CIRCUIT BREAKER AS 1712205 - Caterpillar

Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible personal injury, do the following procedure prior to servicing the machine.
1. Release the pressure in the hydraulic system as follows:a. Move the machine to a smooth horizontal location. Move away from working machines and personnel, and lower the hitch and/or implements to the ground.b. Permit only one operator on the machine. Keep all personnel either away from the machine or in view of the operator.c. Activate the parking brake.d. Stop the engine.e. Move the hydraulic control levers to all positions to release the pressure in the implement hydraulic system.f. Carefully loosen the filler cap on the hydraulic oil tank to release the pressure in the tank.g. Be sure all hydraulic pressure is released before any fitting, hose or component is loosened, tightened, removed or adjusted.h. Tighten the filler cap on the hydraulic tank. The pressure in the system has now been released, and lines or components can be serviced.2. Drain the oil from the steering hydraulic oil tank. The capacity of the steering hydraulic oil tank is 35 liters (9 U.S. gal). 3. Disconnect hose assemblies (2) and (3) from steering control unit (1). 4. Remove the cab air filter housing.5. Use two persons to support steering control unit (1), and remove bolts (4) and (6).6. Lower the steering control unit, and loosen the bolt that fastens the steering column shaft to the steering control unit shaft. Remove the steering control unit. The weight of the steering control unit is approximately 36 kg (80 lb). The following steps are for installation of the steering control unit.7. Use two persons to support steering control unit (1). Align the splines, and install the steering control unit shaft in the steering column shaft. Tighten the bolt that holds the steering control unit shaft in the steering column shaft.8. Position steering control unit (1) on the cab firewall, and install bolts (4) and (6).9. Install the cab air filter housing.10. Connect hose assemblies (2) and (3) on steering control unit (1).11. Remove plug (5) from the steering control unit. Fill the steering control unit with oil to the correct level. See "Steering Control Mechanism" in the Operation & Maintenance Manual for the correct filling procedure.12. Fill the steering hydraulic oil tank with oil to the correct level. See the Operation & Maintenance Manual.