DIAGRAM-WIRING 2W0872 - Caterpillar

Illustration 1 g00849964
Steering System Hydraulic Schematic (1) Steering control valve. (2) Left steering cylinder. (3) Right steering cylinder. (4) Dual check valve. (5) Pressure reducing valve. (6) Fan motor. (7) Right neutralizer valve. (8) Left neutralizer valve. (9) Oil cooler. (10) Fan control valve. (11) Pilot control valve. (12) Pressure control and selector valve. (13) Steering pump. (14) Hydraulic tank. (15) Fan pump. The pilot circuit controls the movement of the valve spool in steering control valve (1). Pressure oil from the fan pump (15) flows to pressure control valve (12) .While the engine is running, oil flows from hydraulic tank (14) to hydraulic fan pump (15). The fan drive pump is a piston type pump.Part of the oil flows from the pump to the fan drive motor and the oil cooler. The hydraulic fan motor is a fixed displacement bent axis motor. The rest of the oil flows through an oil line, past a check valve and into pressure control and selector valve (12) .The oil pressure is reduced to 3300 400 kPa (480 60 psi). The pilot oil then flows to the inlet of pilot valve (11) .Pilot oil pressure is supplied by steering pump (13) if the hydraulic fan pump fails. The pilot oil then flows into control valve (1). Next, the oil flows to pressure reducing and selector valve (5) .The reduced pressurized oil flows to the inlet of pilot control valve (11).