WHEEL & TIRE GP 3728384 - Caterpillar

Illustration 1 g00529944
Hoist and brake gear pump
(1) Hoist pump section
(2) Brake pump section The hoist and brake gear pump is a two-section gear pump. Hoist pump section (1) and brake pump section (2) make up the hoist and brake gear pump.Oil from the hoist and brake hydraulic tank flows to the hoist and brake gear pump. Hoist pump section (1) then pumps oil to the hoist control valve. The hoist control valve will send pump oil to one of two locations. When the dump body is being raised or lowered, the hoist cylinders receive the oil. If the hoist is not being used, the oil flows to the oil cooling system for the rear brakes.Brake pump section (2) will send oil to two locations. Some of the oil is sent to the hoist proportioning solenoids on the hoist control valve. This is pilot oil that is used to move the spool in the hoist control valve. Most of the oil is sent to the parking and secondary brake valve. This oil is used to release the parking brakes on the rear wheels. There is a relief valve in the parking and secondary brake valve. When the pressure of the oil reaches the relief setting, the relief valve will open. Oil will be sent to the oil cooling system for the rear brakes.