PUMP GP-GOV, FUEL INJ & TFR 4W8295 - Caterpillar

Illustration 1 g01278259
Partial hydraulic schematic (1) Motor for rotation of the work tool (2) Auxiliary control valve (medium pressure) (3) Extend solenoid valve (4) Retract solenoid valve (5) Pilot manifold (6) Auxiliary pump (7) Pilot filter (8) Pilot pump (9) Hydraulic oil cooler (10) Return filter (11) Hydraulic tankNote: The auxiliary control valve (medium pressure) does not influence the proportional solenoid valve for negative flow control.Pilot pump (8) supplies oil to pilot manifold (5). When the hydraulic activation lever is moved to the UNLOCK position, pilot oil flows from pilot manifold (5) to solenoid valves: (3) and (4) .When the left joystick slide control is moved FORWARD, the machine ECM sends a signal to the extend solenoid for the auxiliary control valve (medium pressure) (3). Pilot oil flows to the bottom of auxiliary control valve (2). The pilot oil will shift the control valve spool to the UPWARD position. This allows oil from auxiliary pump (6) to flow through the auxiliary control valve (medium pressure) (2) to motor (1) for clockwise rotation. Return oil flows through hydraulic oil cooler (9), through the return filter (10) and back to hydraulic tank (11). The working pressure for rotation is limited by the main relief valve.When the left joystick slide control is moved BACKWARD, the machine ECM sends a signal to the retract solenoid for the auxiliary control valve (medium pressure) (4). Pilot oil flows to the top of the auxiliary control valve (medium pressure) (2). The pilot oil will shift the control valve spool to the DOWNWARD position. This allows oil from auxiliary pump (6) to flow through the auxiliary control valve (medium pressure) (2) to motor (1) for counterclockwise rotation. Return oil flows through hydraulic oil cooler (9), through the return filter (10) and back to hydraulic tank (11). The working pressure for the work tool is limited by the main relief valve.