RADIATOR GP 9Y8932 - Caterpillar

Illustration 1 g03344776
Hydraulic schematic for the steering system (1) Left steering cylinder (2) Right steering cylinder (3) Brake release cylinder (4) Steering release diverter valve (5) Check valve (6) Pressure tap for the brake release system (7) Brake release sequence valve (8) Line to parking brakes (9) Steering control valve (10) Connection for recovery hook type brake release system (11) Line relief and make-up valve (12) Line relief and make-up valve (13) Implement and steering neutralizer valve (14) Parking brake oil pressure switch - electronic transmission control (15) Parking brake oil pressure switch - remote control light (16) Shuttle valve (17) Load sensing valve (18) Steering pilot control valve (19) Pressure tap for the parking brake and the pilot system (20) Relief valve (21) Parking brake control valve (22) Line to parking brakes (23) Flow control valve (24) Steering relief valve (25) Spool (26) Steering system pressure tap (27) Check valve (28) Left neutralizer valve (29) Check valve (30) Right neutralizer valve (31) Orifice (32) Hydraulic oil cooler (33) Pressure tap for the steering pilot system (34) Steering pilot pressure reducing valve (35) Selector and pressure control valve (36) Secondary steering diverter valve (if equipped) (37) Check valve (38) Line from the implement lift circuit (39) Primary steering flow switch (if equipped) (40) Pilot oil pressure reducing valve (41) Hydraulic tank (42) Portable hydraulic pump quick connect coupler (43) Line to brake accumulator charging valve (44) Secondary steering pump (if equipped) (45) Breaker relief valve (46) Portable hydraulic pump quick connect coupler (47) Brake and pilot pump (48) Steering pump (49) Implement pump (50) Hydraulic oil filters (51) Check valveThe pilot circuit controls the movement of spool (25) in steering control valve (9) .With the engine running, oil is drawn from hydraulic tank (41) by brake and pilot pump (47) .Brake and pilot pump (47) supplies pilot oil through check valve (51) to pilot oil pressure reducing valve (40). Part of the oil also flows to the brake accumulator charging valve through line (43) .Pilot oil flows from pressure reducing valve (40) through check valve (27) to selector and pressure control valve (35) and implement and steering neutralizer valve (13) .While brake and pilot pump (47) is supplying oil to the pilot system, selector and pressure control valve (35) blocks the flow of alternate oil into the steering pilot system.If brake and pilot pump (47) fails, or pilot oil is unavailable, selector and pressure control valve (35) allows alternate pilot oil to flow into the steering pilot system from the lift cylinders. When oil is unavailable, from the lift cylinders, selector and pressure control valve (35) allows alternate pilot oil to flow into the steering pilot system from steering control valve (9) .Pilot oil flows through implement and steering neutralizer valve (13) to the hydraulic pilot circuit and through steering pilot pressure reducing valve (34) to steering pilot control valve (18). Implement and steering neutralizer valve (13) diverts oil flow to hydraulic tank (41) when the operator station