D8R TRACK-TYPE TRACTOR 9EM00001-UP (MACHINE) POWERED BY 3406C E...

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Product:  TRACK-TYPE TRACTOR 
Model:  D8R TRACK-TYPE TRACTOR 9EM 
Configuration: D8R TRACK-TYPE TRACTOR 9EM00001-UP (MACHINE) POWERED BY 3406C Engine 

Testing and Adjusting

D8R Track-Type Tractor Hydraulic System
Media Number -SENR8329-05 Publication Date -01/10/2013 Date Updated -08/08/2018

i05494710

Testing and Adjusting - Implement and Steering Hydraulic

System Testing and Adjusting
SMCS - 5050-036

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine can cause injury to persons on or

near the machine.

Prevent possible injury by performing the procedure that follows before

working on the machine.

Move the machine to a smooth horizontal location. Move away from

working machines and personnel and lower the buckets or implements
(loader and backhoe) and stabilizers to the ground.

Permit only one operator on the machine. Keep all other personnel away
from machine or in view of the operator.

Engage the parking brake. Stop the engine.

Move the hydraulic control levers to all positions to release the pressure
in the hydraulic system.

Procedure

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When you are defining a hydraulic system problem, do the procedures that follow. First, do Visual
Checks. If the problem has not been identified, do Operation Checks. If the problem is not
understood, do the Instrument Tests. The procedure helps identify hydraulic system problems. When
the problem is identified, go to the Troubleshooting Section. The Troubleshooting Section lists the
probable causes of a known problem. Since there may be more than one cause for a problem, the
Troubleshooting Section may suggest specific inspections or instrument tests be done. The
inspections and the tests identify the most probable cause of the problem.

During a diagnosis of the hydraulic system, remember that correct oil flow and pressure are necessary
for correct operation. The maximum output of the pump increases with an increase in engine speed
and decreases when the engine speed is decreased. Oil pressure is caused by resistance to the flow of
oil.

In order to perform the tests, use the following hardware: 1U-5796 Pressure Differential Gauge
Group, 6V-4161 Hydraulic Testing Group, stopwatch, magnet, thermometer and ruler. Use the tools
to perform the following tests.

1. Check the pump pressure settings for the implement circuit and the steering circuit. Settings
that are too low cause a decrease in the implement operation and the steering characteristics of
the machine. Settings that are too high can cause a decrease in the life of the hoses and the
components. Also, settings that are too high can cause engine overheating. Finally, settings that
are too high can cause the engine to lug.

2. Check the Drift rates in the implements. Circuit drift can be caused by the following problems:
leakage past the cylinder pistons, leakage past the cylinder piston bypass valves, leakage past
the control valve spools, leak past the load check valves, leakage past the makeup valves and
leakage in the quick-drop valve. Excessive drift can be caused by a problem with any one or
any combination of components.

3. Check the cycle times in the implement circuits. The cycle times that are greater than shown
can be caused by the following problems: leakage, valve stem displacement, pump wear and
pump speed. If the basic operation checks indicate excessive circuit leakage, the pressure tests
are needed to determine the problem.

4. Perform the steering operation checks. The steering turn diameter check and the sprocket speed
check give a good indication of the steering circuit problem.

Visual Checks
A visual inspection of the hydraulic system is the first step when a diagnosis of a problem is made.
Stop the engine. Lower the bulldozer and the ripper to the ground. In order to remove the tank filler
cap, slowly turn the filler cap until the cap is loose. If the oil comes out of the purge hole, then allow
the pressure to lower before the filler cap is removed. Make the following inspections:

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Do not check for leaks with your hands. Pin hole (very small) leaks can
result in a high velocity oil stream that will be invisible close to the hose.
This oil can penetrate the skin and cause personal injury. Use
cardboard or paper to locate pin hole leaks.

1. Check tank oil level.

2. Check all implement and steering oil line connections for damage and leaks.

3. Follow all implement and steering oil lines from the implement connections to valve
connections. Check the lines and connections for damage and leaks.

4. Check the control valves for leaks.

5. Check the pumps and connections for damage and leaks.

6. Follow the pump lines to the tank and valves. Check the lines and the tank for damage and
leaks.

7. Look for air in the oil that is in the tank. Check the oil immediately after the machine has
stopped. Use a clear bottle or a clear container in order to get a sample of the oil. A milky
appearance indicates air or water in the oil. Look for air bubbles in the oil that is in the bottle.

8. Remove the filter elements and look for particles that were removed from the oil by the filter
element. A magnet separates ferrous particles from nonferrous particles.

9. Inspect the control linkage for damaged components.

Troubleshooting
Problem Checklist

Problem List of Problems that are Common to Both the Steering System and the
Implement System

1. The temperature of the oil is too hot.

2. The pump or the pumps make unusual noises. The machine does not turn smoothly or the
implement cylinders do not move smoothly.

3. There is a large amount of air in the oil.

4. There is a loss of oil from the hydraulic system.

Hydraulic Steering Pump and System Problem List

1. There is a pause before the machine starts to steer.

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2. The steering speed is slow in both directions. The oil output of steering pump is low.

3. The steering speed is slow in one direction. The oil output of steering pump is low in one
direction.

4. The machine has low turning force in both directions. The oil output pressure of the steering
pump is low in both directions.

5. The machine has low turning force in one direction. The pressure output of the steering pump is
low in one direction.

6. There is no steering in both directions.

7. The pump remains at neutral in one direction. There is no steering in one direction.

8. Steering pump pressures in NEUTRAL are too high or too low.

9. There is a step in steering speed or steering modulation is poor.

10. Machine steers in the wrong direction.

11. Steering is jerky or unstable.

12. The steering improves when the implement hydraulics are used.

13. Machine turns when the steering tiller is returned to NEUTRAL.

14. There is no charge pump pressure or flow.

Implement Pump and System Problem List

1. Response of one implement is slow.

2. All implement cycle times or speeds are slow.

3. The implement droops when the control lever is moved from HOLD to LIFT.

4. There is too much implement drift.

5. All implement circuits are unstable.

6. The bulldozer tilt is too fast or too slow. The ripper lift and the ripper tip are too fast or too
slow.

7. Any implement moves with the control lever in HOLD position.

8. When the blade is lowered to the ground, there is excessive pause time at the ground line.

9. The implement surges when the implement is first activated.

10. The effort that is needed in order to move the control lever is too high.

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11. The response of the implement is too fast.

12. The pump does not return to standby pressure when the implement lever is returned to neutral.

13. Too little lever travel before the bulldozer quick-drop valve is activated.

14. Too much lever travel before the bulldozer quick-drop valve is activated.

15. The bulldozer quick-drop valve is not working properly.

16. The ripper does not function properly.

17. Weak hydraulics (low pressure)

List of Problems that are Common to Both the Steering System and the
Implement System

Problem 1: The temperature of the oil is too hot.

Probable Cause:

1. The oil cooler core is plugged or there is low air flow over the core.

2. The viscosity of the oil is wrong.

3. The oil level is low.

4. Oil aeration

5. The pressure setting on the cooler bypass valve is faulty and the valve is providing low flow to
the cooler.

6. Outside air temperature is too hot.

7. The implement control valve stem is partially shifted.

8. The settings on the steering pump crossover relief/makeup valve are too low.

9. The setting on the implement system main relief valve is too low.

10. The pressure cutoff setting for the steering pump is too high.

11. The pressure cutoff setting for the implement pump is too high.

12. The setting for the charge pump relief valve is too high.

13. There is a restriction in an oil passage.

14. The setting for the implement pump margin pressure is too high.

15. The implement pump has wear. The steering pump has wear. The steering motor has wear.

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Problem 2: The pump or the pumps make unusual noises. The machine does not turn smoothly.
The implement cylinders do not move smoothly.

Problem Checklist

1. The viscosity of the oil is wrong.

2. The steering pump has too much wear. The steering motor has too much wear.

3. The implement pump has too much wear.

4. The oil level is low.

5. Oil aeration from a loose connection or restriction on the inlet side of either the charge pump or
the implement pump.

6. The cylinders and lines are not properly purged of air.

7. There is either a porous weld or a broken baffle in the hydraulic tank.

Problem 3: There is a large amount of air in the oil.

Probable Cause:

1. There is a leak in the oil line from the tank to the implement pump or the charge pump.

2. There was a failure to purge the air from the hydraulic system.

3. The main implement relief valve is unstable.

4. The oil level is too low.

5. There is a broken baffle in the hydraulic tank.

Problem 4: There is a loss of oil from the hydraulic system.

Probable Cause:

1. There is leakage through a hole in a hydraulic hose or fitting.

2. Leakage past the cylinder rod seals.

3. There is leakage past the seal on the steering pump shaft.

4. There is leakage past the implement pump shaft seal.

5. There is leakage past the steering motor shaft seal.

Hydraulic Steering Pump and System Problem List

Problem 1: There is a pause before the machine starts to steer.

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Probable Cause:

1. The hydraulic oil is too thick or the type of oil is incorrect.

2. The connection from the tiller handle to the pilot valve is improperly adjusted.

3. The pilot valve is improperly adjusted or the pilot valve is faulty.

4. Charge pressure or flow is low.

5. The steering pump controls are faulty.

6. The orifice in the pump control is partially plugged.

7. The neutral setting for the steering pump is improperly adjusted.

Problem 2: The Steering speed is slow in both directions. Oil output of steering pump is low.

Probable Cause:

1. The connection from the tiller handle to the pilot valve is improperly adjusted.

2. There is low pilot pressure due to an improperly adjusted pilot valve.

3. There is a blocked pressure source to the pilot valve or a restricted pressure source to the pilot
valve.

4. Charge pressure or flow is low.

5. The steering pump controls are faulty.

6. The setting for the pump cutoff pressure is low.

7. The pump has failed or the pump has wear. The motor has failed or the motor has wear.

8. There is a spool that is stuck in the pilot valve.

9. There is a pilot spool that is stuck in the steering pump.

Problem 3: Steering speed is slow in one direction. The oil output of steering pump is low in one
direction.

Probable Cause:

1. The connection from the tiller handle to the pilot valve is improperly adjusted.

2. There is low pilot pressure due to an improperly adjusted pilot valve.

3. The flushing valve is faulty or the valve is stuck open.

4. Steering pump control is improperly adjusted or the control is faulty.

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Problem 4: The machine has low turning force in both directions. The output pressure of the
steering pump is low in both directions.

Probable Cause:

1. The cutoff pressure setting for the pump is too low.

2. Both crossover relief/makeup valve pressure settings are low or the valves are faulty.

3. Charge pressure is too low.

4. The pump or the motor has too much wear.

Problem 5: The machine has low turning force in one direction. The pressure output of the
steering pump is low in one direction.

