Stuck or inoperative flow control valve.

Replace or clean the valve.

Pressure plate is not flat against the cam ring.

Replace the pressure plate.

Extreme wear of the cam ring.

Replace the cam ring. Flush the system.

A scored pressure plate, thrust plate, or rotor.

1. Replace any scored parts.

If the rotor is scored, replace the rotor with a rotating group.

2. Flush the system.

Refer to Steering Gear Service in Power Steering Gear Unit Repair.

The vanes are sticking in the rotor slots.

Free the vanes by removing any burrs, varnish or dirt.

Improper installation of the vanes.

Properly install the vanes. Ensure that the radius edge is installed to the outside.

Air in the fluid.

Locate and repair the leak.

Low power steering fluid.

Add the necessary amount of power steering fluid.

The pump belt is slipping.

Refer to Drive Belt Replacement or Drive Belt Replacement in Engine Mechanical (5.0L, 5.7L, and 7.4L) or Drive Belt Replacement in Engine Mechanical (6.5L).

Damaged hoses or steering gear.

Replace any damaged parts.