KIT-SEAL 2567092 - Caterpillar

Illustration 1 g06351523
Location of the steering pump
(1) Fan drive pump
(2) Current adjustment screw
(3) Steering pump
(4) Pump drive
(5) Displacement solenoid
(6) High-pressure cutoff valve
(7) Pressure and flow compensator valve
(8) Minimum angle stop screwSteering pump (3) is part of a double piston pump group. Fan drive pump (1) is the other part of the pump group. Both pumps are variable displacement piston pumps. A charging pump is located between the steering pump and the fan drive pump. The charging pump is used to keep both pumps supplied with oil. The steering pump is at the front bottom section of pump drive (4). The pump drive is on the right-hand frame rail near the rear of the flywheel housing.The steering pump operates only when the engine is running. The pump provides the necessary flow of oil to the steering accumulators. The Chassis ECM controls the flow of oil from the steering pump by energizing displacement solenoid (5).The Chassis ECM will analyze the sensor inputs for the accumulator pressure and the engine speed. The Chassis ECM will send 0 mA to 650 mAs to the solenoid. Between 0 mA and 100 mAs, the steering pump is at the maximum displacement and at the maximum flow. Between 600 mAs and 650 mAs, the steering pump is at the minimum displacement and at the minimum flow.Displacement solenoid (5) moves a spool in pressure and flow compensator valve (7) to control the flow of pump output pressure to the actuator piston (minimum angle). The actuator piston (minimum angle) will move the swashplate to the position of minimum flow. Current adjustment screw (2) controls the minimum current that is required to start destroking the pump.If the accumulator pressure sensor does not function properly, high-pressure cutoff valve (6) will control the maximum pressure within the steering system. The high-pressure cutoff valve controls the system pressure by controlling the flow of pump output pressure to the actuator piston (minimum angle). When the system pressure is at the maximum, high-pressure cutoff valve (6) will send oil to the actuator piston (minimum angle). The actuator piston (minimum angle) will move the swashplate to the position of minimum flow.Minimum angle stop screw (8) is located near pressure and flow compensator valve (7). The maximum angle stop screw is on the other side of the pump.
Illustration 2 g02007333
Sectional view of the steering pump
(7) Pressure and flow compensator valve
(8) Minimum angle stop screw
(9) Swashplate
(10) Piston
(11) Maximum angle actuator piston
(12) Maximum angle stop screw
(13) Rotary group
(14) Impeller (charge pump)
(15) Minimum angle actuator piston
(16) Drive shaft
(A) Fan drive section of the pump
(B) Steering pump sectionNote: The left side is the fan drive pump. The right side is the steering pump.Oil from the hydraulic tank enters the pump in the port below impeller (14) for the charge pump. Impeller (14) is driven by drive shaft (16) which is attached to pump drive (4). The charge pump keeps the steering pump and the fan drive pump full of oil.The large spring that is located around actuator piston (11) holds swashplate