Probable Cause:

1. One crossover relief/makeup valve pressure setting is low or the valve is faulty.

2. The flushing valve is stuck open or there is high leakage through the valve.

3. There is high wear or leakage in the pump or the motor.

Problem 6: The machine will not turn in either direction.

Probable Cause:

1. Low charge pump pressure or flow.

2. There is no pilot pressure that is caused by the following causes:

a. The tiller handle is not connected to the pilot valve or the linkage is out of adjustment.

b. There is no supply pressure to the pilot valve due to a blocked hose or low pilot supply
pressure.

c. The pilot valve is faulty or improperly adjusted.

d. Pilot valve supply pressure is low due to high leakage through the solenoid valve in the
ripper diverter valve.

3. The pump cutoff valve is faulty.

4. The pump or the motor has failed.

5. The pump or the motor is loose. The pump or the motor has backed out of the drive splines.

6. The parking brake is not releasing. The problem is caused by the following causes:

a. The linkage is not properly adjusted.

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b. The spool in the brake valve is stuck.

c. There is internal leakage in the brake valve.

Problem 7: The pump remains at neutral in one direction. The machine does not turn in one
direction.

Probable Cause:

1. The linkage from the tiller handle to the pilot valve is not properly adjusted.

2. There is no pilot pressure from the pilot valve due to a blocked hose.

3. The controls in the steering pump are faulty.

4. The flushing valve in the motor is stuck open.

5. The pump null setting is improperly adjusted.

6. The pilot valve is faulty or improperly adjusted.

7. There is high leakage in the steering pump controls.

Problem 8: Steering pump pressures in NEUTRAL are too high or too low.

Probable Cause:

1. The pressure setting for the charge relief valve is too high or too low.

2. The setting for the cold oil bypass relief valve is low.

3. There is high leakage through the pilot valve due to wear.

4. There is high leakage through the solenoid valve in the ripper diverter valve.

Problem 9: There is a step in steering speed or steering modulation is poor.

Probable Cause:

1. The hydraulic oil is too thick or the oil is the wrong type. Warm the oil to operating
temperature.

2. The pilot valve is not adjusted properly.

3. The pilot valve is faulty.

4. There is a restriction in the hose to the pilot valve.

5. There is a restriction in the drain hose for the pilot valve.

6. There is a worn bearing in the linkage.

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7. The pump control is faulty or the control needs adjustment.

Problem 10: Machine steers in the wrong direction.

Probable Cause:

1. The pilot lines are connected incorrectly at the pilot valve or at the pump.

2. The high-pressure hoses are connected incorrectly between the pump and the motor.

Problem 11: Steering is jerky or unstable.

Probable Cause:

1. There is an interaction between the pump cutoff valve and the crossover relief/makeup valves.

2. The hydraulic oil is too thick or the oil is the wrong type. Warm oil to operating temperature.

3. The charge relief valve is unstable.

Problem 12: Machine steers correctly only when implement hydraulics are used.

Probable Cause:

1. The charge pump has wear that is causing low charge flow.

2. The setting on the pressure reducing valve for the implement pump is too high. The valve will
not shift until the implement pump pressure is high enough to shift the spool.

3. There is high leakage in the high-pressure steering loop.

4. The pilot valve is faulty.

5. The low pressure standby pressure for the implement pump is set too low.

Problem 13: The machine continues to turn when the steering tiller is returned to NEUTRAL.

Probable Cause:

1. The pilot valve is not adjusted properly. The linkage is loose or there is not enough deadband.

2. Adjustment of mechanical zero position in steering pump is not correct.

3. Adjustment of hydraulic zero position at neutral is not correct.

4. The pilot valve is not adjusted properly. There is high pilot pressure in one direction in neutral.

5. The tiller linkage is not adjusted properly or the linkage is loose.

6. The pump control is faulty. The problem is caused by the following causes:

a. There is a broken spring.

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b. The pilot spool is sticking.

7. The spool is sticking in the pilot valve.

8. The pump has failed.

Problem 14: Low charge pump pressure or flow.

Probable Cause:

1. The hydraulic oil tank level is too low.

2. The pump inlet or The suction line is blocked or crushed.

3. The charge pump has failed or the pump is worn.

4. The cold oil bypass relief valve that is located in the pressure control valve is faulty or the valve
setting is too low.

5. The charge pressure relief valve in the steering pump is faulty or the valve setting is too low.

6. There is high leakage through the pilot valve.

7. There is high leakage through the solenoid valve on the ripper diverter valve.

Implement Pump and System Problem List

Problem 1: Response of one implement is too slow.

Probable Cause:

1. The implement valve spool is not fully shifted.

2. The lever linkage or lever travel is restricted.

3. The wrong control valve for the implement is installed in the valve bank.

4. The control valve is faulty.

Problem 2: All implement cycle times are too slow.

Probable Cause:

1. The air purge valve on the implement pump controls is open.

2. The margin pressure setting is too low.

3. There is a blockage or a leakage in the signal network. The problem is caused by the following
causes:

a. The signal line is plugged or the line is not hooked up.

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b. The shuttle valve is stuck open or the valve has a failed seal.

c. The flow control sleeve that is behind the flow control spring has a failed seal.

d. The plug that is in the end of the control valve spool has a failed seal.

4. The pump control is faulty.

5. The pump is not at full stroke.

6. The diameter of the hoses or the fittings is incorrect.

Problem 3: The implement droops when the control lever is moved from HOLD to LIFT.

Probable Cause:

1. The load check valve is not closing. The problem is caused by the following causes:

a. The spring is weak or broken.

b. The valve has dirt or debris.

c. There is a faulty seat.

Problem 4: There is too much implement drift.

Probable Cause:

1. The valve spool in the control valve is not correctly centered. The problem is caused by the
following causes:

a. There is a broken spring.

b. There is a sticky valve spool.

c. There is a misadjusted linkage.

2. There is leakage around the seals on the piston.

3. There is leakage past the makeup valve or the makeup valve seals have failed.

4. The quick-drop valve or the end stroke bypass valves may be leaking.

5. The control valve has too much wear.

Problem 5: All implement circuits are unstable.

Probable Cause:

1. Hydraulic oil is too thick or the oil is the wrong type. Warm oil to operating temperature.

2. The hydraulic pump is faulty.

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3. Air in oil or air is trapped in signal line.

Problem 6: Implement cycle times are too fast.

Probable Cause:

1. The flow control valves failed or there is an incorrect spool.

Problem 7: Any implement moves with the control lever in the HOLD position.

Probable Cause:

1. The control valve and the valve spool have a large amount of wear.

2. The seals in the cylinder piston have failed or the seals are worn.

3. The load check valve is faulty.

Problem 8: Excessive pause time at ground line when powering blade down.

Probable Cause:

1. The quick-drop valve is not operating correctly.

2. The makeup valve is stuck open.

3. There is a restriction in a hose.

Problem 9: The implement surges when the implement is first activated.

Probable Cause:

1. The slots in the control stem are not machined correctly.

Problem 10: The effort that is needed in order to move the control lever is too high.

Probable Cause:

1. The lever linkage is restricted or the linkage has interference.

2. The wrong control valve is installed in the valve bank.

3. The flow control spool in the control valve is sticking or defective.

Problem 11: The response of the implement is too fast.

Probable Cause:

1. The wrong control valve is installed in the valve bank.

2. The control valve is defective.

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Problem 12: The pump does not return to standby pressure after the implement is used.

Probable Cause:

1. The control lever has interference and the lever does not return to HOLD position.

2. The hydraulic pump or the compensator valve is defective.

Problem 13: There is too little lever travel before the bulldozer quick-drop valve is activated.

Probable Cause:

1. There is the wrong number of shims under the springs in quick-drop valve.

2. There is the wrong diameter of the orifice sleeve in the quick-drop valve.

3. There is a weak spring in the quick-drop valve.

Problem 14: There is too Much lever travel before the bulldozer quick-drop valve is activated.

Probable Cause:

1. There is a missing or a defective orifice sleeve in the quick-drop valve.

2. There is a wrong spring or too many shims in the quick-drop valve.

3. The orifices or the passages in the quick-drop spool are plugged with debris.

4. The quick-drop spool is stuck or jammed with debris.

Problem 15: The quick-drop valve is not working properly.

Probable Cause:

1. The orifice sleeve is stuck.

2. The quick-drop spool is stuck.

3. The spring force is weak or there is a broken spring.

4. The lower linkage is not adjusted properly.

5. The plug in the quick-drop spool is loose or missing.

Problem 16: The ripper does not function properly.

Probable Cause:

1. There is no pilot pressure to the ripper diverter valve.

2. There is no electrical current at the solenoid valve on the ripper diverter valve.

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3. The solenoid valve on the ripper diverter valve is defective.

4. The spool in the ripper diverter valve is stuck.

5. The main spool is stuck or damaged.

6. There is a broken main spool spring.

Problem 17: There is weak hydraulics.

Probable Cause:

1. The air purge valve on the implement pump controls is open.

2. The signal line is not connected or plugged.

3. There is a stuck pressure resolver ball.

4. The end pressure resolver is not drained to the tank.

5. The pump cutoff pressure setting is low.

6. There is a broken load sensing spring or pressure cutoff spring.

7. There is an improperly adjusted linkage.

8. The pump is worn out.

9. There is leakage in the system.

10. The makeup valve is stuck open.

11. The main relief valve pressure setting is wrong or the relief valve is defective.

Implement Operation Checks

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine can cause injury to persons on or

near the machine.

Prevent possible injury by performing the procedure that follows before

working on the machine.

Move the machine to a smooth horizontal location. Move away from

working machines and personnel and lower the buckets or implements
(loader and backhoe) and stabilizers to the ground.

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Permit only one operator on the machine. Keep all other personnel away
from machine or in view of the operator.

Engage the parking brake. Stop the engine.

Move the hydraulic control levers to all positions to release the pressure
in the hydraulic system.

The operation checks can be used to find leakage in the system. Also, the tests can be used to find a
bad valve or a bad pump. The speed of the rod movement can be used in order to check the condition
of the cylinders and the condition of the pump.

Raise and lower the bulldozer and the ripper several times. Operate the tilt control valve until the tilt
cylinder has been fully extended and retracted several times.

1. Watch the cylinders as the cylinders are extended and retracted. Movement must be smooth and
regular.

2. Listen for noise from the pump.

3. Allow the implement cylinders to travel full stroke in each direction.

4. Put each control valve in the HOLD position while the implement is off the ground. Watch for
excessive cylinder rod drift.

