TURBO GP-BASIC 2853253 - Caterpillar

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, "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.
Illustration 1 g01043845
(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)
Lower the dump body. Stop the engine.
Illustration 2 g00854722
Manifold for the hoist cylinder lines
(5) Pressure tap
Remove the protective cover from the pressure tap (5). Connect a hose assembly with an 8T-0860 Pressure Gauge ( 0 to 40000 kPa (0 to 5800 psi)) to pressure tap (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 and 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 19650 to 20685 kPa (2850 to 3000 psi).
Illustration 3 g00531382
(1) High pressure relief valve
(2) Low pressure relief valve
(3) Hoist dual stage relief valve
(6) Nut
(7) Retainer
If the pressure reading is not correct, loosen nut (6). Turn retainer (7) in order to adjust the setting of high pressure relief valve (1). Turn retainer (7) clockwise in order to increase the pressure setting and turn retainer (7) counterclockwise in order to decrease the pressure setting.
When high pressure relief valve (1) is correctly set, tighten nut (6).
Lower the dump body and stop the engine.
Remove the test equipment. Place the protective cover on the pressure tap. Relief Valve Test (Low Pressure)
Lower the dump body. Stop the engine.
Illustration 4 g00854724
Manifold for the hoist cylinder lines
(8) Pressure tap
Remove the protective cover from pressure tap (8). Connect a hose assembly with an 8T-0856 Pressure Gauge ( 0 to 6000 kPa (0 to