Trade Catalogues

Below are links to common problems encountered with power steering - Click on the hyperlink to take you to your query

	Shudder
	Noise - squeal - rattle - thump - squawk - groan - growl - whine - swish
	No or Low Power Assist
	Poor Return of Steering Wheel
	Steering Wheel Jerks when turning
	Occasional increase in steering effort
	Slop or wonder in steering
	Loss of power steering fluid
	Bleeding procedures
	Other unusual problems.

Shudder - Shudder can be caused by a number of reasons the first things to look for are

1. BELT Check for

	Tension
	Glazing
	Oil contamination

2. HOSES - Hoses are designed to carry oil and DAMPEN SYSTEM NOISE. Incorrect hose fitment can cause excessive noise and shudder.

	Has it been changed
	Is it the correct hose.
	Has it gone hard

3. AIR - Shudder can be caused by air in the system causing the pump to cavitate.

Go to Air cavitation explanation

Go to bleeding procedure

4. OIL - Some vehicle are fitted with special oil to overcome inherent shudder problems - has the specified manufactures

oil been used Back to top

Noise - There is some noise in all power steering systems. This sound is most noticeable during slow speed parking, and when the steering wheel reaches the end of its travel.

Other noises can be caused by the following

1. Air

Is the Pump Cavitating ?. � Cavitation is caused by air bubbles in the oil. These can be formed by

	The inducing of air from external air leaks on the low pressure side of the pump (Note: Air can leak in without oil leaking out)
	Or the formation of air caused by pressure in the low pressure side dropping below the vaporisation point, when this is reached the liquid undergoes a phase change to a gas, creating "bubbles," or, more accurately, cavities, in the liquid.

Causes of Cavitation

	Twisted, loose, cracked or blocked inlet line
	Contamination - dirt and foreign material
	Damaged / blocked / incorrectly installed filters (inline and inside reservoir)
	Reservoir components
	Inner hose liner separation
	Reservoir cap "vent" plugged
	Incorrect oil

2. Squeal

	Pumps can often appear to be the source of the noise, but it is in fact coming from the belt. A quick test is to pour water on the drive belt if this eliminates or changes the sound you know that the noise is from the drive belt. Undo the drive belt and run the engine at the speed the noise was coming in, if the noise is still there you will have to look elsewhere. IE Belt tensioner bearing
	Check if pulleys are aligned - Rapid wear and noise can result if not.

3. Rattle

	Pressure hose touching other parts
	Loose pump pulley nut
	Incorrectly installed or sticking pump vanes
	Loose pump or steering gear mounts
	Loose steering linkages
	Incorrect high point adjustment

4. Thumping

Loose column or connections

Free play in worm and piston assembly

Knock in Bendix Box � Holden / Falcon

The knock mostly is NOT the box but coming from a cracked chassis mount - check for flex at the mount when the box is turned left to right.

5. Squawk

Cut dampener ""o"ring on spool valve

6. Groan

	Low Fluid level
	Air in the System - click here to go to air

7. Growl

	Restriction in steering gear or hoses
	Scored pump thrust plates and/or rotor
	Pump Cam ring worn

8. Whine

Pump shaft bearing or bush

9. Swish sound from pump

Defective flow control valve

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No or low power assist

Loose pump belt. (chirping or squeal)

( do not over-tighten or lever against pump as damage will occur)

Low power steering fluid in reservoir (groaning sound)

Major damage can be caused to the pump if it is run for to long with low or no oil.

	Incorrect Tyre Pressures
	Steering linkage / Column binding or seized.
	Steering gear adjustments too tight.
	Vehicle has not been overloaded ?
	Check steering column and or intermediate shaft for wear or binding.
	Does oil in reservoir smell hot or burnt ?

Sometimes the power steering oil supply will become hotter than the operating temperature and overheat.

This condition may result in an intermittent loss of power assist and also cause deterioration of the power steering

hoses and component seals.

Restricted hoses or ports � ( growling sound)

Blocked hoses are harder to determine unless a proper test of the system is performed.

Low pump output

Loose , glazed or Contaminated Drive belt

Internal leak in steering gear -

This can be caused by blown seals or Teflon rings or worn seal areas � steering components will need to be

removed for inspection and repair.

