GROUP 3 TESTS AND ADJUSTMENTS

1. HYDRAULIC OIL CLEAN UP PROCEDURE USING PORTABLE FILTER CADDY

Ɠ Service equipment and tool
şPortable filter caddy
şTwo 4000mm ź 1in 100R1 Hoses
şQuick disconnect fittings.
şDischarge wand
şVarious size fittings.
Ɠ Brake system uses oil from hydraulic
reservoir. Flush all lines in the brake,
pilot, steering system and cut off
system. Disassemble and clean major
components for brake and steering
system. Remove and clean pilot caps
from main control valve.
Brake and steering components may fail
if brake and steering system is not
cleaned after hydraulic reservoir
contamination.
1) If hydraulic system is contaminated due to a
major component failure, remove and
disassemble steering cylinders to clean
debris from cylinders.
2) Install a new return filter element. Inspect
filter housing before installing new element.
Ɠ For a failure that creates a lot of debris,
remove access cover from reservoir.
Drain and clean reservoir of fill the
specified oil to reservoir through upper
cover.
3) To minimize oil loss, pull a vacuum in
reservoir using a vacuum pump. Connect
filter caddy suction line to drain port at
bottom of reservoir using connector. Check
to be sure debris has not closed drain port.
4) Put filter caddy discharge line into reservoir
filler hole so end is as far away from drain
port as possible to obtain a thorough
cleaning of oil.

6 -53
5) Start the filter caddy. Check to be sure oil is
flowing through the filters.
Operate filter caddy approximately 10
minutes so oil in reservoir is circulated
through filter a minimum of four times.
Ɠ Reservoir capacity : 75ֻ(19.8U.S. gal)
Leave filter caddy operation for the next
steps.
6) Start the engine and run it at high idle.
Ɠ For the most effective results, cleaning
procedure must start with the smallest
capacity circuit then proceed to the next
largest capacity circuit.
7) Operate all functions, one at a time, through
a complete cycle in the following order:
Clam, steering, bucket, and boom. Also
include all auxiliary hydraulic functions.
Repeat procedure until the total system
capacity has circulated through filter caddy
seven times, approximately 30 minutes.
Each function must go through a minimum
of three complete cycles for a through
cleaning for oil.
Ɠ Filtering time for machines with auxiliary
hydraulic functions must be increased
because system capacity is larger.
8) Stop the engine. Remove the filter caddy.
9) Install a new return filter element.
10) Check oil level in reservoir ; Add oil if
necessary.

6 -54
2. BOOM HEIGHT KICKOUT ADJUSTMENT
1) Lift the boom up to a desired height, set the
boom control lever at hold, then stop the Proximity switch
engine. Front frame
Plate
Be careful lest work equipment fall
down.
Put the hydraulic safety lock lever in the
LOCK position.
Boom

2) Loosen bolts then tighten them after

Proximity switch Plate(A)
adjusting the plate(A) so that it comes in
contact with the center of the probe of the Plate Bolt
proximate switch.

Boom

3) Loosen the nuts so that a clearance Proximity switch

between the plate(B) and the probe of the
Nut
proximate switch are 3Ź1mm. Plate(B)

3Ź1mm

4) Start the engine. Position the bucket on

Detent position
the ground. Then lift the bucket to a
desired height by using the control lever
and release the hand.
Confirm the lever automatically returns to
the neutral position and the boom(The
bucket) stop at the adjusted position.

6 -55
3. TEST TOOLS
1) CLAMP-ON ELECTRONIC TACHOMETER
INSTALLATION
şService equipment and tools
Tachometer
A : Clamp on tachometer.
Remove paint using emery cloth and B
connect to a straight section of injection D
line within 100mm(4in) of pump. Finger C
tighten only-do not over tighten.
B : Black clip(-). Connect to main frame.
C : Red clip(+). Connect to transducer. A
D : Tachometer readout. Install cable.