Cylinder Speed Tests

The oil in the system must be SAE 10. Also, the oil must be at a temperature of 65° ± 3°C
(150° ± 5°F) in order to get correct results. All speed tests are made with the engine rpm at HIGH
IDLE.

The speeds that are the same as the speeds shown in the chart, give an indication that the circuit
operation is normal.

Table 1
Bulldozer Blade Bulldozer Tilt Cylinder Speed Test Time in
Seconds
SU-BLADE or U- Full tilt left to full tilt right or full tilt right to full tilt 1.7 to 2.0
BLADE left
A Full tilt right to full tilt left only 1.0 to 1.2

Table 2
Bulldozer Blade Bulldozer Lift Cylinder Speed Test Time In Seconds
All Blades Ground to full up. 2.7 to 3.0

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Full up to ground (Quick-drop) .9 to 1.2

Pause at ground (Quick-drop). 1.4 to 1.7

Table 3
Ripper Cylinders Speed Test Speed In Seconds
Full down to full up. 3.6 to 4.0
Full shank in to full shank out (Retract Cylinder). 4.2 to 4.9

If the cylinder speeds are not correct use the following steps:

1. If only one of the cylinder speeds is slow, see the Implement Pump and System Problem List,
Problem 1.

2. If more than one of the cylinder speeds are slow, see Implement Pump and System Problem
List, Problem 2, Problem 6, or Problem 11.

Bulldozer Lift Cylinders Drift Tests

The drift rates change with the different conditions of the hydraulic components. Before measuring
drift on the cylinder rod, the cylinders must be extended and retracted at least five times. Measure the
rod drift by using the following procedure:

1. Check the hydraulic oil temperature.

2. Lift the bulldozer until the cutting edge is approximately 300 mm (12 inch) off the ground.
With the lift control lever in the HOLD position, stop the engine.

3. Measure the extension of the lift cylinder rods from the lift cylinders. Record the distance that
was measured.

4. Record the distance and check the time that the cylinders extend. Compare the readings with the
chart.

Note: The drift distance in the chart is for new machines.

Table 4
Bulldozer Lift Cylinder Drift
Oil Temperature 28° to 48°C 49° to 68°C 69° to 88°C
(83° to 118°F) (120° to 155°F) (156° to 190°F)
Must not move more than 5 minutes 2.7 minutes 1.7 minutes
38 mm (1.5 inch)

Note: If excessive cylinder drift is noted, run the following tests in order to determine the cause.

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Tests

1. Raise the front of the machine off the ground by lowering the bulldozer on level ground. Put the
control lever in the HOLD position. Shut off the engine and watch the lift cylinder rods for
movement.

2. Raise the front of the machine off the ground by lowering the bulldozer on level ground. Shut
off the engine. Hold the lift control lever in the LOWER position. Watch the lift cylinder rods
for movement.

3. Raise the bulldozer off the ground. Put the control lever in the HOLD position. Shut off the
engine and watch the lift cylinder rods for movement.

4. Raise the bulldozer off the ground. Shut off the engine. Hold the lift control lever in the RAISE
position. Watch the lift cylinder rods for movement.

Table 5
Test Results Most Probable Causes
Drifting occurs in Tests No. 1 and The lift circuit makeup valve (head ends) is leaking.
No. 2.
Drifting occurs in Tests No. 1 and Leakage between lift valve spool and body.
No. 3.
Drifting occurs in Tests No. 1, No. Leakage between pistons and cylinders. Bad piston valves in
2, No. 3 and No. 4. cylinders. Quick-drop valve leaks.
Drifting occurs in Tests No. 2 and Lift circuit load check valve or flow control valve is leaking.
No. 4.

Note: Remember that an O-ring seal failure in the circuit has the same effect as a major component
failure.

Bulldozer Tilt Cylinder Drift Tests

Measure the tilt cylinder rod drift by using the following procedure:

1. Check the hydraulic oil temperature.

2. Fully retract the tilt cylinder.

3. Lower the bulldozer in order to lift the front idlers off the ground. When the lift/tilt control
valve is in HOLD, stop the engine.

4. Measure the distance and check the time that the cylinders extend. Compare the values with the
chart.

Note: The drift distance in the chart is for new machines.

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Table 6
Bulldozer Tilt Cylinder Drift
Oil Temperature 28° to 48°C 49° to 68°C 69° to 88°C
(83° to 118°F) (120° to 155°F) (156° to 190°F)
Must not move more than 5 minutes 2.7 minutes 1.7 minutes
11 mm (.43 inch)

Note: If excessive cylinder drift is noted, run the following tests in order to determine the cause.

Tests

1. Put the bulldozer flat on the ground. Raise the front of the machine off the ground by lowering
the right side of the blade. Put the tilt circuit in the HOLD position. Shut off the engine and
watch the tilt cylinder rod for movement.

2. Put the bulldozer flat on the ground. Raise the front of the machine off the ground by lowering
the left side of the blade. Put the tilt circuit in the HOLD position. Shut off the engine and
watch the tilt cylinder rod for movement.

Table 7
Test Results Most Probable Causes
Drifting occurs in Tests No. 1 Leakage between piston and cylinder. Leakage between tilt
and No. 2. circuit valve spool and body.

Note: Remember that an O-ring seal failure in the circuit has the same effect as a major component
failure.

Ripper Lift Cylinders Drift Tests

Measure the ripper lift cylinder rod drift by using the following procedure:

1. Check hydraulic oil temperature.

2. Position the ripper so that the lowest point on the ripper is approximately 300 mm (12 inch)
above ground. Position the tip cylinders at midstroke.

3. Measure the distance and check the time that the cylinders extend. Compare the values with the
chart.

Note: The drift distance in the chart is for new machines.

Table 8
Ripper Lift Cylinder Drift
Oil Temperature 28° to 48°C 49° to 68°C 69° to 88°C
(83° to 118°F) (120° to 155°F) (156° to 190°F)

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Must not move more than 5 minutes 2.7 minutes 1.7 minutes
10 mm (.39 inch)

Note: If excessive cylinder drift is noted, run the following tests in order to determine the cause.

Tests

1. Raise the rear of the machine off the ground by lowering the ripper. Put the ripper control lever
in HOLD position. Shut off the engine and watch the ripper lift cylinder rods for movement.

2. Raise the ripper off the ground. Put the control lever in HOLD position. Shut off the engine and
watch the ripper lift cylinder rods for movement.

Table 9
Test Results Most Probable Causes
Drifting occurs in Tests No. 1 Leakage between piston and cylinder. Leakage between ripper lift
and No. 2. circuit valve spool and body.
Drifting occurs in Test No. 1. Lift circuit makeup valve (head ends) leaking.

Note: Remember that an O-ring seal failure in the circuit has the same effect as a major component
failure.

Note: If excessive cylinder drift is noted in both the ripper lift cylinder and the ripper tip cylinder, the
problem may be in the ripper diverter valve.

Ripper Tip Cylinders Drift Tests

Measure the ripper tip cylinder rod drift by using the following procedure:

1. Check hydraulic oil temperature.

2. Fully retract the ripper tip cylinders and fully extend the ripper lift cylinders.

3. Measure the distance and check the time that the cylinders extend. Compare the values with the
chart.

Note: The drift distance in the chart is for new machines.

Table 10
Ripper Tip Cylinder Drift
Oil Temperature 28° to 48°C 49° to 68°C 69° to 88°C
(83° to 118°F) (120° to 155°F) (156° to 190°F)
Must not move more than 5 minutes 2.7 minutes 1.7 minutes
6.0 mm (.24 inch)

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Note: If excessive cylinder drift is noted, run the following tests in order to determine the cause.

Tests

1. Tip the ripper until the tip cylinders are fully retracted. Lower the ripper until the lift cylinders
are fully extended. Put the ripper control lever in HOLD position. Shut off the engine and watch
the ripper tip cylinder rods for movement.

2. Tip the ripper forward until the tip cylinders are fully extended. Lower the ripper until the lift
cylinders are fully extended. Put the ripper control lever in HOLD position. Shut off the engine
and watch the ripper tip cylinder rods for movement.

Table 11
Test Results Most Probable Causes
Drifting occurs in Tests No. 1 Leakage between piston and cylinder. Leakage between ripper tip
and No. 2. circuit valve spool and body.
Drifting occurs in Test No. 1. Tip circuit makeup valve (head ends) leaking.

Note: Remember that an O-ring seal failure in the circuit has the same effect as a major component
failure.

Note: If excessive cylinder drift is noted in both the ripper lift cylinder and the ripper tip cylinder, the
problem may be in the ripper diverter valve.

Steering Operation Checks

The steering operation checks indicate that the steering circuit operation is normal. The sprocket
speed and steering turn checks are the checks that give an indication of steering circuit problems.

To prevent personal injury when checks are made while the machine is
in operation, make sure only approved personnel are on the machine.
Keep other personnel off the machine and in view of the operator. Make
sure checks are done in an open area.

Steering Turn Diameter Check

1. Move the machine to a flat, dry open area. When turning the machine, check that there is a
limited amount of track slip. Make sure that the steering linkage is adjusted.

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2. Start and run the engine at HIGH IDLE. Raise all the implements to the FULL RAISE position
and return the levers to the HOLD position.

3. Release the parking brake and put the transmission in FIRST SPEED FORWARD.

4. Place the steering control handle in the full steer left position. Keep all implement controls in
the HOLD position.

5. Make a full 360 degree turn.

6. Stop the machine after the full turn. Lower all implements to the ground and stop the engine.

7. Measure distance (A) as shown. Distance (A) should be 1.2 to 1.8 m (3.9 to 5.9 ft).

8. Repeat steps 1 through 7 with the steering control handle in the FULL STEER RIGHT position.

9. If the distances measured in Steps 7 and 8 are within specification, the steering hydraulic
system is operating correctly. If the distances measured in Steps 7 and 8 are not within
specification, proceed to Step 10.

10. Do Steps 1 through 6 again with steering control handle at the FULL STEER RIGHT and the
FULL STEER LEFT positions with the bulldozer control lever held in the FULL RAISE
position.

11. Measure distance (A) as shown. Distance (A) should be 1.2 to 1.8 m (3.9 to 5.9 ft).

12. Refer to the following in order to help diagnose the steering system.

Illustration 1 g00491216
Full Turn Diameter
(A) Diameter of the turn

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Problem: The machine will not turn. The steering radius is gradual.

