PLATE-WEAR 1434340 - Caterpillar

Illustration 1 g01344882
Schematic of Check and Relief Valve for the Steering Cylinders (1) Servo cylinder (2) Right cylinder port to servo cylinder (3) Crossover relief valve for right turns (4) Check valve (5) Pilot passage to valve spool for right turn (6) Port to right turn port on steering metering pump (7) Drain port (8) Port to left turn port on steering metering pump (9) Pilot passage to valve spool for left turn (10) Check valve (11) Crossover relief valve for left turns (12) Left servo pilot system makeup valve (13) Drain from pressure reducing valve (14) Passage to pressure reducing valve (15) Right servo pilot system makeup valve (16) Left cylinder port to servo cylinder (CC) Pilot oil (UU) Tank oilThe check and relief valve for the steering cylinders sends oil to the servo pilot system. This protects the servo pilot system from high pressure. The system changes to a nonservo system in the event of a failure of the servo cylinder or of the hydraulic lines for the servo system.When the steering wheel is not being turned, oil from the pressure reducing valve flows through passage (14) to makeup valves (12) and (15). Oil from the makeup valves flows through left cylinder port (16) and through right cylinder port (2) to the servo cylinder. Oil also flows to pilot operated check valves (10) and (4) and crossover relief valves (11) and (3). The pilot operated check valves are open while the servo pilot system has pressure. The crossover relief valves will open only when the pressure in the pilot system rises about the setting of the crossover relief valve. Refer to Testing and Adjusting, "Relief Valve (Steering Cylinder Crossover) - Test and Adjust" for the setting of the crossover relief valves. Oil flows through the pilot operated check valves. The oil flows to pilot passages (9) and (5), and then to the ends of the valve spool in the steering control valve.Oil also flows through ports (8) and (6) to the left turn port and