PUMP GP-GEAR 3182590 - Caterpillar

LEFT TURN Position
When the machine is turned to the left, the steering control valve operates in a similar manner.For a left turn, pilot oil enters pilot port (16). Pressure oil from pump inlet port (13) flows through passage (23). The oil then flows past directional spool (2). From directional spool (2), the oil flows out of steering cylinder port (4).The pressure oil then flows to the rod end of the steering cylinder on the left side of the machine. The oil also flows to the head end of the steering cylinder on the right side of the machine.At the same time, the return oil flows from the head end of the steering cylinder on the left side of the machine. The oil also flows from the rod end of the steering cylinder on the right side of the machine. This causes the machine to articulate to the left.Crossover Relief Valve for the Steering Cylinders
Illustration 9 g03488476
View of steering control valve
(1) Crossover Relief Valve for the Steering Cylinders
Illustration 10 g03488499
Schematic for the Steering Control Valve
(1) Crossover Relief Valve for the Steering Cylinders
Illustration 11 g03488526
Crossover Relief Valve for the Steering Cylinders
(2) Screw
(3) Jam nut
(4) Spring
(5) Spring chamber
(6) Sleeve
(7) Holes
(8) Valve face
(9) Passage
(10) Poppet for the relief valve
(11) Drain hole
(12) Face of sleeve
(13) Passage
(14) Valve face
(15) Valve seatThe crossover relief valve for the steering cylinders relieves shock loading in the steering system. The crossover relief valve operates when the steering system is in neutral or when the steering system is articulating the machine.Steering cylinder pressure is sensed in passages (9) and (13) of the steering control valve. Steering cylinder pressure is also sensed on valve faces (8) and (14).When the steering cylinders are moved by external steering forces, the pressure in passages (9) and (13) can increase suddenly.A pressure increase in passage (9) acts on valve face (8). If the pressure is greater than the valve setting, poppet (10) moves left. This pressure causes spring (4) to compress. The pressure is relieved to passage (13) through holes (7).If the pressure in passage (13) is greater than the pressure setting of the crossover relief valve, the pressure acts on valve face (14). The pressure also acts on the face of sleeve (12).Sleeve (6) and poppet (10) move to the left against spring (4). The pressure in passage (13) is relieved to passage (9) through holes (7).Spring chamber (5) is connected to the hydraulic oil tank through drain hole (11).The pressure setting of the crossover relief valve for the steering cylinders is adjustable.Reference: For additional information on the adjustment procedure for the crossover relief valve, refer to the Service Manual module for Testing and Adjusting, "Relief Valve (Steering Cylinder Crossover) - Test and Adjust" for the machine that is being serviced.Back up Relief Valve for the Steering System
Illustration 12 g03490601The backup relief valve for the steering system is on the right side of the steering control valve.
Illustration 13 g03490756
Schematic for the Steering Control Valve
(1) Back up Relief Valve for the Steering System
Illustration 14 g03886457
Back up Relief Valve for the