Possible Causes:

1. The steering linkage is disconnected or broken.

2. The pump is not connected to the pump drive or the pump drive shaft is broken.

3. The oil level in the hydraulic tank is low.

4. The steering pump or the motor has failed.

5. There is no charge or pilot pressure.

6. The parking brake is ON. The problem is caused by the following causes:

a. The linkage is misadjusted.

b. The power train oil pressure is low.

c. Internal leakage in brake valve

7. There is a mechanical problem in the drive train.

Problem: Distance (A) is too large in Steps 7 and 8, but within specification in Steps 10 and 11.

Possible Causes:

1. The implement pressure reducing valve is not shifting at the correct pressure.

2. The implement pump standby pressure is too low.

Problem: Distance (A) is too large in Steps 7, 8, 10 and 11.

Possible Causes:

1. The charge pressure is low. The problem is caused by the following causes:

a. The charge pump is defective or worn.

b. The cold oil bypass valve is defective.

c. The charge pressure relief valve is set too low.

d. There is high leakage at the motor flushing valve.

e. The steering pump or the steering motor has failed.

2. There is low pilot pressure. The problem is caused by the following causes:

a. The tiller is improperly adjusted.

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b. Improperly set pilot valves.

c. There is excessive leakage in the pilot valve.

d. There is a blocked supply line to the pilot valve.

e. There is leakage at the solenoid in the ripper diverter valve.

3. Steering pump:

a. The crossover relief/makeup valve is leaking.

b. The pump controls are misadjusted or defective.

c. The stops are incorrect or worn.

4. Steering motor:

a. The motor is worn or failed.

b. The flushing valve is defective.

Problem: Distance (A) is too large in one direction in Steps 7, 8, 10, and 11.

Possible Causes:

1. There is Low charge pressure. The problem is caused by the following causes:

a. There is high leakage at the motor flushing valve.

b. The steering pump or the steering motor has failed.

2. There is low pilot pressure. The problem is caused by the following causes:

a. The steering tiller is improperly adjusted.

b. Improperly set pilot valves.

c. There is excessive leakage on one side of the pilot valve.

d. There is a blocked pump signal line from the pilot valve.

3. Steering pump:

a. The crossover relief/makeup valve is leaking.

b. The pump controls are misadjusted or defective.

c. The pump is worn or failed.

4. Steering motor:

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a. The motor is worn or failed.

b. The flushing valve is defective.

Sprocket Speed Check

Note: The check should be used primarily in a shop area after the machine has been repaired or
rebuilt.

1. Move the machine to a flat open area. Lower the implements to the ground and stop the engine.

2. Separate the tracks and remove the final drive sprockets. Power Train Disassembly and
Assembly, senr3412.

3. Before the checks are made, make sure that the steering linkage is correctly adjusted. Also, put
a mark on both final drives.

4. Start the engine and run at HIGH IDLE.

5. Release the parking brake and move the steering control lever to the FULL STEER RIGHT
position with the transmission in NEUTRAL.

6. In order to check the pump flow through the system, use a stopwatch. Count the revolutions per
minute of the sprockets. Subtract the right sprocket speed from the left sprocket speed. Forward
rotation is positive and reverse rotation is negative. The speed difference between left sprocket
and right sprocket should be 25.75 ± 1.25 rpm.

7. To check the mechanical drag balance between left and right sprockets, add the left sprocket
speed and the right sprocket speed. The sum should be 0 ± 3.5 rpm.

8. Do steps 5, 6, and 7 again, but move the steering control lever to FULL STEER LEFT position.
Sprocket speed difference for the full steer left position should be −25.75 ± 1.25 rpm.

9. If the sprocket speeds are not within the tolerances, check the component operation. Also,
check the adjustment of the tiller handle. If Step 6 is low, check the engine speed. If Step 7 is
out of tolerance, excessive mechanical drag may be present in the differential steer unit and the
final drives.

10. If a problem had been indicated by the checks, use Diagnostic Instrument Tests to get a more
accurate indication of the location of the specific problem.

11. If the values found in Steps 6, 7, and 8 for both FULL STEER RIGHT and FULL STEER
LEFT are within specification, perform the following calculation in order to check the steering
balance: Using the values found in Step 6, add the value for FULL STEER LEFT to the value
for FULL STEER RIGHT. The value should be 0 ± 1.1 rpm.

12. If the value in Step 11 is not within specification, the machine is not steering equal right to left.
The most probable cause is that the pump is not stroking equal displacement right and left. The
problem may be caused by a misadjusted pump control or a faulty pilot control valve.

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13. When the checks, and the adjustments are complete, stop the engine. Remove all test equipment
and connect the track.

Diagnostic Instrument Tests - Implement Hydraulic System

The test is used mainly to determine the location of a problem in the implement hydraulic circuit.

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine can cause injury to persons on or

near the machine.

Prevent possible injury by performing the procedure that follows before

working on the machine.

Move the machine to a smooth horizontal location. Move away from

working machines and personnel and lower the buckets or implements
(loader and backhoe) and stabilizers to the ground.

Permit only one operator on the machine. Keep all other personnel away
from machine or in view of the operator.

Engage the parking brake. Stop the engine.

Move the hydraulic control levers to all positions to release the pressure
in the hydraulic system.

Table 12
Tools Required:
1u-5796 Pressure Differential Gauge Group
6v-3121 Multitach

1. Move the machine to a flat open area. Lower the implements to the ground and stop the engine.

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Illustration 2 g00491364
Implement Valve Group (Seat and Floor Pan Removed)
(A) Pump Discharge Pressure tap
(B) Pressure tap (signal oil)

2. Remove the seat and the floor panel. Install a 1u-5755 Hose Assembly on pressure taps (A) and
(B).

3. Connect the other ends of the hoses to the 1u-5796 Pressure Differential Gauge Group. Connect
the hose for pressure tap (A) to the tee side of the ΔP gauge. Connect the hose from pressure tap
(B) to the elbow side of the ΔP gauge.

4. Install the 8t-0861 Gauge ( 60000 kPa (8700 psi)) on the tee side of the ΔP gauge.

5. Make sure that the implement control linkage is correctly adjusted for the implement valves.

6. Install the 6v-3121 Multitach on the tachometer drive.

7. Start and run the engine at HIGH IDLE. Record the rpm. The reading should be HIGH IDLE.
Check the Vehicle Fuel Specifications (Zero T) for the most current specification for the
engine.

8. With the engine at HIGH IDLE, move the bulldozer control lever halfway between HOLD and
FULL RAISE. Record the readings on the ΔP gauge while the bulldozer is still moving up. The
reading on the ΔP gauge is margin pressure or the difference between pump discharge pressure
and signal pressure from the implement control valve.

The margin pressure should be 2100 ± 275 kPa (305 ± 40 psi). If the margin pressure is not
correct, then see the topic Compensator Valve Adjustments/Margin Pressure Adjustments for
the correct procedure to make an adjustment. If the margin pressure is adjusted, the differential
pressure should be held to 2100 ± 100 kPa (305 ± 15 psi).

9. With the engine at HIGH IDLE, move the bulldozer blade tilt lever to the maximum TILT
LEFT or TILT RIGHT position. After the cylinder has hit the end of the stroke, the implement
pump is at a stall or cutoff condition.

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Note: For machines not equipped with tilt cylinders or for machines without the bulldozer
installed, blocking plates may be used on the lift circuit hoses.

10. With the machine in the implement pump stall condition, record the following readings:

a. Pump discharge pressure (read gauge on tee side of ΔP gauge).

b. Engine rpm.

c. Pressure on the ΔP gauge.

Note: Do not hold the machine in the implement stall condition for more than 15 seconds
at a time. Wait 1 to 2 minutes before going back to the stall condition.

11. Readings from Step 10 should be the following readings:

a. 24200 ± 350 kPa (3510 ± 51 psi)

b. 30 rpm or less below the reading recorded in Step 7.

c. 350 kPa (50 psi) maximum with a maximum oil temperature of 66°C (150°F).

If all readings are with in specification, the implement hydraulic pump should be okay,
but there still could be a problem in the individual implement circuits.

12. Use the following Problems and Possible Causes to help diagnose implement system problems
based on the results of the above tests. Remove test equipment after all tests, adjustments, and
needed repairs are completed.

Problem: Reading A is too high or too low.

Possible Causes:

1. The pressure cutoff must be adjusted.

Note: If the pressure cutoff cannot be adjusted, the pump or the compensator valve has failed.

Problem: Reading A is within specification. Reading A is too low. Reading B is correct and
reading C is too high. The readings indicate a leak(s) in the signal network between the
implement control valve and the implement pump compensator valve. The leak(s) could be
caused by the following causes:

Possible Causes:

1. There is dirt or foreign material in the orifice in the signal line at the implement valve.

2. There is a ball that is stuck in the resolver network.

3. The end resolver of the signal resolver network is not drained to the tank.

4. There is air in the signal hose.

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5. The compensator valve is not adjusted correctly or the valve is defective.

6. The implement valve spool or the spool bore is badly scratched.

7. Signal line is not hooked up properly.

8. There is leakage around the implement pump air purge valve.

Problem: Reading B is not correct and reading A is correct or too low. The readings indicate
that there is excessive power used by the pump in the implement pump stall condition.

Possible Causes:

1. The setting on the main implement relief valve is too low or the valve is leaking.

2. The implement pump has failed.

3. The implement valve spool or the spool bore is badly scratched.

Implement Pump Discharge Pressure Tests

The maximum and minimum implement pump discharge pressures are known values and the
pressures can be tested. The tests are the following tests:Low Pressure Standby Test, High Pressure
Stall Test and Margin Pressure Test.

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine can cause injury to persons on or

near the machine.

Prevent possible injury by performing the procedure that follows before

working on the machine.

Move the machine to a smooth horizontal location. Move away from

working machines and personnel and lower the buckets or implements
(loader and backhoe) and stabilizers to the ground.

Permit only one operator on the machine. Keep all other personnel away
from machine or in view of the operator.

Engage the parking brake. Stop the engine.

Move the hydraulic control levers to all positions to release the pressure
in the hydraulic system.

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Low Pressure Standby Test

Table 13
Tools Required:
6v-7830 Tetragauge Gauge

1. Remove the operator seat and the floor panel from the machine.

Illustration 3 g00491364
Implement Valve Group (Seat and Floor Panel Removed)
(A) Pump Discharge Pressure tap
(B) Pressure tap (signal oil)

2. Install the tetragauge on pressure tap (A).

3. Start the engine and run at minimum rpm. Make sure that the parking brake is fully engaged.

4. Leave all controls in the HOLD position.

5. The reading on the tetragauge should be approximately 3000 kPa (435 psi). The reading is the
pump pressure output in the low pressure standby condition. If the pressure reading is below
2100 kPa (305 psi) or above 3600 kPa (520 psi), check the margin pressure setting.

