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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 attachments have been lowered, 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 Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates. |
When any test is made of a machine system, the hydraulic oil should be at 38 °C (100 °F).
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| Illustration 1 | g01128498 |
| Required Tools | ||||
|---|---|---|---|---|
| Tool | Item | Part Number | Description | Qty |
| A | A1 | 177-7860 | Hose As | 2 |
| A2 | 6V-4143 | Quick Connect Couplers | 4 | |
| A3 | 6V-3989 | Fittings | 2 | |
| A4 | 8T-0855 | Pressure Gauges | 2 | |
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| Illustration 2 | g01127002 |
Propel Pump (1) Swashplate control (2) Locknut (3) Threaded piston rod (4) X1 and X2 taps (5) Electronic displacement control | |
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| Illustration 3 | g01127004 |
Propel Pump (1) Swashplate control (3) Threaded piston rod (4) X1 and X2 taps (5) Connector for the electronic displacement control (6) Pressure tap (7) Pressure tap | |
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| Illustration 4 | g01351837 |
Disconnect hose assembly (8) and hose assembly (10) from pressure release solenoid valve (9). Plug the hose assemblies. Cap the fittings on pressure release solenoid valve (9) .
- Use the following procedure before you perform the testing and adjusting:
- Apply the parking brake.
- Place the propel control lever in neutral.
- Disconnect the connector for the electronic displacement control (5) .
- Raise the front of the machine and the rear of the machine at least 152.4 mm (6 inch) above the ground. Support the machine on jack stands.
- Apply the parking brake.
- Install a cross over hose between X1 and X2 taps (4). This equalizes the oil pressure on each side of the servo piston.
- Install two tooling (A) to pressure taps (6) and (7) .
- Start the engine. Operate the engine at high idle.
- Record the pressures on the gauges. The pressure readings must be identical.
- If the readings are not identical, the neutral position of the piston must be adjusted. Loosen locknut (2). Use an allen wrench to turn threaded piston rod (3). Turn threaded piston rod (3) clockwise or turn the piston rod counterclockwise until the pressure readings on pressure taps (6) and (7) are identical.
- Stop the engine.
- Tighten locknut (2). Remove tooling ( A) from pressure taps (6) and (7). Remove the cross over hose between X1 and X2 taps (4) .
- Reconnect the electrical connector (5) .
Note: The cross over hose has a minimum diameter of 6 mm (0.24 inch). The cross over hose must withstand a minimum pressure of 5000 kPa (725 psi).
- Connect hose assembly (8) and hose assembly (9) to the pressure release solenoid valve.
- Raise the machine and remove the blocks.
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| Illustration 5 | g01351837 |
Remove the plug from hose assembly (8) and hose assembly (10). Remove the caps from the fittings on pressure release solenoid valve (9). Connect hose assembly (8) and hose assembly (10) to pressure release solenoid valve (9).
Raise the front of the machine and the rear of the machine at least 152.4 mm (6 inch) above the ground. Remove the jack stands and lower the machine to the ground.