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Hydraulic oil pressure can remain in the hydraulic system on this machine after the engine and pump have been stopped. Serious injury can result if this pressure is not released before any service is done on the hydraulic systems. In order to prevent possible injury, release the hydraulic system pressure before working on any fitting, hose, or hydraulic component. Lower all attachments to the ground before service is started. If the hydraulic system must be serviced, tested, or adjusted with the attachment in the raised position, the attachments and lift cylinders must be supported properly. Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made. |
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High hydraulic system pressure. To avoid personal injury, do not remove any hydraulic system lines, taps, or parts until all pressure has been relieved. |
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| NOTICE |
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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. |
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Keep all parts clean from contaminants. Contamination of the hydraulic system with foreign material will reduce the service life of the hydraulic system components. To prevent contaminants from entering the hydraulic system, always plug or cap the lines, fittings, or hoses as they are disconnected. Cover any disassembled components and clean them properly before assembly. Clean the hydraulic system properly after any major component exchange or especially after a component failure, to remove any contamination. |
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| Illustration 1 | g01076336 |
| Required Tools | ||||
|---|---|---|---|---|
| Tool | Item | Part Number | Description | Qty |
| A | A1 | 6V-4143 | Coupler | 4 |
| A2 | 6V-3989 | Fitting | 2 | |
| A3 | 8T-0860 | Pressure Gauge ( 40000 kPa (5800 psi)) |
2 | |
| A4 | 177-7860 | Hose As | 2 | |
- Open the right access door (1) .
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| Illustration 2 | g01076348 |
- Attach Tooling (A) to the test ports of the right conveyor pump and the left conveyor pump.
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| Illustration 3 | g01078857 |
Top view of the pumps | |
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| Illustration 4 | g01078865 |
Bottom view of the left forward relief valve and right forward relief valve (2) Right forward relief valve (3) Left forward relief valve | |
- Start the engine and run the engine at low idle.
Note: Stall the conveyors in order to perform the following tests.
- Activate the parking brake.
- Run the engine at high idle.
Note: The oil in the hydraulic system must be at an operating temperature of approximately 38 °C (100 °F).
- Move the feeder switch from the OFF position to the MANUAL position.
- Observe the pressure gauges. The pressure should be approximately 31025 ± 2070 kPa (4500 ± 300 psi).
- If the pressure is not within the specification 31025 ± 2070 kPa (4500 ± 300 psi), replacement of the relief valve is necessary.
- Move the feeder switch to the OFF position.
- Run the engine at low idle.
- Stop the engine.
- Remove the faulty relief valve.
- Install the new relief valve.
- Tighten the relief valve to the following torque 165 ± 15 N·m (120 ± 10 lb ft).
- After the replacement is made, repeat Step 3 through Step 7 in order to recheck the pressure reading.
- After the relief valve has been made, move the feeder switch to the OFF position.
- Run the engine at low idle.
- Stop the engine.
- Remove Tooling (A) from the test ports.
- Repeat Step 2 through Step 19 for the left forward relief valve and the right forward relief valve.