BUCKET AS-SEVERE SERVICE ROCK 3967586 - Caterpillar

Illustration 1 g00627373
(1) Pump drive (2) Hoist pump (3) Inlet side (4) Outlet sidePerformance tests can be used for diagnosing poor performance and for finding the source of oil leakage inside the hydraulic system.
Problem: The hoist pump makes noise and the cylinder rods do not move evenly. Also, there are air bubbles in the oil.
Probable Cause
The low pressure relief valve in the hoist control valve opens at low oil pressure.
The high pressure relief valve in the hoist control valve opens at low oil pressure.
There is a loose connection in the oil line on inlet side (3) of hoist pump (2) .
The hoist pump (2) is worn.Problem: The temperature of the oil is hot.
Probable Causes
The viscosity of the oil is incorrect.
The low pressure relief valve in the hoist control valve opens at low oil pressure.
The high pressure relief valve in the hoist control valve opens at low oil pressure.
The hoist pump (2) is worn.
There is a restriction in an oil passage.
The load on the system is too high.Problem: The output of the hoist pump is too low.
Probable Cause
The oil level of the hydraulic tank (torque converter, hoist, and brake section) is too low.
The viscosity of the oil is incorrect.
The hoist pump (2) is worn.Problem: The pressure of the oil is low.
Probable Cause
The low pressure relief valve in the hoist control valve opens at low oil pressure.
The high pressure relief valve in the hoist control valve opens at low oil pressure.
The hoist pump (2) is worn.
An O-ring seal failed in the hydraulic system.