Power Steering Pump: Testing and Inspection

HISSING NOISE IN STEERING GEAR
^ Improperly installed intermediate shaft boot.
^ Grounded power steering lines.
^ Improperly sealed Supplemental Inflatable Restraint processing holes in steering column.

Important
^ There is some noise in all power steering systems. One of the most common is a hissing sound when the steering wheel is turned and the vehicle is not moving. This noise will be most evident when fuming the wheel while the brakes are applied. Some hissing noise is normal under these conditions.
^ Do not replace the valve unless the hissing noise is extremely objectionable. A replacement valve will also have a slight noise and may not correct the condition. When diagnosing a hissing noise complaint, inspect all steering hoses to ensure they are not touching grounded to other parts of the vehicle.

RATTLE IN RACK AND PINION
^ Pressure hose touching other parts of vehicle grounded.
^ Loose tie rod ends.
^ Loose rack and pinion gear attachments.
^ Rack and pinion gear rack bearing preload below minimum.
^ Tie rods contacting air baffles or underbody components.

GROANING OR GROWLING NOISE IN STEERING PUMP
^ Grounded power steering lines.
^ Scored pressure plate, thrust plate, or rotor.
^ Worn cam ring.
^ Low pressure relief reservoir cap.
^ Restricted fluid lines high back pressure.
^ Air ingestion in return line.
^ Damaged flow control valve.
^ Low fluid level.
^ Loose pump mounting bolts.

RATTLE NOISE IN STEERING PUMP
^ Damaged pump rotor and/or vanes.
^ Damaged pump bearings.

SWISHING NOISE IN STEERING
^ Damaged flow control valve.

WHINING NOISE IN STEERING PUMP
^ Pump shaft bearing scored.
^ Scored pressure plate or thrust plate.
^ Damaged cam ring, rotor, or vanes.

POOR STEERING WHEEL RETURNABILITY
^ Incorrect front wheel alignment.
^ Loose or binding intermediate shaft coupling.
^ Binding tie rod ends.
^ Damaged upper strut mount bearing.
^ Binding ball joints.
^ Steering wheel rubbing against turn signal housing.
^ Tight or frozen steering column bearings.
^ Excessive rack and pinion gear rack bearing preload.
^ Sticking spool valve.

MOMENTARY INCREASE IN EFFORT WHEN TURNING WHEEL FAST TO RIGHT OR LEFT
^ High internal spool valve or steering gear leakage.
^ Sticking or damaged pinion spool valve.
^ Insufficient pump pressure.
^ Low fluid level.

STEERING WHEEL SURGES OR JERKS
^ Insufficient pump pressure.
^ Low fluid level.
^ Air in power steering system.
^ Sticking flow control valve.
^ Sticking pinion spool valve.
^ Belt worn or incorrect tension.
^ Incorrect power steering fluid.

STEERING WHEEL KICKBACK
^ Air in power steering system.
^ Low fluid level.
^ Loose rack and pinion gear attachments.
^ Missing check valve in pressure port of gear.
^ Loose intermediate shaft coupling.
^ Loose tie rod ends.

HARD STEERING OR LACK OF ASSIST
ESPECIALLY DURING
PARKING/TURNING/STEERING WHEEL
^ Magnasteer system malfunction Refer to Diagnostic Aids.
^ Intermediate shaft coupling damaged or worn.
^ Tight steering column bearings.
^ Sticking flow control valve.
^ Insufficient pump pressure.
^ Air in power steering system.
^ Low fluid level.
^ Excessive internal pump leakage.
^ Excessive internal rack and pinion leakage.
^ Check for diagnostic trouble codes in ride control system Refer to Electronically Controlled Suspension.

FOAMING POWER STEERING FLUID

Important
^ This can be caused by air in the fluid. Check for leak and correct. Bleed the system. Extremely cold temperatures will also cause air bubbles in the system if the fluid level is low.

LOW PRESSURE DUE TO STEERING PUMP
^ Seized or inoperative flow control valve.
^ Worn or improperly installed pressure or thrust plate.
^ Cracked or brokers thrust or pressure plate.
^ Worn cam ring, rotor, or vanes.
^ Vanes sticking in rotor slots.
^ High internal pump leakage.