Steering Gear: Description and Operation

NOTE: The power steering gear should NOT be serviced or adjusted. If a malfunction or oil leak occurs, the complete steering gear should be replaced.

If a steering gear boot needs to be replaced due to damage, refer to Tie Rod Boot for proper procedure.

The power steering system consists of these four major components. Power Steering Gear, Power Steering Pump, Pressure Hose, and Return Line. 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 which directs oil from the pump to either side of the integral rack piston.

Road feel is controlled by the diameter of a torsion bar which initially steers the vehicle. As required steering effort increases, as in a turn, the torsion bar twists, causing relative rotary motion between the rotary valve body and the valve spool. This movement directs oil behind the integral rack piston, which, in turn, builds up hydraulic pressure and assists in the turning effort.

The drive tangs on the pinion mate loosely with a stub shaft to permit manual steering control to be maintained if the drive belt on the power steering pump should break. However, under these conditions, steering effort will be increased.