VALVE GP-RELIEF 1198396 - Caterpillar

Sudden movement of the machine or release of oil under pressure can cause serious injury to persons on or near the machine.To prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic system.
Refer to Systems Operation, Testing and Adjusting, "Machine Preparation for Troubleshooting" before you begin the test.
Illustration 1 g00655138
Hydraulic Pump and Oil Lines for Cushion-Hitch (1) Supply oil line (2) Pump outlet line (3) Drain oil line (4) Hydraulic pump (5) Supply line for the implement and steeringWhen the piston pump is in operation, some of the oil from the pistons in the pump does flow through pump outlet line (2) into the hydraulic system. The pump oil that does not flow into the hydraulic system flows into the pump body for lubrication to the parts that move. The oil is leakage oil. The leakage oil flows through a drain oil line (3) from the pump to supply oil line (5) for the implement and steering pumps.When there is an increase in the pressure of the oil from the pump, the amount of leakage oil increases. When the parts in the pump get worn, the amount of oil leakage increase. The amount of leakage oil through drain oil line (3) is an indication of the condition of the pump.Perform the oil leakage test according to the following steps:
When a hydraulic line is disconnected from the cushion-hitch pump, make sure to keep the disconnected end of the hydraulic line above the level of the cushion-hitch pump. This will prevent hydraulic oil from draining out of the body of the cushion-hitch pump while the engine is not running.
Make sure that the hydraulic oil tank is filled with hydraulic oil. Start the engine. Operate the scraper bowl until the temperature of the hydraulic oil is 63°C (145°F) to 68°C (155°F).
Make sure that the cushion-hitch control switch is in the LOCKDOWN position. Turn off the engine.
Disconnect the end of drain line (3) from the connection that is upstream of supply line (5). Place the disconnected end of drain line (3) into a large can. Install a 6V-9828 Cap Assembly onto the open connection in place of drain line (3) .
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.
Start the engine. Operate the engine at high idle. Move the cushion-hitch control switch to the CUSHION RIDE position. Leave the cushion-hitch control switch in the CUSHION RIDE position for the duration of this step. Wait for 5 seconds. Move the disconnected end of drain line (3) into another empty can for 30 seconds. After 30 seconds, move the disconnected end of drain line (3) back into