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Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before testing and adjusting the power train. |
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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the work tools have been lowered to the ground, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand. |
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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, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates. |
- If the engine is still running, stop the engine.
- Remove four bolts (3) and washers.
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| Illustration 1 | g00798620 |
- Remove both footrests (1) .
- Remove floormat (2) .
- Remove six bolts (4) and washers.
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| Illustration 2 | g00798650 |
- Remove access panel (5) .
- Remove cap (7) from pressure override valve (6) .
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| Illustration 3 | g00836781 |
The pump is installed on the machine. | |
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| Illustration 4 | g00836782 |
The pump is removed from the machine for clarity. | |
- Mark the position of adjustment screw (9) .
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| Illustration 5 | g00836783 |
- Loosen locknut (8) .
- Turn adjustment screw (9) clockwise for one full turn in order to increase the POR pressure.
- Maintain the position of adjustment screw (9) while you tighten locknut (8) .
| NOTICE |
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If the adjustment screw bottoms out when you turn the adjustment screw clockwise, do not exceed a torque of 2 N·m (18 lb in). Damage to the valve could result if you exceed this torque. |
- Replace the access panel.
- Enter the machine.
- Fasten the seat belt.
- Start the engine.
- Use ET to set the machine in STALL TEST MODE. Refer to Testing and Adjusting, "Transmission Stall Test - Setup".
- Increase the engine speed to 1000 ± 50 rpm.
- Move the travel control to the FORWARD position and record both loop pressures. The pressure for the crossover relief valve should be 47500 ± 750 kPa (6900 ± 110 psi).
- Move the travel control to the REVERSE position and record both loop pressures. The pressure for the crossover relief valve should be 47500 ± 750 kPa (6900 ± 110 psi).
- Return the travel control to the HOLD position.
- Decrease engine speed to LOW IDLE.
- Stop the engine.
- Remove cap (10) of the crossover relief valve that is not within the specification. Remove the spring and the crossover relief valve.
The crossover relief valve for REVERSE is on the left side of the pump when you view the pump from the operator's seat. The crossover relief valve for FORWARD is on the right side of the pump when you view the pump from the operator's seat.
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| Illustration 6 | g00836785 |
The pump is installed on the machine. | |
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| Illustration 7 | g00836784 |
The pump is removed from the machine for clarity. | |
- Place crossover relief valve (11) into a vise.
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| Illustration 8 | g00798888 |
- Turn set screw (12) counterclockwise in order to loosen the set screw.
- Place retainer (13) of the crossover relief valve in a vise. Turn adjustment screw (14) in order to adjust the relief pressure. Turn the adjustment screw clockwise in order to increase the pressure or turn the adjustment screw counterclockwise in order to decrease the pressure. One full turn of the adjustment screw is approximately 6400 kPa (928 psi).
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| Illustration 9 | g00798915 |
- Tighten set screw (12) to a torque of 6.5 N·m (58 lb in).
Note: When you adjust the crossover relief valve in order to decrease the pressure, turn the adjustment screw for an additional one quarter turn past the estimated adjustment setting. Then, turn the adjustment screw clockwise for one quarter turn.
- Install crossover relief valve (11), spring (15) and cap (10). Tighten the cap to a torque of 160 ± 10 N·m (120 ± 7 lb ft).
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| Illustration 10 | g00836786 |
- Repeat Step 13 through Step 28 until the relief pressure is correct.
- Readjust the pressure override valve to the correct pressure setting. Refer to Testing and Adjusting, "Pressure Override Valve - Adjust".