Steering: Description and Operation

DESCRIPTION
This vehicle is equipped with either standard power steering or speed-sensitive variable-assist power steering. Early production vehicles are equipped with speed-sensitive variable-assist power steering only, while later production vehicles are equipped with standard power steering only. The variable-assist feature on the early production vehicles is built into the power steering pump. Refer to Power Steering Pump for additional information on speed-sensitive variable-assist power steering.
The power steering system consists of these major components:
- Power Steering Pump
- POWER STEERING GEAR
- POWER STEERING FLUID RESERVOIR
- POWER STEERING FLUID SUPPLY HOSE
- POWER STEERING FLUID PRESSURE HOSE
- POWER STEERING FLUID RETURN HOSE
- POWER STEERING FLUID COOLER
- POWER STEERING FLUID COOLER TUBES

For information on the components, refer to their respective sections within this information.

OPERATION
Turning of the steering wheel is converted into linear travel through the meshing of the helical pinion teeth with the rack teeth. Power assist steering is provided by an open center, rotary type control valve.
It is used to direct oil from the power steering pump to either side of the integral steering rack piston.
Road feel is controlled by the diameter of a torsion bar which initially steers the vehicle. As steering effort increases as in a turn, the torsion bar twists, causing relative rotary motion between the rotary valve body and valve spool. This movement directs oil behind the integral rack piston, which in turn builds up hydraulic pressure and assists in the turning effort.
Refer to Power Steering Pump for information on the operation of the speed-sensitive variable assist power steering.