE IS NO POWER.

Inspect the operation of

1 actuators other than the
bucket cylinder.
Normal

Faulty Repair or replace the pilot

2 Inspect the pilot valve.
valve.

Normal

Inspect the operation of Faulty Repair or replace the housing

3
the spool. block.

Normal
Operation
Perform a port relief became normal. The port relief valve is Repair or replace the port re-
4
valve switching test. faulty. lief valve.

Does not change.

Inspect the bucket cylin- Faulty Repair or replace the bucket

5
der. cylinder.

1. Inspect the operation of actuators other than

the bucket cylinder.
Inspect if the operation of the bucket only is faulty Lever Operated Places inspected
by the table at right. If operation is faulty, inspect
the main relief valve and the hydraulic pump. Right Travel Relief Valve R1 Pump P1
“V-6”

2. Inspect the pilot valve.

“V-30”

3. Inspect the operation of the spool.

“V-34”

TB53FR V-38
BUCKET MACHINE CONFIGURATION
4. Perform a port relief valve switching test.
When only “bucket load” side is inoperable:
Replace the port relief valve with that of the
normal boom, and test. If the bucket cylinder
operates, the replaced old port relief valve was
faulty.

J1E018

5. Inspect the bucket cylinder.

At the boom foot, exchange the arm hose with the
bucket hose that is connected to the pipe.
• Move the lever (arm) and check whether the
bucket cylinder operates.
• If the bucket cylinder does not operate, the
bucket cylinder is faulty.

This inspection should be done with the

bucket cylinder fully extended and the arm
cylinder fully retracted. Also, the bucket must
be lowered to the ground.

V-39 TB53FR
TROUBLESHOOTING BUCKET

THE AMOUNT OF BUCKET NATURAL DROP IS GREAT.

Is the amount of natural Within the standard.

1 Normal
fall within the standard?

Not within the standard.

Inspect the bucket cylin- Faulty Repair or replace the bucket

2
der. cylinder.

Normal

There is leakage inside

3 Replace the housing block.
the control valve.

1. Is the amount of natural drop within the

standard?
“II, Specifications, Standards for Judging
Performance”

2. Inspect the bucket cylinder.

a. Fully extend the bucket cylinder, fully retract
the arm cylinder and lower the bucket to the
ground,
b. Disconnect the 2 hoses connected to the cylin-
der.
Insert the plugs (1) in the disconnected hoses
and the piping.

c. Raise the boom and raise the hoe attachment so

that it floats above the ground, If the bucket
drops, the cylinder is faulty, If the bucket does
not drop, there is leakage inside the control
valve.

TB53FR V-40
OFFSET MACHINE CONFIGURATION
THE OFFSET CYLINDER DOESN’T MOVE.

Inspect the operation of

1 actuators other than the
offset cylinder.
Normal

Inspect the pilot valve Faulty Repair or replace the pilot

2
(offset). valve (offset).

Normal

Inspect the interference Faulty Adjust, repair or replace the

3
prevention system. parts.

Normal

Inspect the operation of Faulty Repair or replace the housing

4
the spool. block.

Normal

Inspect the offset cylin- Faulty Repair or replace the offset

5
der. cylinder.

1. Inspect the operation of actuators other than

the offset cylinder.
Inspect if the operation of the offset only is faulty Lever Operated Places inspected
by the table at right. If operation is faulty, inspect
the main relief valve and the hydraulic pump. Left Travel Relief Valve R2 Pump P2
“V-6”

2. Inspect the pilot valve (offset).

Disconnect the hose between the pilot valve and
solenoid valve on the solenoid valve side, then set
a pressure gauge in the disconnected hose.
• Operate the offset pedal and measure the pres-
sure.
• Depending the operation angle, if the pressure
is normal, it will range between 0~3.4 MPa

L2E028

V-41 TB53FR
TROUBLESHOOTING OFFSET

3. Inspect the interference prevention system.

If the left offset cannot be operated while the right
offset can be operated normally, the interference
prevention system is faulty.
“V-10~12”

4. Inspect the operation of the spool.

Disconnect the hose between the control valve
(offset section) and the cylinder on the cylinder
side, then set a pressure gauge in the disconnected
hose.
• Operate the offset pedal and measure the pres-
sure.
• A pressure of 20.6 MPa is normal.

