Power Steering Troubleshooting

General Auto Repair

Power steering is a system for reducing the steering effort on vehicles by using an external power source to assist in turning the roadwheels.

Most power steering systems work by using the common hydraulic or the less common electrical system to assist in turning the vehicle's wheels. The hydraulic pressure is usually provided by a gerotor or rotary vane pump driven by the vehicle's engine. A double-acting hydraulic cylinder applies a force to the steering gear, which in turn the pumps employed are of the positive displacement type, the flow rate they deliver is directly proportional to the speed of the engine. This means that at high engine speeds the steering would naturally operate faster than at low engine speeds. Because this would be undesirable, a restricting orifice and flow control valve are used to direct some of the pump's output back to the hydraulic reservoir at high engine speeds. A pressure relief valve is also used to prevent a dangerous build-up of pressure when the hydraulic cylinder's piston reaches the end of the cylinder.



Some modern implementations, which can be found in high end sports or luxury cars, also include an electronic pressure relief valve which can reduce the hydraulic pressure in the power steering lines as the vehicle's speed increases (this is known as variable assist power steering). Wikipedia:Power Steering

This is general trouble shooting information. This article is not intended to be specific to any unique situation or individual vehicle configuration. The purpose of this Trouble Shooting information is to provide a list of common causes to problem symptoms.

Rattle or Chucking Noise

• Pressure hoses touching engine parts: Adjust to proper clearance
• Loose Pitman shaft: Adjust or replace if necessary
• Tie rods ends or Pitman arm loose: Tighten and check system
• Rack and pinion mounts loose: Tighten all mounting bolts
• Free play in worm gear
• Loose sector shaft or thrust bearing adjustment
• Free play in pot coupling
• Worn shaft serrations

Growl in Steering Pump

• Excessive pressure in hoses: Restricted hoses
• Scored pressure plates
• Scored thrust plates or rotor
• Extreme wear of cam ring

Rattle in Steering Pump

• Vanes not installed
• Vanes sticking in rotor

Swish noise in Pump

• Defective flow control valve

Groan in Steering Pump

• Air in fluid
• Poor pressure hose connection: Tighten and check, replace if necessary

Squawk When Turning

• Damper "O" ring on valve spool cut

Moan or Whine in Pump

• Pump shaft bearing scored: Replace bearing and fluid
• Air in fluid or fluid level low
• Hose or column grounded: Check and replace if necessary
• Cover "O" ring missing or damaged
• Valve cover baffle missing or damaged
• Interference of components in pump
• Loose or poor bracket alignment: Correct or replace if necessary

Hissing When Parking

• Internal leakage in steering gear: Check valved assembly first

Chirp in Steering Pump

• Loose or worn power steering belt: Adjust or replace if necessary

Buzzing When Not Steering

• Noisy pump
• Free play in steering shaft bearing
• Bearing loose on shaft serrations

Clicking Noise in Pump

• Pump slippers too long
• Broken slipper springs
• Excessive wear or nicked rotors
• Damaged cam contour

Poor Return of Wheel

• Wheel rubbing against turn signal
• Flange rubbing steering gear adjuster
• Tight or frozen steering shaft bearing
• Steering gear out of adjustment
• Sticking or plugged spool valve
• Improper front end alignment
• Wheel bearings worn or loose
• Ties rods or ball joints binding: Check and replace if necessary
• Intermediate shaft joints binding
• Kinked pressure hoses: Correct or replace if necessary
• Damaged valve lever
• Sector shaft adjusted too tight
• Worm thrust bearing adjusted too tight
• Reaction ring sticking in cylinder
• Reaction ring sticking in housing head
• Steering pump internal leakage
• Steering gear-to-column misalignment
• Lack of lubrication in linkage: Service front suspension
• Lack of lubrication in ball joints: Service front suspension

Increased Effort When Turning Wheel Fast Foaming, Milky Power Steering Fluid, Low Fluid Level or Low Pressure

• High internal pump leakage
• Power steering pump belt slipping: Adjust or replace if necessary
• Low fluid level: Check and fill to proper level
• Engine idle speed to low: Adjust to correct setting
• Air in pump fluid system
• Pump output low
• Steering gear malfunctioning

Wheel Surges or Jerks

• Low fluid level: Check and fill to proper level
• Loose fan belt: Adjust or replace if necessary
• Insufficient pump pressure
• Sticky flow control valve
• Linkage hitting oil pan at full turn: Replace bent components

Kick Back or Free Play

• Air in pump fluid system
• Worn poppet valve in steering gear
• Excessive over center lash
• Thrust bearing out of adjustment
• Free play in pot coupling
• Steering gear coupling loose on shaft
• Steering disc mounting bolts loose: Tighten or replace if necessary
• Coupling loose on worm shaft: Tighten or replace if necessary
• Improper sector shaft adjustment
• Excessive worm piston side play
• Damaged valve lever
• Universal joint loose: Tighten or replace if necessary
• Defective rotary valve

No Power When Parking

• Sticking flow control valve
• Insufficient pump pressure output
• Excessive internal pump leakage
• Excessive internal gear leakage
• Flange rubs against gear adjust plug
• Loose pump belt: Adjust or replace if necessary
• Low fluid level: Check and add proper amount of fluid
• Engine idle too low: Adjust to correct setting
• Steering gear-to-column misaligned

No Power, Left Turn

• Left turn reaction seal "O" ring worn
• Left turn reaction seal damaged/missing
• Cylinder head "O" ring damaged

No Power, Right Turns

• Column pot coupling bottomed
• Right turn reaction seal "O" ring worn
• Right turn reaction seal damaged
• Internal leakage through piston end plug
• Internal leakage through side plugs

Lack of Effort in Turning

• Left and/or right reaction seal sticking in cylinder head: Replace

Wanders to One Side

• Front end alignment incorrect
• Unbalanced steering gear valve

Low Pressure Due to Steering Pump

• Flow control valve stuck or inoperative
• Pressure plate not flat against cam ring
• Extreme wear of cam ring: Replace and check adjustments
• Scored plate, thrust plate or rotor
• Vanes not installed properly
• Vanes sticking in rotor slots
• Cracked/broken thrust or pressure plate

General Auto Repair

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