D6T Track-Type Tractor Systems Piston Pump (Steering) - Test and Adjust Caterpillar

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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.

Specifications

Illustration 1	g02480718

Introduction

This procedure includes the following tests and the following adjustment procedures:

• "Test Procedure - Mechanical Neutral Adjustment"

• "Test Procedure - Neutral Position for the Steering Pump Control Valve"

• "Test Procedure - Pressure Override (POR)"

• "Test Procedure - Crossover Relief and Makeup Valves"

• "Adjustment Procedure - Mechanical Neutral Adjustment"

• "Adjustment Procedure - Neutral Position for the Steering Pump Control Valve"

• "Adjusting Procedure - Pressure Override (POR)"

• "Adjustment Procedure - Crossover Relief and Makeup Valve"

Required Tools

Illustration 2	g02571852
Tooling (A)

Illustration 3	g01623860
Tooling (C)

Illustration 4	g01869097
Tooling (D)

Illustration 5	g01784963
Tooling (F)

Test Preparation - Mechanical Neutral Adjustment

1. Move the machine to a smooth horizontal location.

2. Lower all of the implements.

3. Shut off the engine.

4. Turn the key to the ON position. Make sure that the implement lockout switch is turned to the UNLOCKED position. Move the implement control levers to all positions several times in order to release any pressure in the hydraulic system.

   Note: Actuate the steering control tiller to relieve any trapped pressure in the steering circuit.

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   Illustration 6	g01361568
   The test ports for the right and left steering loop is located under the floor pan in the cab.

5. Locate the test port for the right steering loop (HD) and the test port for the left steering loop (HC).

6. Attach one set of Tooling (A) or (C) to test port (HD).

7. Attach one set of Tooling (A) or (C) to test port (HC).
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   Illustration 7	g02332055
   (X1) Test port (X2) Test port

8. Remove the plugs in test port (X1) and (X2). Install one end of Tooling (D) into test port (X1). Install the other end of Tooling (D) into test port (X2).

Test Procedure - Mechanical Neutral Adjustment

1. Perform the steps in the "Test Preparation - Mechanical Neutral Adjustment" and then continue to the following steps.

2. Start the engine. Warm the hydraulic oil to a minimum temperature of 65 °C (150 °F).

3. Engage the parking brake.

4. Operate the engine at 1850. Place all controls in the HOLD position.

5. Check the pressures at test port (HD) and (HC). The pressures should be within 345 kPa (50 psi) of each other.

6. If the pressures are within the specified limit, the test is complete.

7. If the pressures are not within the specified limit, perform the procedure in "Adjustment Procedure - Mechanical Neutral Adjustment".

Adjustment Procedure - Mechanical Neutral Adjustment

This adjustment is in most cases, required only for a rebuilt steering pump.

1. Perform the procedure in "Test Procedure - Mechanical Neutral Adjustment".
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   Illustration 8	g02332055
   (3) Adjustment Screw (4) Locknut

2. Locate adjustment screw (3) on the steering pump.

3. Loosen locknut (4) while you hold adjustment screw (3) in place.

4. Turn adjustment screw (3) clockwise or turn adjustment screw (3) counterclockwise until the pressures at port (HC) and (HD) are within 345 kPa (50 psi) of each other.

5. If the pressures at port (HC) and (HD) cannot be brought within 345 kPa (50 psi) of each other, perform the procedure in "Test Procedure - Mechanical Neutral Adjustment".

6. When the pressures are within the specified limit, the adjustment procedure is complete.

7. Hold the adjustment screw (3) and tighten the locknut (4).

8. Remove Tooling (D) and tighten (X1) and (X2) to a torque of 15 N·m (11 lb ft).

Test Preparation - Neutral Position for the Steering Pump Control Valve

1. Move the machine to a smooth horizontal location.

2. Lower all of the implements.

3. Shut off the engine.

4. Turn the key to the ON position. Make sure that the implement lockout switch is turned to the UNLOCKED position. Move the implement control levers to all positions several times in order to release any pressure in the hydraulic system.

   Note: Actuate the steering control tiller to relieve any trapped pressure in the steering circuit.

