Steering: Description and Operation

- Oil pump is belt-driven from the engine to discharge oil under pressure.
- Oil under pressure is controlled by the oil pump in response to engine speed and is delivered to control valve via hose A.
- When the steering wheel is turned, control valve connected to the pinion shaft activates to form an oil flow circuit corresponding to the rotation direction of the steering wheel. Oil will then be delivered to chamber A or B via pipe A or B.
- Oil in chamber A or B acts on rack pinion to produce the force required to move rack shaft to the left or the right. This helps reduce the effort required to operate the steering wheel.
- Movement of rack piston in turn causes oil in the other chamber to return to tank via pipe A or B, control valve and hose B.
- If the hydraulic system becomes inoperative, the steering shaft will then be connected to the pinion shaft mechanically via control valve. Thus, the steering shaft can act as one similar to a manual steering system to move the rack and pinion.
- To control the maximum oil pressure setting, relief valve is built into the oil pump to release excess oil pressure.