Steering: Description and Operation

Power Steering System Description and Operation

Notice: Refer to Clutch Hydraulic System Lubricant Notice in Service Precautions.

Notice: Refer to Air in the Power Steering System Notice in Service Precautions.

Notice: Refer to Power Steering Hose Disconnected Notice in Service Precautions.

The power steering system consists of 3 components: the power steering pump, the power steering fluid reservoir, and the power steering rack and pinion gear. The power steering pump is a vane-type pump providing hydraulic pressure for the system and is powered by the engine. It draws on the power steering fluid reservoir, which in turn is connected to the power steering gear. A pressure-relief valve inside the flow control valve limits the pump pressure. The power steering rack and pinion gear has a rotary control valve which directs hydraulic fluid coming from the power steering pump to one side or the other side of the rack piston. The integral rack piston is attached to the rack. The rack piston converts hydraulic pressure to a linear force which moves the rack to the left or the right. The force is then transmitted through the inner and the outer tie rods to the steering knuckles, which turn the wheels.

Power Steering Pump Description
The pump has a remote fluid reservoir. A pressure-relief valve inside the flow control valve limits pump pressure.

Seal Replacement
Lip seals, which seal the rotating shafts, are used on the driveshaft of the pump. This type of seal requires special treatment. When leakage occurs in this area, always replace the seal after inspecting and thoroughly cleaning the sealing surfaces. If the corrosion in the lip seal contact zone is slight, clean the surface of the shaft with a crocus cloth. Replace the shaft only if the leakage cannot be stopped by first smoothing the shaft with the crocus cloth.

Power Steering Gear Description

Notice: Refer to Steering Gear Preload Adjustment Notice in Service Precautions.

Notice: Refer to Power Steering Hose Disconnected Notice in Service Precautions.

The power rack and pinion steering system has a rotary control valve which directs the hydraulic fluid coming from the hydraulic pump to one side or the other side of the rack piston. The integral rack piston is attached to the rack. The rack piston converts hydraulic pressure to a linear force which moves the rack left or right. The force is then transmitted through the inner and the outer tie rods to the steering knuckles, which turn the wheels.

If hydraulic assist is not available, manual control is maintained. However, under these conditions, more steering effort is required. The movement of the steering wheel is transferred to the pinion. The movement of the pinion is then transferred through the pinion teeth, which mesh with the teeth on the rack, causing the rack to move.

A vane-type pump provides hydraulic pressure for the system.

The boot and rack guide, the rack bearings, and the valve and pinion assembly are no longer serviceable on this vehicle. They must be replaced as whole units.