770G and 772G Off-Highway Truck: Piston Pump (Steering, Fan) - Test and Adjust

Introduction

We are checking the pressures at the control manifold for the steering system.

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

• High Pressure Cutoff Valve
• Flow Compensator Valve

Required Tools

Table 1

Required Tools
Item		Part Number	Description	Qty
B		198-4240	Digital Pressure Indicator Gp	1
B1		198-4234	Digital Indicator	1
B2		198-4239	Pressure Sensor Gp ( 41368 kPa (6000 psi))	2
B3		198-4236	Adapter Cable As Coupler	2

Machine Preparation

ReferenceRefer to the Testing and Adjusting section of Service Manual, KENR9935, "General Information" to view information regarding the machine preparation.

ReferenceRefer to the Testing and Adjusting section of the Service Manual, KENR9935, "Visual Inspection" to view information regarding the machine preparation.

View (A) of control manifold (B) .



1. Locate the test port (C) on control manifold (B). Control manifold (B) located on the right frame behind the right front suspension cylinder.

2. Attach tooling (B) to test port (C) .

3. Locate steering piston pump (D) .

4. Locate pressure and flow compensator valve (E) on steering piston pump (D) .

High Pressure Cutoff Valve

1. Start the engine.

2. Operate the engine at HI IDLE. Turn the steering wheel to the right or turn the steering wheel to the left until the steering cylinder stop is reached. Then, continue turning the steering wheel against the stop. Hold the steering wheel in this position for 3 seconds and then release the steering wheel. Continue this step until the oil in the steering system reaches at least 38 °C (100 °F) to 93 °C (200 °F).

3. Check the cutoff pressure at pressure tap (C) for the steering system. Pressure tap (C) is part of the steering control manifold. The steering control manifold is mounted on the outside of the right frame behind the suspension cylinder.Note: The pressure gauge needs to withstand the maximum pressure from the steering piston pump.

4. Operate the engine at HI IDLE. Turn the wheels to the right or the left until the steering cylinder stop is reached. Check the pressure while you are turning the steering wheel against the stop. The pressure setting of the high-pressure cutoff valve at zero flow is 20850 kPa (3024 psi) to 21550 kPa (3126 psi).

5. If the pressure needs to be adjusted, stop the engine.

6. Remove cap (4) from setscrew (5) on high-pressure cutoff valve (6) .

7. Loosen locknut (3) of high-pressure cutoff valve (6) .

8. With an allen wrench, rotate setscrew (5) clockwise by 1/4 turn in order to raise the pressure. Rotate setscrew (3) counterclockwise by a 1/4 turn in order to lower the pressure. Each 1/4 turn of setscrew (3) changes the pressure approximately 1310 kPa (190 psi). Refer to Illustration 6 in order to view the location of setscrew (3) .

9. Repeat Steps 1 through 8 until the pressure setting is correct.

10. Remove the test equipment.

Flow Compensator Valve

1. Start the engine.

2. Operate the engine at HI IDLE. Turn the steering wheel until the wheels stop turning. Hold the steering wheel in this position for 3 seconds and then release the steering wheel. Continue with Step 2 until the oil in the steering system reaches at least 38 °C (100 °F) to 93 °C (200 °F).The steering system pressure will drop to low-pressure standby when the steering wheel is not turned.

3. Check the standby pressure at the pressure tap (C) for the steering system. Pressure tap (C) is part of the steering control manifold. The steering control manifold is mounted on the outside of the right frame behind the suspension cylinder.Note: The pressure gauge needs to withstand the maximum pressure from the steering piston pump.

4. Operate the engine at HI IDLE. Check the pressure without turning the steering wheel. The pressure setting of the flow compensator valve is 2000 kPa (290 psi) to 3600 kPa (522 psi).

5. If the pressure needs to be adjusted, stop the engine.

6. Remove cap (4) from setscrew (5) on flow compensator valve (7) .

7. Loosen locknut (3) of flow compensator valve (7) .

8. With an allen wrench, rotate setscrew (5) clockwise by 1/4 turn in order to raise the pressure. Rotate setscrew (5) counterclockwise by a 1/4 turn in order to lower the pressure. Each 1/4 turn of setscrew (5) changes the pressure approximately 414 kPa (60 psi). Refer to Illustration 8 in order to view the location of setscrew (5) .

9. Repeat Steps 1 through 8 until the pressure setting is correct.If the pressure cannot be adjusted, check flow compensator valve (8). The spool may be sticking. Replace the entire pressure and flow compensator valve (7) if the spool or the bore is damaged. Refer to Illustration 8 in order to view the location of flow compensator valve (8) .

10. Remove the test equipment.

MARYGAR

770G and 772G Off-Highway Truck: Piston Pump (Steering, Fan) - Test and Adjust 2012-12-05T14:34:00-08:00 Rating: 4.5 Diposkan Oleh: Unknown