Steering System Service

1
Steering System Service

• Chapter 66

2
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

3
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

4
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

5
Type of Fluid

• Power steering fluid is recommended in power
  steering systems
• Use manufacturer's recommended fluid

6
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

7
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

8
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

9
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

10
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

11
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

12
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

13
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

14
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

15
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

16
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

17
Steering Wheel Service

• Considerations
• Do not hammer on end of steering shaft when
  removing steering wheel
• Make alignment marks with centerpunch and hammer

18
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

19
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

20
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

21
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

22
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

23
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

24
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

25
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

26
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

27
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

28
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

29
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

30
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

31
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

32
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

33
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