5. Inspect the offset cylinder.

“IV. Hydraulic Units, Cylinders”

TB53FR V-42
DOZER BLADE MACHINE CONFIGURATION
THE DOZER BLADE CYLINDER DOESN’T MOVE, OR THERE IS NO POWER.

Inspect the operation of

1 actuators other than the
dozer blade cylinder.
Normal

Inspect the operation of Faulty Repair or replace the housing

2
the spool. block.

Normal

Faulty Adjust, repair or replace the

3 Inspect the linkage.
parts.

Normal

Inspect the control valve Faulty Repair or replace the housing

4
supply pressure. block.

Normal

Faulty Repair or replace the swivel

5 Inspect the swivel joint.
joint.

Normal

The dozer blade cylinder is Faulty Repair or replace the dozer

faulty. blade cylinder.

1. Inspect the operation of actuators other than

the dozer blade cylinder.
Inspect if the operation of the dozer blade only is Lever Operated Places inspected
faulty by the table at right. If operation is faulty,
inspect the main relief valve and the hydraulic Slew Relief Valve R3 Pump P3
pump.
“V-6”

2. Inspect the operation of the spool.

“V-14”

3. Inspect the linkage.

“V-15”

V-43 TB53FR
TROUBLESHOOTING DOZER BLADE

4. Inspect the control valve supply pressure.

Disconnect one of the hoses connected to the
dozer blade section of the control valve. Set a
pressure gauge in its section, operate the dozer
blade operation lever and inspect the supply pres-
sure.
If the pressure indicated is not the value below,
the housing block is faulty.
• Supply Pressure: 19.6 MPa

5. Inspect the swivel joint.

Disconnect the hose between the swivel joint and
the dozer blade cylinder on the cylinder side.
Connect a pressure gauge to the disconnected
hose and operate the lever (blade).
• If the measured pressure is not the following
value, the swivel joint is faulty.
Supply pressure: 19.6 MPa

TB53FR V-44
DOZER BLADE MACHINE CONFIGURATION
THE AMOUNT OF DOZER BLADE NATURAL DROP IS GREAT OR THE DOZER BLADE WON’T
HOLD THE MACHINE UP.

Is the amount of natural Within the standard.

1 Normal
drop within the standard?

Not within the standard.

Inspect for internal leak- Faulty Repair or replace the housing

2
age in the blade cylinder. block.

Normal

Repair or replace the swivel

Inspect the swivel joint Faulty
3 joint, or replace the control
and control valve.
valve.

1. Is the dozer blade’s natural drop within the

standard?
“II. Specifications, Standards for Judging
Performance”

2. Inspect for internal leakage in the dozer

blade cylinder.
a. Using the hoe attachment, raise the machine’s
body, then lower the dozer blade fully.

b. Disconnect the dozer blade cylinder’s rod side

hose and drain out the oil in the piping.
Insert a plug (1) in the disconnected hose.

V-45 TB53FR
TROUBLESHOOTING DOZER BLADE

c. Raise the boom and apply a load on the dozer

blade.
• If the machine’s body drops while oil drains
out of the cylinder’s piping, the cylinder is
faulty.
If the body drops even though no oil drains out,
the control valve or the swivel joint is faulty.

If the machine cannot be supported by the

dozer blade, try replacing the port relief valve
with a normal one.
If the dozer blade can support the machine’s
body after this, then the port relief valve is
faulty.

3. Inspect the swivel joint and control valve.

Disconnect the hose between the swivel joint and
control valve at the control valve side, then insert
a plug in the disconnected hose.
Apply a load to the dozer blade by the procedure
in the previous item 2, a~c.
If the machine’s body drops, the swivel joint is
faulty.
If the machine’s body does not drop, there is
internal leakage in the control valve.

TB53FR V-46
VI . ENGINE

V-47 TB53FR