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