2) DIGITAL THERMOMETER INSTALLATION

şService equipment and tools
Digital thermometer
A : Temperature probe.
Fasten to a bare metal line using a tie A
band. Wrap with shop towel.
B : Cable. B C
C : Digital thermometer.

3) DISPLAY MONITOR TACHOMETER

The display monitor tachometer is accurate
enough for test work.
20 30

10 20
40
10

5 30
0 mph
0 50
km/h

6 -56
4. HYDRAULIC OIL WARM UP PROCEDURE
1) Install temperature reader(See
temperature reader installation procedure in
this group).
2) Run engine at high idle.
3) Hold a hydraulic function over relief to heat
the oil.
4) Periodically cycle all hydraulic functions to
distribute warm oil.
5) Heat oil to test specification(Approx 50Ɓ
C).

6 -57
5. MAIN HYDRAULIC PUMP FLOW TEST
ş SPECIFICATION
Oil temperature 65Ź6ƁC(150Ź10Ɓ F)
Engine speed 2200Ź25rpm
Test pressure 220Ź10bar(3190psi)
Maximum pump flow 86ֻ/min(22.7gpm)
ş FLOW METER GAUGE AND TOOL
Gauge 0~35MPa(0~350bar, 0~5000psi)
Temperature reader
1) Make test connections.
2) Install temperature reader.(See
temperature reader installation procedure in
this group.)
3) Heat hydraulic oil to specifications.(See
hydraulic oil warm up procedure in this
group.)
4) Run engine at test specifications.
5) Close flow meter loading valve to increase
pressure to test specifications.
To MCV
6) Read flow meter.
7) If flow is below specifications, check suction
line and suction pressure for abnormality
before removing pump.

6 -58
6. LOADER SYSTEM AND PORT RELIEF
VALVE PRESSURE TEST
ş SPECIFICATION
Oil temperature(45~55Ɓ
C)

Relief valve Engine speed Relief pressure

D U
220Ź5kg/cm2
System(M) High
(3130Ź70psi)

240Ź5kg/cm2 R
Boom
Low
raise(U) (3410Ź70psi)

Bucket 240Ź5kg/cm2
Low
rollback(R) (3410Ź70psi)

Bucket 240Ź5kg/cm2
Low
dump(D) (3410Ź70psi)

ş Gauge and tool

M
Gauge 0~35MPa(0~350bar, 0~5000psi)
D : Bucket dump relief valve
M : System(Main) relief valve
R : Bucket rollback relief valve
U : Boom raise relief valve
1) Install pressure gauge to block(A) in pump
delivery line.
2) Install temperature reader.(See
temperature reader installation procedure in
this group.) A
3) Heat hydraulic oil to specifications.(See
hydraulic oil warm up procedure in this
group.)
4) To check the system relief valve(M), run Block(Rear frame mounting)
engine at high idle. Lower boom to
bottomed position.
Slowly activate boom down function while
watching pressure gauge. If pressure is not
to specification, loosen lock nut on system
relief valve(M) and adjust to specification.

6 -59
Ɠ Do not adjust the system relief valve
above 250kg/cm2 (3560psi). Damage to
the pump will result from excessive
pressure settings.
5) To check the bucket dump, bucket rollback,
and boom raise, adjust the system relief
valve to 250kg/cm2 (3560psi).
Run engine to maintain 800~850rpm when
hydraulic function is activated over relief.
Activate the function to be checked with the
cylinder bottomed. Read the pressure
gauge.
If pressure is not to specification cycle relief
valve over relief 10 times to flush.
Read pressure gauge again. Turn screw
to adjust valve to specification.
Ɠ Do not work machine with system relief
adjusted above specification or
structural damage may occur.
6) Adjust system relief valve to specification.

