SLEEVE 1168528 - Caterpillar

Illustration 1 g00981385
Hydraulic schematic for the steering system (1) Steering cylinder (2) Line relief and makeup valve for the head end of the steering cylinder (3) Line relief and makeup valve for the rod end of the steering cylinder (4) Steering neutralizer valve for a left turn (5) Steering neutralizer valve for a right turn (6) Spool (7) Secondary steering pump (8) Load sensing shuttle valve (9) Spool (10) STIC steering pilot valve (11) Spool (12) Implement and steering neutralizer valve (13) Check valve (14) Check valve (15) Pilot oil pressure reducing valve (16) Steering system pressure tap (17) Steering relief valve (18) Secondary steering diverter valve (19) Steering control valve (20) Hydraulic oil cooler (21) Line to the implement pilot circuit (22) Pilot system pressure tap (23) Check valve (24) Steering pump (25) Implement pump (26) Breaker relief valve (27) Selector and pressure control valve (28) Line to the parking brake oil pressure reducing valve (29) Pilot and braking pump (30) Hydraulic oil filters (31) Hydraulic tank (32) Line to the braking systemNote: Illustration 1 shows a machine with the secondary steering system. Machines without the secondary steering system will not have secondary steering pump (7) and secondary steering diverter valve (18) .The high pressure circuit provides the high pressure oil for steering cylinder (1) .With the engine running, oil is drawn from hydraulic tank (31) by steering pump (24). Steering pump (24) supplies oil to steering control valve (19). Oil supplied to steering control valve (19) flows through spool (9) to spool (6) .When pilot oil moves spool (6) the high pressure oil is directed to steering cylinder (1). When a right turn is made, the pressure oil flows to the rod end of steering cylinder (1). When a left turn is made, the pressure oil flows to the head end of steering cylinder (1) .Oil displaced from the steering cylinder when a turn is made returns through spool (6) and steering control valve (19) to hydraulic oil cooler (20). The return oil flows through hydraulic oil cooler (20) and hydraulic oil filters (30) to hydraulic tank (31) .The hydraulic oil cooler has an orifice that bypasses the oil cooler. If the oil is cold or if the oil cooler is blocked, the oil will flow through the orifice and return to the hydraulic tank.