6. Adjustments to the pump output should not be made based on the results of the test. If the
results are not correct, the Margin Pressure Test should be run.

High Pressure Stall Test

Table 14
Tools Required:
1u-5796 Pressure Differential Gauge Group

1. Remove the operator seat and the floorplate beneath the seat.

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2. Install one 1u-5755 Hose Assembly on pressure tap (A). Install the other hose assembly on
pressure tap (B). Connect the other ends of the hoses to 1u-5793 Pressure Differential Gauge
Group. Connect the hose from pressure tap (A) to the tee side of the ΔP gauge. Connect the
hose from pressure tap (B) to the elbow side of the ΔP gauge.

3. Install the 8t-0861 Gauge ( 60000 kPa (8700 psi)) on the tee side of the ΔP gauge.

4. Start the engine and run at HIGH IDLE.

5. With the engine at HIGH IDLE, move the bulldozer blade tilt lever to the maximum TILT
LEFT or TILT RIGHT position. After the cylinder is at the end of the stroke, the implement
pump is at the stall condition.

Note: For machines not equipped with tilt cylinders or machines without the bulldozer
installed, blocking plates may be used on the lift circuit hoses for the test.

6. The pressure reading on the 8t-0861 Gauge should be 24100 ± 450 kPa (3500 ± 65 psi). The
pressure reading on the ΔP gauge should be less than 345 kPa (50 psi) at a maximum oil
temperature of 66°C (150°F).

Note: Do not hold the machine in the implement stall condition for more than 15 seconds at a
time. Wait 1 to 2 minutes before going back to the stall condition.

7. If the maximum pressure is too high or too low, the pressure cutoff must be adjusted.

Margin Pressure Test

With the engine still at HIGH IDLE, move the bulldozer control lever to a position that is halfway
between HOLD and FULL RAISE. Record the readings on the ΔP gauge while the bulldozer is still
moving up. The reading on the ΔP gauge is margin pressure or the difference between pump
discharge pressure and signal pressure from the implement control valve. The margin pressure should
be 2100 ± 275 kPa (304 ± 40 psi). If the margin pressure is not correct, see Margin Spool Adjustment
under the topic Compensator Valve Adjustments for the correct procedure to make an adjustment. If
the margin pressure is adjusted, the differential pressure should be held to 2100 ± 100 kPa
(305 ± 15 psi).

Compensator Valve Adjustments

The compensator valve on the pump can be tested by running one of the pump discharge tests. The
high-pressure stall test tells if the pressure cutoff spool needs to be adjusted. The margin pressure test
tells if the margin spool needs to be adjusted.

Personal injury or death can result from sudden machine movement.

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Sudden movement of the machine can cause injury to persons on or

near the machine.

Prevent possible injury by performing the procedure that follows before

working on the machine.

Move the machine to a smooth horizontal location. Move away from

working machines and personnel and lower the buckets or implements
(loader and backhoe) and stabilizers to the ground.

Permit only one operator on the machine. Keep all other personnel away
from machine or in view of the operator.

Engage the parking brake. Stop the engine.

Move the hydraulic control levers to all positions to release the pressure
in the hydraulic system.

Illustration 4 g00491544
Pressure Compensator Valve
(3) Margin spool
(6) Pressure cutoff spool

Pressure Cutoff Spool Adjustment

If an adjustment to the pressure cutoff spool is required, use the following procedure:

1. Lower all implements to the ground.

2. Shut off the engine and move all of the implement control levers in order to release the system
pressure.

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3. Hold screw (4) with a hex wrench and loosen locknut (5) with a combination wrench. Turn
screw (4) counterclockwise in order to decrease the pressure setting and turn the screw
clockwise in order to increase the setting.

Note: All adjustments should be made by starting at the lower pressure setting and working
upward.

4. When the pressure setting is adjusted, hold screw (4) with a hex wrench and tighten locknut (5)
to a torque of 9 ± 1 N·m (7 ± 1 lb ft).

5. Do the High Pressure Stall Test again in order to make sure that the pressure setting is
23990 ± 515 kPa (3480 ± 75 psi).

Illustration 5 g00491586
Implement Pump Pressure Compensator Valve
(1) Screw
(2) Locknut
(3) Margin spool
(4) Screw
(5) Locknut
(6) Pressure cutoff spool

Margin Spool Adjustment

If an adjustment to the margin spool is required, do the following procedure:

1. Lower all implements to the ground.

2. Shut off the engine and move all of the control levers in order to release the system pressure.

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3. Hold screw (1) with a hex wrench and loosen locknut (2) with a combination wrench. Turn
screw (1) counterclockwise in order to decrease the pressure setting and turn the screw
clockwise in order to increase the setting.

Note: All adjustments should be made by starting at the lower pressure setting and working
upward.

4. When the pressure setting is adjusted, hold screw (1) with the hex wrench and tighten locknut
(2) to a torque of 9 ± 1 N·m (7 ± 1 lb ft).

5. Do the Margin Pressure Test again in order to make sure that the differential pressure setting is
2100 ± 100 kPa (305 ± 15 psi).

Signal Network purge Procedure (Implement)

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine can cause injury to persons on or

near the machine.

Prevent possible injury by performing the procedure that follows before

working on the machine.

Move the machine to a smooth horizontal location. Move away from

working machines and personnel and lower the buckets or implements
(loader and backhoe) and stabilizers to the ground.

Permit only one operator on the machine. Keep all other personnel away
from machine or in view of the operator.

Engage the parking brake. Stop the engine.

Move the hydraulic control levers to all positions to release the pressure
in the hydraulic system.

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Illustration 6 g00491594
Compensator Valve
(1) Purge valve

1. Open purge valve (1) three turns. Purge valve (1) is metric.

2. Start the engine and run at LOW IDLE. A small amount of oil may leak by the purge valve
during the procedure.

3. In order to purge the signal network, start with the TILT control valve. The valve is located at
the cover end.

4. Move the control lever in each direction for 5 seconds. The implement may move or the
implement may not move.

5. Repeat Step 4 for the LIFT valve and for the RIPPER valve.

6. Close off purge valve (1).

Note: The procedure purges the signal network, only if the procedure is done in the above
order. Any other order does not purge all of the air from the signal network.

Resolver Network Check (Implement)

A resolver is a check valve. The resolver compares two pressures. The lower pressure of the two
pressures is blocked. The higher pressure or the higher signal goes to the next component in the
resolver network.

Each implement control valve has a resolver. The resolver compares the highest primary signal in the
control valve to the highest primary signal in the next control valve. The signal resolver network is
arranged in a series. The series stops at the pump compensator valve.

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The signal network can be easily checked. Start the engine and warm up the oil. Run the engine at
HIGH IDLE for the check. Operate each control lever in the following order:

1. Tilt

2. Lift

3. Ripper

If one or more valve sections fail to work correctly, the resolver in the valve section closest to the
pump may be bad.

When any resolver is suspected of being bad, do the following check. Stall any control valve that is
closer to the pump supply. The resolver should supply pump stall pressure to the entire system. Try to
use the malfunctioning valve. If the malfunctioning valve works properly, the resolver is bad. If the
valve does not work properly, the problem is not a resolver problem. If a resolver is bad, remove the
resolver. Check the seals and the resolver. Clean the resolver or replace the resolver.

Illustration 7 g00491596
Resolver

The resolver in each implement control valve section is located directly behind the actuator lever
housing on the top of the valve body.

Main Relief Valve Adjustment (Implement)

Table 15
Tools Required:
1u-5216 Test Block Manifold

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Illustration 8 g00491597
Implement Main Relief Valve
(1) Retainer
(2) Nut
(3) Relief valve

The implement main relief valve has a setting that is higher than the pump cutoff pressure. Use the 1u
-5216 Manifold to test the relief valve on the test bench. The pressure setting for the relief valve is
27600 ± 350 kPa (4003 ± 51 psi). The main relief valve is located on the front of the inlet manifold
near the top.

1. Turn retainer (1) counterclockwise in order to increase the pressure setting and turn the retainer
clockwise in order to decrease the pressure setting.

Note: All adjustments should be made by starting at the lower pressure setting and working
upward.

2. After setting the pressure, tighten retaining nut (2) to a torque of 18 ± 2 N·m (13 ± 1.5 lb ft).

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Illustration 9 g00491598
Location of the Implement Main Relief Valve

Diagnostic Instrument Tests - Steering Hydraulic System

The test is used mainly to determine the location of a problem in the steering hydraulic system.

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine can cause injury to persons on or

near the machine.

Prevent possible injury by performing the procedure that follows before

working on the machine.

Move the machine to a smooth horizontal location. Move away from

working machines and personnel and lower the buckets or implements
(loader and backhoe) and stabilizers to the ground.

Permit only one operator on the machine. Keep all other personnel away
from machine or in view of the operator.

Engage the parking brake. Stop the engine.

Move the hydraulic control levers to all positions to release the pressure
in the hydraulic system.

Table 16
Tools Required:

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2 - 8t-0861 Pressure Gauges( 0 to 60000 kPa (0 to 8700 psi)) or equivalent

2 - 8t-0855 Pressure Gauges( 0 to 4000 kPa (0 to 580 psi)) or equivalent
4 - 1u-5755 Hose Assemblies or equivalent
6v-3121 Multitach
Appropriate instrumentation for measuring oil temperature.

1. Move the machine to a flat open area. Lower all implements to the ground and stop the engine.

Illustration 10 g00491599
(1) Steering Motor
(C) Pressure tap for the left steer pressure
(D) Pressure tap for the right steer pressure

2. Remove the floorplate and install a 1u-5755 Hose Assembly on pressure taps (C), (D), (Y1),
and (Y2).

3. Connect the other ends of the hoses from taps (C) and (D) to two 0 to 60000 kPa (0 to 8700 psi)
gauges.

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Illustration 11 g00805309

4. Connect the other ends of the hoses from taps (Y1) and (Y2) to two 0 to 4000 kPa (0 to 580 psi)
gauges.

Note: If only two hose assemblies and gauges are available, install the hoses alternately on
pressure taps (C) and (Y1) and then on pressure taps (D) and (Y2).

5. Install the floorplate.

6. Install 6v-3121 Multitach on the engine tachometer drive.

7. Start the engine and run at 2100 rpm.

8. Fully engage the parking brake and place all controls in the HOLD position. With the engine at
2100 rpm, record the pressures on the gauges at pressure taps (C), (D), (Y1), and (Y2). The
readings on pressure gauges (Y1) and (Y2) should be below 200 kPa (30 psi) in NEUTRAL. If
either of the pressures is higher than 200 kPa (30 psi), the steering pump could be trying to steer
in one direction. The cause(s) could be the following cause:

a. The tiller handle or the pilot valve linkage is improperly adjusted.

b. The pilot valve is improperly adjusted.

c. The steering pump controls are defective.

d. The pilot control valve is defective.