6 -60
7. HYDRAULIC SYSTEM RESTRICTION TEST
ş SPECIFICATION
Oil temperature 65Ź6Ɓ C(150Ź10Ɓ F)
Engine speed High idle
Maximum pressure at steering(Orbitrol)
valve 2MPa(20bar, 285psi)
Maximum pressure at main control valve
1MPa(10bar, 145psi)
ş GAUGE AND TOOL
Gauge 0~7MPa(0~70bar, 0~1000psi) 2EA
This test will check for restrictions in the
hydraulic system which can cause
overheating of hydraulic oil.
1) Install temperature reader.(See temperature T
reader installation procedure in this group.)
2) Heat hydraulic oil to specifications.(See
hydraulic oil warm up procedure in this
group.)
3) Connect gauge to steering unit.
4) Connect fitting and gauge to main control
valve.
Do not operate steering or loader T port
functions or test gauge may be
damaged.
5) Run engine at specification and read P

pressure gauges.
If pressure is more than specification at the
main control valve, check for a kinked,
dented or obstructed hydraulic line. Check
main control valve for a binding spool. Main control valve

If pressure is more than specification at the

block, inspect neutral condition of the
steering valve and priority valve for a stuck
spool. Make sure orifice plugs are installed
in ends of priority valve spool.
Check for plugged orifice in priority valve LS
port and dynamic signal orifice on the spool
of priority valve.

6 -61
8. LOADER CYLINDER DRIFT TEST
A
ş SPECIFICATION
Oil temperature 40Ź6Ɓ
C(100Ź10Ɓ
F)
Boom horizontal
Bucket horizontal
Bucket unloaded
B
Item Standard value
Retraction of boom
40mm A : Retraction of bucket cylinder rod
cylinder rod
B : Retraction of boom cylinder rod
Retraction of bucket
20mm
cylinder rod

ş GAUGE AND TOOL

Stop watch
Temperature reader
Put the safety lock lever in the lock
position.
Do not go under the work equipment.
1) Set the boom and bucket horizontal, then
stop the engine.
2) Stop the engine, wait for 5 minutes, then
start measuring.
3) Measure the amount the boom and bucket
cylinder rods retract during 15 minutes.

6 -62
9. BOOM AND BUCKET CYLINDER LEAKAGE
TEST
ş SPECIFICATION
Oil temperature 40Ź6Ɓ C(100Ź10Ɓ
F)
Engine speed Low idle
Maximum leakage 12cc/10min
ş GAUGE AND TOOL
Temperature reader
Stop watch
Measuring container
1) Fasten temperature sensor to head end
port of cylinder to be tested. Cover sensor
with a shop towel.
2) Heat hydraulic oil to specifications.(See
hydraulic oil warm up procedure in this
group.)
Never work under raised equipment
unless it is supported with a hoist or
support stands.
3) Full extend the cylinder to be tested. If
testing the boom cylinders, restrain boom in
the fully raised position using a hoist or a
stand.
Ɠ Check cylinders for leakage in the fully
extended position only. In the retracted
position contacts the end of the cylinder
and seals off piston seal leakage.
4) Remove and plug cylinder rod end hose or
line.
5) Run engine at low idle. Activate control
lever to extend cylinder for 1 minute over
relief while measuring leakage for open
port.
If leakage is within specification, excessive
cylinder drift is caused by leakage in the
main control valve or circuit relief valve.

6 -63
10. PILOT CONTROL VALVE PRESSURE TEST
ş SPECIFICATION
Oil temperature 40Ź6Ɓ C(100Ź10Ɓ F)
Engine speed Low idle
Begin metering 1/4" of lever travel
Pressure in detent :
Boom float detent 1.38MPa(13.8bar)
Pressure at feel positionƕ:
Boom power down 13.4~13.8bar
Boom raise 13.4~17.2bar
Bucket rollback 13.4~17.2bar
Bucket dump 13.4~17.2bar
ş GAUGE AND TOOL T
P

Gauge 0~7MPa(0~70bar, 0~1000psi)