Stuck or blocked flow control valve - (swishing sound)

This condition will bypass fluid directly back to the pump and reduce output pressure.

A temporary fix is to run the engine at approx 2000RPM and turn the wheel hard to the stops a few times, this can

sometimes restore normal power assist BUT the pump will need servicing

Back to top

PooPoor return of steering wheel

Steering column binding

Check Column bushes / intermediate shaft universals and alignment

	Steering component seized or binding IE linkage or ball joints.
	Steering gear adjustments too tight.
	Excessive internal leakage in steering gear.
	Steering gear to column not aligned.
	Tyres under inflated.
	Sticking Spool (hydrostatic) valve
	Improper front wheel alignment.
	Back to top

Steering Wheel Jerks (pulses) when Turning

	Low fluid level.
	Loose, glazed or contaminated belt at pump.
	Sticky pump flow control valve.
	Engine idle too slow, air in system.
	Low pump pressure.
	Play in the pinion torsion bar pin or in the pinion spool pin.
	Steering components or linkage hitting obstruction. Back to top

Occasional increase in effort when turning

	Pump drive belt loose, glazed or oil contaminated.
	High internal leakage in gear.
	Low fluid level.
	Binding steering linkage & or component
	Engine idle to low
	Air in the system
	Low pump output Back to top

Slop or Wonder in the Steering

Check the following:

	Worn or damaged steering linkage or wheel bearings.
	Loose steering gear mounting.
	Improper high point adjustment of steering gear.
	Steering column coupling loose / worn.
	Loose sector shaft adjustment on gear.
	Loose thrust bearing preload adjustment.
	Air in fluid.
	Check for incorrect fitment of the coupling to the box or rack

Couplings must be fitted to the box / rack aligned in the centre position with the wheels in the straight ahead position.

If steering is erratic or suffers severe direct change � rack/box could have broken torsion rod or badly worn/broken torsion pin. Back to top

Loss of Power Steering Fluid:

If oil is everywhere it pays to clean the engine bay to find the source of the leak. Sometimes a hose can have a pin hole leak that shoots oil onto other components and can cause faulty diagnosis.

Fluid level Dropping, but no sign of leaks?

	Does the vehicle have Vacuum Idle-up?
	If YES � check idle-up switch in pump or rack for leaks

Fluid can be sucked into engine manifold and burnt. Back to top

Bleeding Procedure

	Inspect reservoir for foaming or air bubbles, if foaming or bubbles are seen, check for cracks or loose fittings. Look for oil level changes when engine is off versus engine on. If fluid level increases when the engine is shut off, there is an air pocket trapped in the steering gear. The increase may not be noticeable, depending on the size of the pocket.
	Bleed the steering gear (if there is a bleed screw at the top of the gear). With system at normal operating temperature and engine at proper idle speed or just above, open the bleed screw and wait until clean, clear oil begins to flow from the gear. Close the bleed screw and steer the vehicle completely from stop to stop. Turn off engine and allow oil to settle and repeat the bleeding operation three times, and recheck oil level in reservoir to make sure there is enough oil for the system to operate properly.
	If there is no bleed screw, with system at normal operating temperature and engine at idle speed or just above, turn the wheel from lock to lock a few times and turn off. Allow oil to settle and try again, do this 2 to three times and air should be expelled from the system.

NOTE leave the lid on the pump as trapped air escaping can blow oil out. Back to top

OTHER UN-USUAL PROBLEMS (RACKS)

Steering is heavy (no assist) and suddenly starts to work.

Main piston teflon can dislodge from piston groove and flap in and out of the groove with change of direction and oil flow.

Steering pulses when turning

Steering Wheel feels like it is pushing back when turning or steering is vague

Valve body pin in pinion is worn allowing valve body to float.

OTHER UN-USUAL PROBLEMS (BOXES)

Power Boxes - Steering slow or won't return to centre &/or no or low power assist

Toyota Power Box (or many others without bleeder). If customer complains about low (or no) power assist in one direction, or steering not wanting to return to centre - This can be caused by air at the top of the box. If it has a bleeder, bleed the box, if not turn vehicle with wheel off the ground lock to lock until air clears. Sometimes you have to let the vehicle sit for a number of hours.

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