9. The reading on pressure gauges at pressure taps (C) and (D) should be 2500 ± 300 kPa
(365 ± 45 psi). If the pressures on the gauges at pressure taps (C) and (D) are too high, then the
charge pressure relief valve is improperly adjusted or defective or the oil temperature is too
low. If the pressures are too low, then there is a problem in the charge circuit. The causes could
be the following causes:

a. The charge pressure relief valve is improperly adjusted or failed.

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b. There is a leak in the charge circuit.

c. The motor or the motor flushing valve has wear.

d. The cold oil bypass valve that is in the pressure control valve is worn or improperly
adjusted.

e. The oil level is low.

f. The charge pump is worn.

g. The steering pump is worn.

10. Make sure that the transmission is in NEUTRAL. Release the parking brake and fully activate
the service brake (foot brake). Record the engine speed.

11. With the engine at 2100 rpm, slowly move the steering control lever to the MAXIMUM
STEER RIGHT position. The steering system is in a steer stall condition. Do not hold the
machine in a steer stall condition for more than 20 seconds at a time.

Note: The machine must not move. If the machine moves, the brake system must be checked.

12. With the machine in a right steer stall condition, record pressures (D) and (Y2). Also record the
engine speed and the hydraulic oil temperature. Compare the measured pressure with the
pressure in the chart below. Use the pressure that is closest to the oil temperature that was
measured. Warm up the oil or allow the oil to cool until the oil more closely matches the values
in the chart. Repeat the test.

13. Repeat Steps 11 and 12 for a MAXIMUM STEER LEFT condition and record pressures (C)
and (Y1).

14. If the measured pressures (C) and (D) are as shown in the chart, the pump is developing the
specified pressure.

Table 17
Steering Pump Cutoff Pressure Chart
Engine Speed Oil Temperature
65° ± 5°C (150° ± 10°F) 80° ± 5°C (175° ± 10°F)
2100 rpm 39200 ± 700 kPa (5686 ± 102 psi) 39200 ± 700 kPa (5686 ± 102 psi)

Note: The above test conditions must be matched as closely as possible. Temperatures or
speeds that are lower than the values shown may result in higher pressures.

15. If the pressure (C) and pressure (D) are not as specified in the chart, then determine if pressure
(Y1) and pressure (Y2) are within specification. If (Y1) and (Y2) are not within specification,
see the topic Steering Pilot Valve Tests and Adjustments.

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If the measured pressures for (C) and (D) are higher than the values shown in the chart, then the
pump cutoff pressure must be lowered.

If the measured pressures for (C) and/or (D) are lower than the values shown in the chart, the
cause could be one of the following:

a. The pump cutoff controls are misadjusted or failed.

b. Motor flushing valve is stuck or the valve is not functioning properly.

c. The motor is worn or leaking.

d. Low charge pressure.

e. The pump is worn or leaking.

f. The Pump crossover relief/makeup valves are leaking or set too low.

16. If the engine speed drops (lugs) more than 30 rpm from the recorded 2100 rpm speed in one
steering direction, or both steering directions, during Steps 11 through 13, the corresponding
crossover relief/makeup valve(s) may be leaking or set too low.

Checking and Adjusting Charge Pump Pressure

1. Move the machine to a flat open area. Lower all implements to the ground and stop the engine.

Illustration 12 g00491886
(E) Charge pump relief pressure tap
(F) Charge pump discharge pressure tap

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Illustration 13 g00491890
Bypass and Pressure Control Group
(E) Charge pump relief pressure tap
(F) Charge pump discharge pressure tap

2. Remove the floorplate and install a 1u-5755 Hose Assembly on pressure taps (E) and (F).

3. Connect the other ends of the hoses to the 0 to 4000 kPa (0 to 580 psi) pressure gauges.

4. Install the floorplate.

5. Start the engine and run at 2100 rpm. With all controls in the NEUTRAL position, record the
pressures for taps (E) and (F).

6. The pressure on the gauge for tap (F) should be 345 to 550 kPa (50 to 80 psi) higher than the
pressure on the gauge for tap (E). The pressure at tap (E) should be 2500 ± 300 kPa
(365 ± 45 psi).

7. If the charge pressure is higher than the pressures specified, then the charge pressure relief
valve could be defective or out of adjustment.

8. If the pressure on the gauge for tap (E) is lower than 2500 ± 300 kPa (365 ± 45 psi) during a
neutral steer condition, then one of the following could be the cause:

a. There is a defective charge relief valve in the steering pump.

b. There is a defective cold oil bypass valve in the pressure control valve.

c. The motor flushing valve is worn or stuck open.

d. There is a worn motor.

e. There is a worn steering pump.

f. The charge pump has failed.

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9. If the pressure on the gauge at tap (F) is lower than 1900 kPa (275 psi), in addition to the causes
in Step 8, there could be a defective or improperly adjusted charge loop makeup valve.

10. If the charge pressure is correct, there could be a problem with the charge circuit. The following
test must be run. With the engine at 2100 rpm, release the parking brake and apply the service
brake (foot brake). Move the steering lever slowly to the MAXIMUM STEER RIGHT position.
Do not hold the machine in a steer stall condition for more than 20 seconds at a time.

Note: The machine must not move. If the machine moves, the brake system must be checked.

11. Record the pressure on the gauge for tap (E). If the pressure on the gauge for tap (E) is lower
than 2500 ± 300 kPa (365 ± 45 psi), then one of the following problems could be the cause:

a. The motor flushing valve is stuck open or There is leakage through the valve.

b. The motor is worn.

c. The steering pump is worn.

d. The makeup valve is not functioning properly or the valve is set too low.

e. There is a defective cold oil bypass valve in the pressure control valve.

12. Repeat Steps 8 and 9 for MAXIMUM STEER LEFT position.

Charge Pressure Relief Valve Adjustment

Illustration 14 g00491987
Steering Pump Port Plate (Viewed from Front of Machine)
(1) Locknut
(2) Adjustment screw

1. Stop the engine.

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2. Loosen locknut (1) ( 17 mm (0.67 inch)). Turn adjustment screw (2) (5 mm allen head screw)
clockwise in order to increase the pressure setting or turn the screw counterclockwise in order
to decrease the pressure setting.

Note: All adjustments should be made by starting at the lower pressure setting and working
upward.

3. Tighten locknut (1) and recheck the pressure setting.

Steering Pump Control Neutral Adjustment (Mechanical Zero)

Note: The adjustment is only required for a rebuilt pump.

NOTICE

To avoid system damage, make sure that the hydraulic pump is

properly filled with hydraulic oil before start-up.

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine can cause injury to persons on or

near the machine.

Prevent possible injury by performing the procedure that follows before

working on the machine.

Move the machine to a smooth horizontal location. Move away from

working machines and personnel and lower the buckets or implements
(loader and backhoe) and stabilizers to the ground.

Permit only one operator on the machine. Keep all other personnel away
from machine or in view of the operator.

Engage the parking brake. Stop the engine.

Move the hydraulic control levers to all positions to release the pressure
in the hydraulic system.

Table 18
Tools Required:

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2 - 8t-0861 Pressure Gauges( 0 to 60000 kPa (0 to 8700 psi)) or equivalent

2 - 8t-0855 Pressure Gauges( 0 to 4000 kPa (0 to 580 psi)) or equivalent
3 - 1u-5755 Hose Assemblies or equivalent
6v-3121 Multitach

1. Move the machine to a flat open area. Lower all implements to the ground and stop the engine.

2. Remove the floorplate and install a 1u-5755 Hose Assembly on pressure taps (C) and (D).

Illustration 15 g00491599
(1) Steering motor
(C) Pressure tap for left steer pressure
(D) Pressure tap for right steer pressure

3. Connect the other ends of the hoses from taps (C) and (D) to two 0 to 60000 kPa (0 to 8700 psi)
gauges.

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Illustration 16 g00492023
Steering Pump
(1) Adjustment screw
(X1) Pressure tap
(X2) Pressure tap

4. Connect one end of a 1u-5755 Hose Assembly to tap (X1). Attach the other end to tap (X2),
ensuring equal oil pressure on each side of the control piston.

5. Start and run the engine at 1500 rpm.

6. Look at the pressure gauges. Both readings should be the same pressure. The readings should
be equal to the charge pressure.

Illustration 17 g00492025
Steering Pump Control
(1) Adjustment screw
(2) Locknut

7. If the pressures are not equal, adjust the neutral position of the pump control. Loosen locknut
(2). Use a hex wrench to turn piston rod adjustment screw (1). Turn the screw clockwise or turn
the screw counterclockwise in order to achieve the required spool movement. The pressures on
the gauges should change. Adjust screw (1) until the pressures are equal.

Note: All adjustments should be made by starting at the lower spring tension and working
upward.

8. Stop the engine. Remove the two 60000 kPa (8700 psi) gauges and replace the gauges with two
4000 kPa (580 psi) gauges.

9. Repeat Steps 5 through 8.

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10. Tighten locknut (2). Remove the pressure gauges, hoses, and connectors from pressure taps (C)
and (D). Remove the hose from pressure taps (X1) and (X2).

Steering Pump Control Valve Neutral Adjustment (Hydraulic Zero)

Do the Charge Pump Relief Valve Pressure Test before doing the test. Also, do the Steering Pump
Control Neutral Adjustment (Mechanical Zero) before doing the test. These tests ensure that the
mechanical neutral position of the swashplate is correct.

Personal injury or death can result from sudden machine movement.

Sudden movement of the machine can cause injury to persons on or

near the machine.

Prevent possible injury by performing the procedure that follows before

working on the machine.

Move the machine to a smooth horizontal location. Move away from

working machines and personnel and lower the buckets or implements
(loader and backhoe) and stabilizers to the ground.

Permit only one operator on the machine. Keep all other personnel away
from machine or in view of the operator.

Engage the parking brake. Stop the engine.

Move the hydraulic control levers to all positions to release the pressure
in the hydraulic system.