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   Illustration 9	g01361568
   The test ports for the right and left steering loop is located under the floor pan in the cab.

5. Locate the test port for the right steering loop (HD) and the test port for the left steering loop (HC).

6. Attach one set of Tooling (A) or (C) to test port (HD).

7. Attach one set of Tooling (A) or (C) to test port (HC).

8. Check the pressure of the charge pressure oil before adjusting the neutral position of the steering pump control valve. Also, perform the adjustment procedure for the mechanical neutral position for the actuator piston. This adjustment procedure will ensure that the mechanical neutral position of the swashplate is correct.
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   Illustration 10	g02332055

9. Install one set of tooling (F) into test port (X1). Install another set of tooling (F) into test port (X2).

10. Attach two sets of Tooling (A) or (C) to Tooling (F).

Test Procedure - Neutral Position for the Steering Pump Control Valve

1. Perform the steps in the "Test Preparation - Neutral Position for the Steering Pump Control Valve" and then continue to the following steps.

2. Start the engine. Warm the hydraulic oil to a minimum temperature of 65 °C (150 °F).

3. Engage the parking brake.

4. Operate the engine at 1850. Place all controls in the HOLD position.

5. Check the pressure at test port (X1) and (X2). Both readings should be within 48 kPa (7 psi) of each other.

6. If the pressures are not within the specifications, perform the procedure in "Adjustment Procedure - Neutral Position for the Steering Pump Control Valve".

Adjustment Procedure - Neutral Position for the Steering Pump Control Valve

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Illustration 11	g02332277
(5) Eccentric adjustment screw (6) Locking screw

1. Locate eccentric adjustment screw (5) on the steering pump.

   Note: One-half revolution of eccentric adjustment screw (5) is the maximum adjustment. A small amount of movement of the screw makes a large pressure difference.

2. Loosen locking screw (6) while you hold eccentric adjustment screw (5).

3. Turn eccentric adjustment screw (5) until the pressures at test port (1) and (2) are within 48 kPa (7 psi) of each other.

4. When the pressures at test port (X1) and (X2) are within 48 kPa (7 psi) of each other, tighten locking screw (6). Make sure that you hold eccentric adjustment screw (5) while you tighten locking screw (6).

5. When the pressures at test port (X1) and (X2) are within 48 kPa (7 psi) of each other, the adjustment procedure is complete.

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

7. Remove Tooling (F) and tighten (X1) and (X2) to a torque of 15 N·m (11 lb ft).

Test Preparation - Pressure Override (POR)

1. Move the machine to a smooth horizontal location.

2. Lower all of the implements.

3. Shut off the engine.

4. Turn the key to the ON position. Make sure that the implement lockout switch is turned to the UNLOCKED position. Move the implement control levers to all positions several times in order to release any pressure in the hydraulic system.

   Note: Actuate the steering control tiller to relieve any trapped pressure in the steering circuit.

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   Illustration 12	g01361568
   The test ports for the right and left steering loop is located under the floor pan in the cab.

5. Locate the test port for the right steering loop (HD) and the test port for the left steering loop (HC).

6. Attach one set of Tooling (A) or (C) to test port (HD).

7. Attach one set of Tooling (A) or (C) to test port (HC).

Test Procedure - Pressure Override (POR)

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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.

Note: Test the charge pump pressure and test the steering pilot pressure before running this test.

1. Perform the steps in the "Test Preparation - Pressure Override (POR)" and then continue to the following steps.

2. Start the engine and run the engine at 1850.

3. The transmission must be in NEUTRAL. Disengage the parking brake. Fully activate the service brakes.

4. Slowly move the steering control lever to the MAXIMUM STEER RIGHT position. The maximum position puts the steering system in a steer stall condition (cutoff). 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, check the brake system.

5. With the machine in a steer stall condition, record pressure in Table 1. High-pressure cutoff should be 42000 ± 700 kPa (6092 ± 102 psi).

6. Repeat Steps 4 and 5 in a MAXIMUM STEER LEFT condition.

7. During Step 5 and Step 6, if pressures (HC) and (HD) are within specifications, the pump compensator valve is correctly set.