ƕ As the control lever is moved from neutral,
the pilot pressure will suddenly jump up to
approximately 5.8bar at 1/4in travel. The
pressure should then increase smoothly to
the specification at the FEEL position(or 3/4
A
lever travel), and then jump up about 315psi
as the lever is moved into detent.
This test will determine if adequate pilot
pressure is available to move the loader
control valve spools.
Ɠ The FEEL position is when lever is Block(Rear frame mounting)
moved to feel the ramp of the detent
before lever passes into detent position.
1) Lower boom to ground.
2) Connect gauge to the pilot pressure port(A)
of function to be checked.
3) Install temperature reader.(See
temperature reader installation procedure in
this group.)
4) Heat hydraulic oil to specification.(See
hydraulic oil warm up procedure in this
group.)

6 -64
5) Run engine at specification. Activate
function to be checked and record pressure
reading.
Ɠ If boom raise or bucket rollback FEEL
positions are not operation due to boom
or bucket position, plug boom float
detent wires into bucket leveler solenoid
or boom height kickout solenoid. This
will provide a feel position on the
control lever.

6 -65
11. PILOT OIL SUPPLY UNIT PRESSURE TEST
ş SPECIFICATION
Oil temperature 40Ź6Ɓ C(100Ź10Ɓ F)
Engine speed Low idle and stop
Pilot pressure setting 30~35bar(430~500psi)
Relief valve setting pressure
45bar
Accumulator precharging pressure
16bar
ş GAUGE AND TOOL
Gauge 0~7MPa(0~70bar, 0~1000psi)
The pilot supply unit consist of the pressure
reducing valve, the relief valve and an
accumulator. This regulates pressure to
the pilot control circuit.
1) Connect gauge to test port(A) on the block.
A
2) Install temperature reader.(See
temperature reader installation procedure in
this group.)
3) Heat hydraulic oil to specification.(See
hydraulic oil warm up procedure in this
group.)
4) Run engine at low idle for 1 minute and Block(Rear frame mounting)
stop engine, wait for 5 minutes. Then start
measuring.
5) If pressure in not within specifications,
replace valve. The valve is staked and
should not be adjusted.

6 -66
12. CYCLE TIME TEST
ş SPECIFICATION
Oil temperature 65Ź6Ɓ C(150Ź10Ɓ
F)
Engine speed High idle

Function Operating conditions Maximum cycle time(Seconds)

Boom raise Bucket flat on ground to full height 5.6

Boom lower(Float) Full height to ground level 2.8
Bucket dump Boom at full height 1.0
Bucket rollback Boom at full height 1.4
Steering(Number of turns) Frame stop to stop 1.5(4.3 turns)

Hydraulic pump performance cycle time.

Function Operating conditions Maximum cycle time(Seconds)

Bucket flat on ground to full height
Boom raise 7.0
while holding steering over relief

6 -67
13. HYDRAULIC OIL FILTER INSPECTION
PROCEDURE
1) Lower the bucket to the ground, stop the
1
engine, move the control lever back and
2
forth several times, and clean all over the
upper surface of the hydraulic oil tank.
3
2) Remove the bolts(1) and take out the filter 4
case cover(3) and O-ring(4).
3) Remove the spring(5) and bypass valve(6). 5

4) Remove the filter element(7) from the tank. 6

5) Check the element and the filter case
bottom for debris. Excessive amounts of
brass and steel particles can indicate a 7
failed hydraulic pump or a pump failure in
process. A rubber type of material can
indicated cylinder packing or other packing
failure.
Ɠ The hydraulic oil filter in the filter case of
the hydraulic oil tank should be
replaced every 250 operating hours(For
the first replacement, at 50 hours) or
more often. When the filter element is
replaced, please keep as follows.
(1) Clean the inside of the filter case.
(2) Place new element in the proper positions
inside the filter case.
(3) Install the bypass valve and spring.
Make sure the element stand upright, and
check for complete contact of the element
bottom with the filter case bottom.
(4) Install the O-ring and filter case covers.
Tighten them with bolt. Replace the O-
ring with new one if damaged.

6 -68