PUMP GP-PISTON 4328159 - Caterpillar

Table 1
Required Tools
Part Number Description Required Amount
6V-3079 Pressure Hose Assembly 1
6V-4143 Coupler Assembly 2
198-4240 Digital Pressure Indicator 1 Note: Make sure that the filters and the screens are clean before you test any pressures. Make sure that the oil is at operating temperature before you perform this test.Note: Before you perform any tests, visually inspect the entire hydraulic system for oil leaks and for damaged components.
Personal injury or death can result from sudden machine movement.Sudden movement of the machine or the release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury before testing and adjusting the hydraulic system, perform the procedure in the Testing and Adjusting, "General Information" section.
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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products.Dispose of all fluids according to local regulations and mandates.
Illustration 1 g01258000
(1) High-pressure relief valve
(2) Low-pressure relief valve
(3) Hoist dual stage relief valve
(4) Hoist control valve Hoist dual stage relief valve (3) is part of the hoist control valve (4). The relief pressure for the RAISE position is controlled by high-pressure relief valve (1). The relief pressure for the LOWER position is controlled by low-pressure relief valve (2).Relief Valve Test (High Pressure)
Illustration 2 g02323816
(5) Pressure tap for high-pressure oil
Lower the dump body. Stop the engine.
Connect a hose assembly with an 8T-0860 Pressure Gauge ( 0 to 40000 kPa (0 to 5800 psi)) to pressure taps (5).
Start the engine. Operate the dump body repeatedly until the temperature of the hydraulic oil is above 38°C (100°F).
Run the engine at high idle and move the hoist control to the RAISE position.
After the dump body is fully raised, look at the gauge. Hold the hoist control in the RAISE position. The high-pressure gauge reading is the relief valve pressure setting of high-pressure relief valve (1). The correct pressure setting is 18950 520 kPa (2750 75 psi).
Illustration 3 g00531382
(1) High-pressure relief valve
(2) Low-pressure relief valve
(3) Hoist dual stage relief valve
(6) Nut
(7) Retainer
Loosen nut (6). Turn retainer (7) in order to adjust the setting of high-pressure relief valve (1).
When high-pressure relief valve (1) is correctly set, tighten nut (6). Relief Valve Test (Low Pressure)
Illustration 4 g02323853
(8) Pressure tap for low-pressure oil
Lower the dump body. Stop the engine.
Connect a hose assembly with an 8T-0856 Pressure Gauge ( 0 to 6000 kPa (0 to 870 psi)) to pressure tap (8).
Start the engine. Operate the dump body repeatedly until the temperature of the hydraulic oil is above 38°C (100°F).
Lower the dump body onto the truck frame. Note: The body down or up switch must be in the RAISE position before low-pressure relief valve (2) can be measured. If the body down or up switch is in