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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin. |
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| NOTICE |
|---|
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "AVSpare Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on AVSpare products. Dispose of all fluids according to local regulations and mandates. |
| Required Tools | ||
| Part Number | Description | Qty |
| 1U-5796 | Pressure Differential Gauge Group | 1 |
| 4C-4890 | Hydraulic Test Group | 1 |
- Lower the bucket or any work tools to the ground. Stop the engine.
- Install the steering frame lock.
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| Illustration 1 | g00280787 |
Steering Frame Lock | |
- Turn the steering wheel to the left and to the right in order to release any steering system pressure.
- Slowly loosen the hydraulic tank filler cap in order to release any residual pressure. Then, tighten the filler cap.
- Disconnect signal line (2) from the compensator valve.
 | |
| Illustration 2 | g00281546 |
Cab has been removed for photographic clarity Steering/Pilot Pump (1) Pressure tap. (2) Signal line. | |
- Connect the 1U-5796 Pressure Differential Gauge Group to pressure tap (1). Connect the 1U-5796 Pressure Differential Gauge Group between signal line (2) and the compensator valve.
- Start the engine and run the engine at low rpm. Allow the hydraulic oil to reach normal operating temperature. Check for hydraulic oil leaks.
- Increase the engine speed to a high rpm.
- Turn the steering wheel all the way to the right or to the left. While the steering wheel is slowly turned, take a pressure reading. The reading on the pressure gauge is the margin pressure. Margin pressure is the difference between discharge pressure of the steering/pilot pump and the signal pressure from the metering pump. The margin pressure should be 2500 kPa (365 psi).
- If the pressure reading is too low or too high, the flow compensator spool must be adjusted.
Reference: For the correct adjustment procedure, refer to the following procedure.
Adjustment Procedure for the Pressure and Flow Compensator Valve (Steering)
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| Illustration 3 | g00281377 |
Cab has been removed for photographic clarity Location of the Compensator Valve | |
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| Illustration 4 | g00915908 |
Compensator Valve (3) Adjustment screw for the pressure compensator. (4) Spring. (5) Pressure compensator spool. (6) Plug. (7) Adjustment screw for the flow compensator. (8) Flow compensator spool. | |
The high pressure stall test will indicate whether the pressure compensator valve needs an adjustment. The margin pressure test and/or the low pressure standby test will indicate whether the flow compensator valve needs an adjustment.
| NOTICE |
|---|
When the compensator is rebuilt, make sure that the pressure compensator adjustment is backed out to a low pressure setting before the engine is started. Otherwise, severe pump and system damage can result. |
Pressure Compensator Spool
Adjustments to the pressure compensation spool should only be made after completing the procedures in the Testing and Adjusting, "Steering System Pressure (High Pressure Stall) - Test". If the high pressure stall test indicates the need for an adjustment, use the following procedure:
- Lower the bucket or any work tools to the ground. Stop the engine.
- Install the steering frame lock.
- Turn the steering wheel to the left and to the right in order to release any steering system pressure.
- Slowly loosen the hydraulic tank filler cap in order to release any residual pressure. Then, tighten the filler cap.
- Remove the lockwire and the seal from the adjusting screw. Turn adjusting screw (3) clockwise in order to increase the pressure setting. Turn adjusting screw (3) counterclockwise in order to decrease the pressure setting.
- Start the engine and check the pressure. The correct pressure setting is 22800 ± 350 kPa (3305 ± 50 psi).
- When the pressure setting is adjusted correctly, stop the engine. Replace the lockwire and the seal on the adjusting screw.
Note: After you perform the adjustment procedure, recheck the margin pressure.
Flow Compensator Spool
Adjustments to the flow compensation spool should only be made after completing the procedures in the Testing and Adjusting, "Piston Pump (Steering) Margin Pressure - Test and Adjust". If the margin pressure test indicates the need for an adjustment, use the following procedure:
- Lower the bucket or any work tools to the ground. Stop the engine.
- Install the steering frame lock.
- Turn the steering wheel to the left and to the right in order to release any steering system pressure.
- Slowly loosen the hydraulic tank filler cap in order to release any residual pressure. Then, tighten the filler cap.
- Remove plug (6). Turn adjusting screw (7) clockwise in order to increase the pressure setting. Turn adjusting screw (7) counterclockwise in order to decrease the pressure setting.
- Start the engine and check the pressure. The correct pressure setting is 2500 ± 100 kPa (360 ± 15 psi).
- When the pressure setting is adjusted correctly, stop the engine. Replace plug (6) .
Note: After you perform the adjustment procedure, recheck the margin pressure.