© © 2012 Delmar, Cengage Learning Steering System Service Chapter 66

© © 2012 Delmar, Cengage Learning

Steering System Service

Chapter 66


Objectives• Describe problems with steering system

components• Inspect the condition of the steering system• Explain different types of repairs that can be

made to the steering system• Describe repair procedures for rack-and-pinion

and parallelogram steering systems• Perform steering system repairs in a safe and

professional manner


Introduction• Normal use

– Steering parts remain separated by lubricants

• Seals are damaged and lubricants leak– Parts rub against each other

• Road hazards – Cause hard impacts to steering parts

• Belts and hoses can fail– Results in operational problems


Fluid Level Checks• Power steering fluid level

– Should be checked hot

– With engine idling: turn wheel several times in each direction

– Before shutting off engine: check fluid level


Type of Fluid• Power steering fluid is

recommended in power steering systems– Use manufacturer's

recommended fluid


Diagnosing Steering Problems and Noise Diagnosis

• Causes of steering and suspension problems– Play and looseness

– Incorrect height

– Wheels not aligned to specifications

• Causes of noise from steering system – Loose power steering belt

– Pump bypassing pressure

– Lack of fluid in power steering reservoir


Hard Steering and Tire Wear• Causes of hard steering

– Lack of steering fluid

– Binding in the steering linkage

– Steering gearbox problems

– Low tires

– Incorrect wheel alignment settings

• Steering and suspension problems – Often result in unusual tire wear

• Worn parts cause scalloped or gouged tire wear• Improper alignment adjustments cause tire wear


Steering Part Inspection and Steering Linkage Inspection

• Inspect steering system before wheel alignment– Inspect wheel bearings

• Wheel bearing is loose: wheel alignment equipment cannot make accurate readings

• Steering linkage inspection– Best way to discover looseness is dry park check

– Look for loose parts while observing the steering and suspension as wheels turn

– Steering linkage cab be inspected while vehicle is in air during lube inspection


Steering Gear Looseness• Causes of excessive steering wheel free play

– Worn steering linkage

– Worn flexible coupling at steering column

– Worn or misadjusted steering gear

• Steering wheel free play – Check with the engine off


Parallelogram Inspection• Important points

– Check sockets for looseness or damage to seal

– Idler arm movement can cause tire wear

– Small amount of movement where pitman arm attaches to steering linkage is often normal

– Inspect tie-rods for wear


Rack-and-Pinion Steering Linkage Inspection

• Important points– Feel for looseness by grasping the tie-rod

through bellows boot

– Should not be any looseness between inner tie-rod ball and socket

• If tie-rod is hanging down in its socket: it could be bound up


Steering Linkage Repairsand Idler Arm Replacement

• Steering linkage parts are locked together by wedging them against each other with “tapers”– When disassembling tapers to service or replace

parts, there are several ways to get them apart

• Idler arm replacement– Check to see if it one of the adjustable types

– Bump steer causes toe to change when going over bumps

• Causes tire wear


Pitman Arm Replacement• Important points

– Removal requires a special puller

– Must be replaced in the same position on the splines of the steering gear

– Check its position before removing it

– Pitman arms often have a “blind side”


Tie-Rod End Replacement• Characteristics and key points

– Tie-rod ends are threaded to provide a means of adjusting toe

– Measure old tie-rod assembly before disassembling

– Removing old tie-rod end: count the number of turns to remove it

– Before tightening tie-rod clamps: check condition and position


Rack-and-Pinion Tie-Rods• Inner tie-rod socket is held to ends of steering

rack– Several ways

• Jam nut• Special washer staked into flat area at end of rack• Roll pin is used to hold tie-rod to rack