Table 19
Tools Required:
2 - 8t-0861 Pressure Gauges( 0 to 60000 kPa (0 to 8700 psi)) or equivalent
2 - 8t-0855 Pressure Gauges( 0 to 4000 kPa (0 to 580 psi)) or equivalent
4 - 1u-5755 Hose Assemblies or equivalent
6v-3121 Multitach

1. Move the machine to a flat open area. Lower all implements to the ground and stop the engine.

2. Remove the floorplate and install a 1u-5755 Hose Assembly on pressure taps (C) and (D).

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Illustration 18 g00491599
(1) Steering motor
(C) Pressure tap for left steer pressure
(D) Pressure tap for right steer pressure

3. Connect the other ends of the hoses from taps (C) and (D) to two 0 to 60000 kPa (0 to 8700 psi)
gauges.

4. Install a 1u-5755 Hose Assembly on pressure taps (X1) and (X2). Connect the other ends of the
hoses from taps (X1) and (X2) to two 0 to 4000 kPa (0 to 580 psi) gauges.

5. Start and run the engine at 1500 rpm.

Illustration 19 g00492033
Steering Pump
(2) Adjustment screw
(X1) Pressure tap
(X2) Pressure tap

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6. Look at the pressure gauges that are connected to pressure taps (C) and (D). The readings
should be equal. The pressures should be equal to the charge pressure.

7. Look at the pressure gauges that are connected to pressure taps (X1) and (X2). Both readings
should be within 345 kPa (50 psi) of each other.

8. If the readings are not within 345 kPa (50 psi), the control valve must be adjusted.

Illustration 20 g00805287

Note: Adjustment screw (2) is an eccentric adjuster. One half revolution of the screw is all of
the adjustment possible. A small amount of movement of screw (2) makes a large pressure
difference.

9. Loosen locknut (3). Turn screw (2) until the pressure gauges have equal readings. Tighten the
locknut.

Note: All adjustments should be made by starting at the lower spring tension and working
upward.

10. When the readings are correct, remove the gauges.

11. If the control valve cannot be adjusted, the control valve must be repaired or replaced.

Checking and Adjusting Steering Pump Cutoff Pressure

Note: Steering charge pump pressure and steering pilot pressure tests should be run before running
the test.

Personal injury or death can result from sudden machine movement.

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Sudden movement of the machine can cause injury to persons on or

near the machine.

Prevent possible injury by performing the procedure that follows before

working on the machine.

Move the machine to a smooth horizontal location. Move away from

working machines and personnel and lower the buckets or implements
(loader and backhoe) and stabilizers to the ground.

Permit only one operator on the machine. Keep all other personnel away
from machine or in view of the operator.

Engage the parking brake. Stop the engine.

Move the hydraulic control levers to all positions to release the pressure
in the hydraulic system.

Table 20
Tools Required:
2 - 8t-0861 Pressure Gauges ( 0 to 60000 kPa (0 to 8700 psi)) or equivalent
2 - 1u-5755 Hose Assemblies or equivalent
6v-3121 Multitach
Appropriate instrumentation for measuring oil temperature

1. Move the machine to a flat open area. Lower all implements to the ground and stop the engine.

2. Remove the floorplate and install a 1u-5755 Hose Assembly on pressure taps (C) and (D).

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Illustration 21 g00491599
(1) Steering motor
(C) Pressure tap for left steer pressure
(D) Pressure tap for right steer pressure

3. Connect the other ends of the hoses from taps (C) and (D) to two 0 to 60000 kPa (0 to 8700 psi)
gauges.

4. Install the floorplate.

5. Install the 6v-3121 Multitach on the engine tachometer drive.

6. Start the engine and record the rpm. The reading should be 2100 rpm.

7. Make sure that the transmission is in NEUTRAL. Release the parking brake and fully activate
the service brakes (foot brake).

8. With the engine still at 2100 rpm, slowly move the steering control lever to the MAXIMUM
STEER RIGHT position. The maximum position puts the steering system in a steer stall
(cutoff) condition. Do not hold the machine in a steer stall condition for more than 20 seconds
at a time.

Note: The machine must not move. If the machine moves, the brake system must be checked.

9. With the machine in a right steer stall condition, record pressure (D), engine speed, and
hydraulic oil temperature. Compare the measured pressure with the pressure specified in the
chart below which is closest to the oil temperature measured. Warm up the oil or allow the oil
to cool until the temperature matches the values in the chart and repeat the test.

10. Repeat Steps 8 and 9 for a MAXIMUM STEER LEFT condition and record pressure (C).

11. If the measured pressures for (C) and (D) during Steps 9 and 10 are as shown in the chart, then
the pump cutoff valve is correctly set.

Table 21
Steering Pump Cutoff Pressure Chart
Engine Speed Oil Temperature
65° ± 5°C (150° ± 10°F) 80° ± 5°C (175° ± 10°F)
2100 rpm 39200 ± 700 kPa (5686 ± 102 psi) 39200 ± 700 kPa (5686 ± 102 psi)

Note: The above test conditions must be matched as closely as possible. Temperatures and
speeds that are lower than shown may result in pressures higher than the values shown in the
chart.

12. If one pressure (C) or (D) is low and the other pressure is correct, the problem is probably with
the cross port relief/makeup valve for the side with the low pressure. If the measured pressures

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for taps (C) and (D) are higher than the values shown in the chart, then the pump cutoff
pressure must be lowered.

If the measured pressures for (C) and (D) are lower than the values shown in the chart, then the
cause could be one of the following causes:

a. The pump cutoff controls are misadjusted or failed.

b. Low pilot pressure.

c. The motor flushing valve is stuck or not functioning properly.

d. The motor has failed or the motor is leaking.

e. Low charge pressure.

f. The pump has failed or the pump is leaking.

g. The pump crossover relief/makeup valves are set too low or not functioning properly.

Steering Pump Cutoff Pressure Adjustment

Illustration 22 g00492151
Steering Pump Port Plate (Viewed from Front of Machine)
(1) Locknut
(2) Adjustment screw

1. Stop the engine.

2. Loosen locknut (1). Turn adjustment screw (2) clockwise in order to increase the pressure
setting or turn the screw counterclockwise in order to decrease the pressure setting.

Note: All adjustments should be made by starting at the lower pressure setting and working
upward.

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3. Tighten locknut (1) and recheck the pressure setting.

Checking and Adjusting Steering Pump Crossover Relief Makeup Valves

Note: It is not recommended that the crossover relief/makeup valves be adjusted on the machine. The
test suggests a procedure to isolate a malfunctioning crossover relief/makeup valve. Also, the test
provides instructions to bench test the valve and instructions to adjust the valve.

Table 22
Tools Required:
2 - 8t-0861 Pressure Gauges ( 0 to 60000 kPa (0 to 8700 psi)) or equivalent
2 - 1u-5755 Hose Assemblies or equivalent
9u-5829 Manifold Block
6v-3121 Multitach

Vehicle Test

1. Move the machine to a flat, open area. Lower all implements to the ground and stop the engine.

2. Install 6v-3121 Multitach on the engine tachometer drive.

3. Start the engine and run at 2100 rpm.

4. Make sure that the transmission is in NEUTRAL. Release the parking brake and fully activate
the service brakes (foot brake). Record the engine speed.

5. With the engine at 2100 rpm, slowly move the steering control lever to the MAXIMUM
STEER RIGHT position. The maximum position puts the steering system in a steer stall
(cutoff) condition. Record engine speed. Do not hold the machine in steer stall condition for
more than 20 seconds at a time.

6. Repeat Step 5 for a MAXIMUM STEER LEFT condition.

7. If the engine speed drops (lugs) more than 30 rpm from the recorded 2100 rpm speed in one
steering direction, or both steering directions during Steps 5 and 6, then the corresponding
crossover relief/makeup valve(s) may be leaking or set too low.

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Illustration 23 g00492154
Steering Pump Port Plate (Viewed from Front of Machine)

Bench Test

The crossover/makeup valve has a setting higher than the steering pump cutoff, and therefore, the
valve cannot be adjusted on the machine. Use the 9u-5829 Manifold Block to test the crossover
relief/makeup valve on the test bench. The setting for the valve is 46000 ± 1000 kPa (6672 ± 145 psi)
under the following conditions: SAE (10) hydraulic oil, 65°C (150°F) and flow rate between
20 to 100 L/min (5 to 26 gpm).

Steering Pump Case Pressure Test

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Personal injury or death can result from sudden machine movement.

Sudden movement of the machine can cause injury to persons on or

near the machine.

Prevent possible injury by performing the procedure that follows before

working on the machine.

Move the machine to a smooth horizontal location. Move away from

working machines and personnel and lower the buckets or implements
(loader and backhoe) and stabilizers to the ground.

Permit only one operator on the machine. Keep all other personnel away
from machine or in view of the operator.

Engage the parking brake. Stop the engine.

Move the hydraulic control levers to all positions to release the pressure
in the hydraulic system.

Illustration 24 g00492159
Pressure Control Valve
(G) Steering pump case drain pressure tap

1. Move the machine to a flat open area. Lower all implements to the ground and stop the engine.

2. Remove the floorplate and install a 1u-5755 Hose Assembly on pressure tap (G).

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3. Connect the other ends of the hose from tap (G) to a 0 to 1400 kPa (0 to 200 psi) gauge.

4. Install the floorplate.

5. Start and run the engine at HIGH IDLE.

6. The gauge reading must be less than 175 kPa (25 psi).

7. If the gauge reading is more than 175 kPa (25 psi), check the hose from the pressure control
valve to the tank for an obstruction.

8. Stop the engine and remove the test equipment.

Steering Pilot Valve Tests and Adjustments

Illustration 25 g00492423
Pilot Valve
(1) Lever
(2) Hole
(3) Jam nut
(4) Bolt
(5) Plunger
(6) Jam nut
(7) Sleeve

Note: If the pilot valve has unequal pressure right to left or unequal steering turn diameter, complete
the following tests:

Steering Pilot Valve Alignment

1. Shut off the engine and engage the parking brake.

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Illustration 26 g00492426
Tiller Assembly and Pilot Valve
(1) Lever
(2) Hole
(8) Mounting plate assembly
(9) Hole
(10) Housing
(11) Bolt
(12) Roller

2. Insert a 3.2 mm (0.125 inch) diameter pin through hole (2) and through hole (9). If the pin does
not go through both holes, an alignment adjustment is required.

3. If the pin goes through both holes (2) and (9), remove the pin. Release the parking brake, and
insert the pin through holes (2) and (9) again. Do not move the tiller in order to align the holes.
If the pin goes through both holes, the alignment of the valve is correct and no further
adjustment is needed. If the pin does not go through both holes, an alignment adjustment is
required.