8. If one pressure (HC) or (HD) is low and the other pressure is correct, the problem is probably with the crossover relief/makeup valve for the side with the low pressure. If pressures (HC) and (HD) are higher than the specified values, adjust the POR valve.

   If pressures (HC) and (HD) are lower than the specified values, check these possible causes:

   • The pump compensator valve is misadjusted or failed.

   • The motor flushing valve is stuck or malfunctioning.

   • The motor has failed or the motor is leaking.

   • The charge pressure is low.

   • The pump has failed or the pump is leaking.

   • The crossover relief/makeup valves are set too low or the valves are malfunctioning.

Adjusting Procedure - Pressure Override (POR)

Illustration 13	g02332800
(7) Locknut (8) Adjustment screw (9) Cap

1. Stop the engine.

2. Remove cap (9). Loosen locknut (7). Turn adjustment screw (8) clockwise in order to increase the pressure setting or turn the screw counterclockwise in order to decrease the pressure setting.

   Note: Each turn changes the pressure by 9700 kPa (1400 psi).

   Note: To decrease the setting, turn adjustment screw (8) counterclockwise past the desired pressure setting. Then, turn adjustment screw (8) clockwise to the correct pressure setting. This method of adjusting the pressure setting eliminates any movement in the threads.

3. Hold the adjustment screw (8) and tighten the locknut (7) to a torque of 15 N·m (11 lb ft).

Test Preparation - Crossover Relief and Makeup Valves

1. Move the machine to a smooth horizontal location.

2. Lower all of the implements.

3. Shut off the engine.

4. Turn the key to the ON position. Make sure that the implement lockout switch is turned to the UNLOCKED position. Move the implement control levers to all positions several times in order to release any pressure in the hydraulic system.

   Note: Actuate the steering control tiller to relieve any trapped pressure in the steering circuit.

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   Illustration 14	g01361568
   The test ports for the right and left steering loop is located under the floor pan in the cab.

5. Locate the test port for the right steering loop (HD) and the test port for the left steering loop (HC).

6. Attach one set of Tooling (A) or (C) to test port (HD).

7. Attach one set of Tooling (A) or (C) to test port (HC).

Test Procedure - Crossover Relief and Makeup Valves

Illustration 15	g02480739
(10) Crossover Relief and Makeup Valve

1. Perform the steps in the "Test Preparation - Crossover Relief and Makeup Valves" and then continue to the following steps.

2. Start the engine. Warm the hydraulic oil to a minimum temperature of 65 °C (150 °F).

3. Engage the parking brake.

4. Fully depress the travel control pedal. The transmission must be in NEUTRAL. The steering control lever must be in the NEUTRAL position. Release the parking brake.

5. Operate the engine at 1850 and slowly move the steering control lever to the MAXIMUM STEER RIGHT position. The steering system is in the STEER STALL CONDITION.

   Note: Do not hold the machine in a STEER STALL CONDITION for more than 5 seconds at a time.

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

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

7. If the engine speed drops more than 30 rpm from 1850 in one direction or both directions during Steps 5 and 6, the corresponding crossover relief and makeup valve may be leaking or set too low.

8. Perform the procedure in "Adjustment Procedure - Crossover Relief and Makeup Valve".

Adjustment Procedure - Crossover Relief and Makeup Valve

Illustration 16	g02480739
(10) Crossover Relief and Makeup Valve

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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.

Note: There is no on board test that will indicate that a crossover relief valve is properly set. If the pump has been rebuilt, you may want to check the valves for proper settings. The valve can only be tested and adjusted on the bench.

Bench Test

The crossover relief and makeup valve has a setting that is higher than the main relief valve for the steering. The valve cannot be adjusted on the machine.

Use the 9U-5829 Manifold to test the crossover relief and makeup valve on the test bench. The setting for the valve is 46000 ± 1000 kPa (6670 ± 145 psi) under the following conditions:

• SAE 10W hydraulic oil

• 65°C (150°F)

• Flow rate between 20 to 100 L/min (5 to 26 gpm)

If the crossover relief and makeup valve is not within the specifications, use the adjustment screw to change the pressure setting until the specifications are met.