PUMP GP-PISTON 3014678 - Caterpillar

Table 1
Tools Needed     Qty    
4C-4892 ORFS Fittings Group     1    
1U-5796 Pressure Differential Gauge Group     1    
8T-0861 Pressure Gauge (
0 to 60000 kPa (0 to 8700 psi))     1    
Hydraulic oil pressure can remain in the hydraulic oil system on this machine after the engine and pump have been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent possible injury, refer to the procedure in Testing and Adjusting Manual, "Release of Pressure in the Hydraulic System".When possible, the bucket must always be lowered to the ground before service is started. When it is necessary for the boom to be in the raised position while tests or adjustments are done, be sure that the boom, stick and bucket have correct support.Be sure the swing parking brakes and the travel parking brakes are on and the brake release lines are disconnected and plugged.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.
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.
Note: The load sensing signal may be decreased due to internal leakage. This test determines if the internal leakage is great enough to cause low power to the implements and/or travel.
Illustration 1 g00446023
Regulator Control Valve for the Implement Piston Pump (1) Load sensing signal pressure line (2) Pressure tap for load sensing signal pressure
Illustration 2 g00446024
Implement High Pressure Screens (1) Pressure tap for the main system pressure
Install a 1U-5796 Pressure Differential Gauge Group in pressure tap (2) and pressure tap (3). Either of the pressure taps (3) may be used. Connect the low pressure hose to pressure tap (2). Connect the high pressure hose to pressure tap (3). Connect the 8T-0861 Pressure Gauge to the second high pressure tap on the 1U-5796 Pressure Differential Gauge Group in order to measure the main system pressure.
Illustration 3 g00646763
Front control valve (4) Boom line relief valve
Remove the line relief valve (4) from the boom circuit. Install a used line relief valve into the circuit.
Start the engine.
Warm the oil to a temperature of 50 °C (122 °F). If the problem occurs at another temperature, warm the oil to the temperature that is required for the problem to occur. Note the hydraulic oil temperature. Refer to the Testing and Adjusting, "General Information" for the proper procedure for warming the hydraulic oil.Note: Do not stall the boom function while the oil is being warmed. Damage to the boom line