4. If an adjustment is required, engage the parking brake and disconnect all hydraulic lines to the
pilot valve.

5. Loosen two bolts (11) that hold the pilot valve to mounting plate assembly (8).

6. Install a 3.2 mm (0.125 in) diameter pin into hole (2) in lever (1) and hole (9) in housing (10).

7. Line up the pilot valve so that roller (12) is at the bottom of lever (1) and there is no preload on
either plunger (5). Tighten mounting bolts (11) and remove the pin.

8. Check the adjustment by releasing the parking brake and reinserting the pin through holes (2)
and (9). Do not move the tiller in order to align the holes. If the pin goes through both holes, the
alignment of the valve is correct and no further adjustment is needed. If the pin does not go
through both holes, the alignment is not correct and the adjustment should be repeated.

Note: The pilot valve may move if the transmission control cables are too tight or misadjusted.

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9. Verify that the tiller moves smoothly in both directions.

10. Connect the hydraulic lines. Start the engine, and remove the air in the pilot circuit.

Actuator Adjustment

1. Shut off the engine. Engage the parking brake. Remove or pull up the boot in order to allow
access to jam nut (3).

2. Loosen two jam nuts (3) and adjust two bolts (4) inward until there is a gap between the head of
bolts (4) and plungers (5) on both sides of the valve.

3. Adjust bolts (4) outward in order to remove all free play between the head of bolts (4) and
plungers (5). Do not preload plunger (5).

4. Tighten jam nuts (3) to a torque of 12 ± 4 N·m (9 ± 3 lb ft) and reinstall the boot.

Pressure Adjustment

Note: Check the charge pressure before adjusting the pilot pressure.

Illustration 27 g00805309

1. Shut off the engine. Engage the parking brake. Remove or pull up the boot in order to allow
access to plunger jam nuts (6).

2. Install a 6v-3081 Hose with a 0 to 4000 kPa (0 to 580 psi) pressure gauge attached to pressure
taps (Y1) and (Y2).

3. Make a copy of the angle measurement guide and cut out the guide. With the parking brake ON
(ENGAGED), tape the portion of the guide with the letters to the housing of the tiller as shown
in the photo below. The arrow point that corresponds with the letter “N” should be in line with

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the center of the stud as shown. Make a mark on the end of the stud so that it lines up with the
arrow point that corresponds with the letter “N”.

Illustration 28 g00492486
Angle Measurement Guide

Illustration 29 g00801696

4. Start and run the engine at LOW IDLE. Read the pressure on the 2 gauges. The pressure should
read between 0 and 200 kPa (0 to 30 psi). If the pressure is greater than 200 kPa (30 psi) on
either gauge, loosen jam nut (6) for the side with the high-pressure reading. Loosen sleeve (7)
until the pressure on the gauge is less than 200 kPa (30 psi).

5. If the pressure on either gauge reads 0 kPa (0 psi), loosen jam nut (6) for the side with no
pressure reading. Tighten sleeve (7) until the pressure is between 0 kPa and 200 kPa
(0 psi and 30 psi).

6. Tighten jam nuts (6) to a torque of 30 ± 15 N·m (22 ± 11 lb ft).

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7. Place the transmission in NEUTRAL. Firmly depress the service brake pedal and release the
parking brake. The pressure readings on the gauges should not change. If the pressures change,
the pilot valve must be aligned.

8. With the service brake pedal still depressed, use the angle measurement guide and shift the tiller
so that positions (A), (B), and (C) in both STEER LEFT and STEER RIGHT line up with the
mark on the end of the stud. Note the pressure on each gauge in each position and compare the
pressures to the pressures in the following table.

Table 23
Pilot Pressure Chart
Tiller Position Y1 Y2
(A) Steer Left 745 ± 100 kPa (108 ± 15 psi) 0 to 200 kPa (0 to 29 psi)
(B) Steer Left 1200 ± 170 kPa (174 ± 25 psi) 0 to 200 kPa (0 to 29 psi)
(C) Steer Left 2060 ± 240 kPa (300 ± 35 psi) 0 to 200 kPa (0 to 29 psi)
(A) Steer Right 0 to 200 kPa (0 to 29 psi) 745 ± 100 kPa (108 ± 15 psi)
(B) Steer Right 0 to 200 kPa (0 to 29 psi) 1200 ± 170 kPa (174 ± 25 psi)
(C) Steer Right 0 to 200 kPa (0 to 29 psi) 2060 ± 240 kPa (300 ± 35 psi)

9. If the pressures are low in both directions, increase the engine speed. If the pressures increase,
the problem is in the charge loop.

10. If the pressure is low in one direction only, the pilot valve may be dirty or defective. Check the
pilot valve for debris or damage.

Steering Motor Rotary Group Adjustment

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Illustration 30 g00492490
Motor Rotary Group
(1) Port plate
(2) Cylinder barrel
(3) Spacer
(4) Center pin
(5) Compression springs (four)
(6) Piston (seven)
(7) Shaft
(8) Bearings
(9) Shims
(10) Cover assembly
(11) Ring

The steering motor rotary group is divided into a mechanical drive group (shaft (7), bearings (8), and
cover (10)) and a hydraulic group ( barrel (2), port plate (1), spacer (3), compression springs (5),
pistons (6), and center pin (4)).

If parts of the motor are serviced, there are two critical dimensions which should be checked during
assembly of the motor rotary group. Shims (9) on the mechanical drive group and one of the four
spacers (3) on the hydraulic group are used to get the respective dimensions.

NOTICE

To avoid system damage, make sure that the hydraulic motor is

properly filled with hydraulic oil before start-up.

Use the following chart for the adjustment dimensions for servicing the rotary group.

Table 24
Type of Pt. Gauge Block Dial Gauge Block Dial Indicator
Motor No. Dimension A Indicator Dimension B Reading
Reading
Steering 9t8345 107.3 mm -0.1 mm 136.5 mm -0.1 to -0.2 mm
(4.224 inch) (-.004 inch) (5.374 inch) (-.004 to -.008 inch)

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Illustration 31 g00492543
Adjusting Dimensions
(12) Centering pin (tooling)
(A) Distance from ring (11) to shaft (7)
(B) Distance from shaft (7) to centering pin (12)
(C) Play (spacer (3) to center pin (4))

40 Degree Motor Displacement Angle Adjustment

Table 25
Tools Required:
Gauge Blocks (Use standard gauge set)
8s-2328 Dial Indicator Group
8t-7760 Measuring Kit, Tool Group
8t-7756 Support

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Illustration 32 g00492547
Dial Indicator Setup
(13) Gauge blocks
(14) Support

The shim adjustment is necessary in order to maintain an exact angle between the center lines of drive
shaft (7) and center pin (4). The adjustment maintains the proper alignment between barrel (2) and
pistons (6).

Illustration 33 g00492548
Measurement for Shim Thickness
(14) Support
(15) Cover
(16) Ring location
(17) Shims
(18) Boss

Place support (14) on a surface plate. Position gauge blocks (13) on the support in order to get
dimension (A). Set the indicator in position over the gauge blocks and zero the dial.

Position the mechanical drive group on support (14) so that boss (18) is located over the hole in the
support. Place cover (15) (without the seal and O-ring) on the drive group. Do not install the ring at
location (16). Slide the drive group and the support under the dial indicator. Add shims (17) to get a
reading on the indicator between 0 and -0.10 mm (0 and -.004 in).

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Illustration 34 g00805312

Lift-Off Limitation Adjustment (Cylinder Barrel to Port Plate Maximum

Separation)

Table 26
Tools Required:
Motor 9t8345
Gauge Blocks -
Dial Indicator Group 8s2328
Measuring Kit, Tool Group (8t7760) Support 8t7756
Cylinder 8t7764
Centering Pin 8t7763
Centering Disc (with two screws) 8t7759

The clearance from spacer (3) to pin (4), in combination with the compression springs (5), maintains
the barrel (2) to port plate (1) separation. The maximum separation limits the leakage during startup
and downhill operation.

The adjustment procedure determines the correct size of the spacer required for the distance between
the center pin and centering pin (12). With correct distance (B), clearance (C) between spacer (3) and
center pin (4) is 0.10 to 0.25 mm (.004 to .010 in)

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Illustration 35 g00492634
Dial Indicator Setup
(13) Gauge blocks
(19) Support

Place support (19) on a surface plate. Using gauge blocks (13), build up dimension (B) as listed in the
chart. Set up the dial indicator and zero.

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Illustration 36 g00492639
Spacer Installation
(1) Port plate
(2) Cylinder barrel
(3) Spacer
(20) Wire
(21) Cylinder

Use wire (20), to guide spacer (3) into cylinder (21). Place center pin in cylinder (21) without
compression springs (5).

NOTICE

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In order to avoid damage to center pin (4) and support (19) in the next
step, place measuring kit cylinder (24) over support and lay cylinder on
its side (horizontal).

Illustration 37 g00492668
Measurement for Spacer Thickness
(1) Port plate
(2) Cylinder barrel
(3) Spacer
(4) Center pin
(12) Centering pin
(19) Support
(22) Centering disc
(23) Lifting screws
(24) Measuring kit cylinder
(25) Centering hole

Insert barrel (2), spacer (3), and center pin (4) into the centering hole (25) in support (19). Stand the
cylinder in a vertical position. Insert centering pin (12) in port plate (1) and barrel (2). Position
centering disc (22) and lifting screws (23) over the port plate. Slide the assembly under the dial
indicator.

The dial indicator must read between -0.10 and -0.20 mm (-.004 and -.008 in). The motor has four
different sizes of spacers. There is a minimum spacer size. Each succeeding size of the spacers is
0.10 mm (.004 in) thicker. Depending on the reading on the dial indicator, select the correct spacer.

Table 27
Motor Spacer Thickness Difference From Minimum Spacer
9t8345 9t1650 9.6 mm (0.38 inch) 0 mm (0 inch) Minimum Spacer
9t1651 9.7 mm (0.382 inch) .1 mm (0.004 inch)

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9t1646 9.8 mm (0.386 inch) .2 mm (0.008 inch)

9t1648 9.9 mm (0.39 inch) .3 mm (0.012 inch)

For example, tolerance for dimension (B) is −0.40 mm (−0.016 inch) on the dial indicator. Remove
the spacer with the minimum thickness and replace the spacer with a spacer that increases the
indicator reading by 0.20 mm (0.008 inch) in order to give a dimension (B) of 136.3 mm (5.37 inch).

Once the correct spacer has been selected, center pin (4) can be removed. Compression springs (5)
can be inserted by using wire (20) as a guide.

Illustration 38 g00492802
Compression Springs Installation
(5) Compression springs
(20) Wire

Copyright 1993 - 2022 Caterpillar Inc. Fri Dec 9 13:53:19 UTC+0300 2022 
All Rights Reserved.
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