Steering Wheel, Column, and Air Bag Service

• Removal of the steering wheel – Sometimes necessary

• Air bag service– Driver's side air bag has a clock spring or spiral

cable• Clock spring must be wound correctly and must be

“timed” to steering column• Clock spring has a certain amount of travel


Steering Wheel Service• Considerations

– Do not hammer on end of steering shaft when removing steering wheel

– Make alignment marks with centerpunch and hammer


Steering Column Service• Can be complicated

– Proper service manual should be consulted

• Causes of noises in steering column– Loss or damaged steering coupling

– Misalignment

– Bearing or horn ring that lacks lubricant

• Worn flex coupling – Causes looseness in the steering wheel


Steering Gear Service• Most common service is repair of fluid leaks

– Damage can be caused by collisions or potholes

• Steering gears – Occasionally rebuilt by technicians

• Recirculating ball and nut manual steering gears – Two adjustments to make

• Preload adjustment• High point


Manual Rack Service and Rack- and-Pinion Looseness

• Manual rack service– Steering wheel on rack-and-pinion must be

centered• Center of rack is hardened• Tie-rods are of different lengths: car steers to one

side farther than the other

• Rack- and-pinion looseness– Steering damper holds tension against rack

– Rack gear preload adjustment can be made• Rack is worn: tightening this adjustment can result

in binding steering at outsides during turns


Power Steering System Service• Includes:

– Repair and replacement of pump

– Hydraulic system flushing

– Seal replacement

– Belt and hose service

– Service and repairs to steering gear

– Reservoir service


Power Steering System Flushing

• Important points– Check condition of hoses

– Service life of rack-and-pinion: lengthened by changing steering fluid

– Commercial fluid exchange units are available

– Fluid can be exchanged without disconnecting hoses

– Shop does not have steering flusher: technician flushes steering system manually


Bleeding the System of Air• Air in steering system causes erratic operation

and/or a growling sound• Remove air from system

– Be sure tires are lifted off ground

– Fluid is warm: run engine at idle and cycle steering wheel from lock to lock several times

– Inspect for bubbles

– Some technicians bleed power steering air with the engine off


Power Steering Pump Replacement

• Major steps– Prior to removing

• Disconnect return hose to drain fluid

– Loosen and remove the belt• Easier if vehicle is on a lift

– Bracket must be removed from pump• Note bracket locations


Repairing Power Steering Pump Oil Leaks

• Integral reservoir – Sealed to pump with a large O-ring

– Seals are also located at the pump shaft and fittings for hoses

• Replacement of pump shaft seal – Requires removal of pulley

• Front seal leaks and there is sufficient space– Pulley can be removed without removing pump


Power Steering Pressure Diagnosis

• When pressure is low: there is noise and it is harder to steer the vehicle– Pressure varies: steering effort will be erratic

– Check belt tension first

– Pressure testing varies among manufacturers


Power Steering Pump Service• Defective power steering pumps

– Typically replaced with rebuilt pump

• Flow control valve service– Flow control valve and piston and spring will fall

out after fitting is removed

– Disassemble and inspect all parts

– When relief valve is mounted on outside of pump housing: use a new O-ring during reinstallation


Power Steering Hoses• Considerations

– System has two hoses• Pressure hose• Return hose

– Sometimes pressure hose has two different ends

– Look for signs of leakage or dampness at connections


Refilling the Power Steering System

• Major steps and considerations– Use correct fluid

– After refilling the system: run the engine and check for leaks

– Hoses that use O-rings: install new O-rings

– Bleed system of air


Power Steering Gear Service• Power steering failures

– Lack of power assist in one direction

– Leakage from steering gear

• Most shops buy rebuilt power steering gears• Rack-and-pinion steering

– More prone to problems • Weight has been cut

– Rack damage • Can be due to torsion bar bent from a hard impact

or serious leaks


Replacing Rack-and-Pinion Units

• Major steps and considerations– Sometimes grooves wear in control valve

housing

– Rebuilt units usually have a nickel-plated sleeve

– Remove steering shaft coupler first

– Remove roll pins with a punch and chisel

– There are usually four tubing connections into top of rack and pinion unit

• Special crowfoot flare socket might be helpful with removal


Variable Power Steering Service

• Problems can be mechanical or electrical– Mechanical problem: there will almost always be

noise or loss of power assist

– Electrical failure: power steering system goes back to operating on full-time power assist

• Refer to electrical troubleshooting procedure


Electronically Controlled Power Steering System Service

• Typical complaint: steering too easy or too hard– Perform a visual inspection

• Correct fluid levels• Check belt tension• Check electrical connections

– Connect a scan tool• Electrical defect: diagnostic trouble code will be

displayed

Documents

© © 2012 Delmar, Cengage Learning Steering System Service Chapter 66