1 steering service. 2 tire wear diagnosis – excess toe-in excessive toe-in causes the outside...
TRANSCRIPT
1
Steering Service
Steering Service
2
Tire wear diagnosis – excess toe-inTire wear diagnosis – excess toe-in
• Excessive toe-in causes the outside edges of the tire to wear at an accelerated rate.
• When the wheels toe in the outside edge of the tires are being dragged slightly sideways as the tires roll.
• The excess heat created by this dragging melts the tread rubber.
• Excessive toe-in causes the outside edges of the tire to wear at an accelerated rate.
• When the wheels toe in the outside edge of the tires are being dragged slightly sideways as the tires roll.
• The excess heat created by this dragging melts the tread rubber.
3
Tire wear diagnosis – excess toe-outTire wear diagnosis – excess toe-out
• Abnormal wear caused by toe-out causes the inside edges of the tire to wear unevenly.
• If the front wheels have excessive toe-in or toe-out rapid and uneven wear will destroy both front tires.
• Excess toe-in / toe-out does not cause pull or vibration.
• Abnormal wear caused by toe-out causes the inside edges of the tire to wear unevenly.
• If the front wheels have excessive toe-in or toe-out rapid and uneven wear will destroy both front tires.
• Excess toe-in / toe-out does not cause pull or vibration.
4
Feathered edge wearFeathered edge wear
• Uneven wear caused by excessive toe-in or toe-out causes the tread blocks to wear unevenly.
• The wear pattern is called ‘feathered’ and appears as rounded on one edge of the tread block and square off at the opposite edge.
• Feathered edge wear can be felt by running your hand across the surface – in one direction it feels smooth and in the opposite direction it feels rough.
• Uneven wear caused by excessive toe-in or toe-out causes the tread blocks to wear unevenly.
• The wear pattern is called ‘feathered’ and appears as rounded on one edge of the tread block and square off at the opposite edge.
• Feathered edge wear can be felt by running your hand across the surface – in one direction it feels smooth and in the opposite direction it feels rough.
5
Visual inspectionVisual inspection
• Incorrect toe angle can be cause by a number of steering and suspension problems.
– Bent or worn tie rods– Bent control arms– Worn ball joints– Worn control arm bushings– Loose steering rack / bushings– Worn idler arm
• Incorrect toe angle can be cause by a number of steering and suspension problems.
– Bent or worn tie rods– Bent control arms– Worn ball joints– Worn control arm bushings– Loose steering rack / bushings– Worn idler arm
6
Tie rod end inspectionTie rod end inspection
• Both inner and outer tie rod ends are inspected by grapping a hold of the tie rod and pushing up/down and inward/outward.
• Any play in the tie rod will require replacement of the tie rod end.
• Both inner and outer tie rod ends are inspected by grapping a hold of the tie rod and pushing up/down and inward/outward.
• Any play in the tie rod will require replacement of the tie rod end.
Grasp the tie rod here
7
Tie rod replacementTie rod replacement
• Before loosening the jamb nut count the number of exposed threads on the tie rod.
• When the new tie rod end is installed with the same number of exposed threads the toe adjustment should be close to it’s original position.
• Before loosening the jamb nut count the number of exposed threads on the tie rod.
• When the new tie rod end is installed with the same number of exposed threads the toe adjustment should be close to it’s original position.
• If the steering arm is made of forged steel the tie rod end can be separated form the steering arm using a flat side of a ball peen hammer.
• If the steering arm is made of forged steel the tie rod end can be separated form the steering arm using a flat side of a ball peen hammer.
Exposed threads
8
Tie rod separatorTie rod separator
• If the tie rod end is to be replaced a pickle fork can be used to separate the tie rod end from the steering knuckle.
• If the steering arm is made of aluminum or stamped steel a screw type separator will be required.
• If the tie rod end is to be replaced a pickle fork can be used to separate the tie rod end from the steering knuckle.
• If the steering arm is made of aluminum or stamped steel a screw type separator will be required.
Images courtesy OTC corp.
9
Replacing inner tie rod ends on rack & pinionReplacing inner tie rod ends on rack & pinion
• The outer tie rod end can remain attached to the steering arm.
• Loosen the jamb nut then unscrew the tie rod from the outer end.
• Remove jamb nut, boot clamps and boot.• Bend the locking plate with a flat chisel• Unscrew the tie rod end from the steering
rack using a special tie rod end removal socket.
• The outer tie rod end can remain attached to the steering arm.
• Loosen the jamb nut then unscrew the tie rod from the outer end.
• Remove jamb nut, boot clamps and boot.• Bend the locking plate with a flat chisel• Unscrew the tie rod end from the steering
rack using a special tie rod end removal socket. Image courtesy OTC corp.
10
Inner tie rod end removal toolsInner tie rod end removal tools
• Universal tie rod end tool sets are available with adapters that fit a variety of vehicles.
• Universal tie rod end tool sets are available with adapters that fit a variety of vehicles.
Image courtesy OTC corp.
11
Replacing inner tie rod endsReplacing inner tie rod ends
• Adapters are needed on this style tie rod to get to the flats behind the inner joint.
• This style inboard boot clamp is non reusable .
• Adapters are needed on this style tie rod to get to the flats behind the inner joint.
• This style inboard boot clamp is non reusable .
Non-reusable boot clamp
Flats behind inner joint
Note: portions of the boot have been
removed for this photo
Image courtesy General Motors corp.
12
Steering wheel off centerSteering wheel off center
• Generally if there is something bent in the steering / suspension system it will effect one side more than the other.
• If the toe adjustment is off on just one side of the vehicle the driver will correct for it by steering the car.
• If the steering wheel is not at 12 O’clock when driving on a straight and level road there is unequal toe in the steering system.
• Generally if there is something bent in the steering / suspension system it will effect one side more than the other.
• If the toe adjustment is off on just one side of the vehicle the driver will correct for it by steering the car.
• If the steering wheel is not at 12 O’clock when driving on a straight and level road there is unequal toe in the steering system.
13
Diagnosis – loose steeringDiagnosis – loose steering
• Most steering systems have a small amount of freeplay.
• Freeplay can be defined as movement of the steering wheel that does not produce movement at the tires.
• Freeplay is best checked on alignment rack with the turn plates unlocked.
• Two technicians are needed – one sitting in the car moving the steering wheel and the other under the car observing the steering linkage.
• Most steering systems have a small amount of freeplay.
• Freeplay can be defined as movement of the steering wheel that does not produce movement at the tires.
• Freeplay is best checked on alignment rack with the turn plates unlocked.
• Two technicians are needed – one sitting in the car moving the steering wheel and the other under the car observing the steering linkage.
14
Determining the location of freeplayDetermining the location of freeplay
• Hold the steering coupler or pinion shaft with an appropriate tool and have your assistant wiggle the steering. If there is excessive freeplay the problem is in the column or coupler.
• Observe the rack as your assistant wiggles the steering. If the rack moves side to side the rack bushings or mounts are worn.
• Hold the steering coupler or pinion shaft with an appropriate tool and have your assistant wiggle the steering. If there is excessive freeplay the problem is in the column or coupler.
• Observe the rack as your assistant wiggles the steering. If the rack moves side to side the rack bushings or mounts are worn.
15
Determining the location of freeplayDetermining the location of freeplay
• If the pinion shaft moves but there is no motion in the tie rods the freeplay is inside the rack.
• If the tie rods move back and forth but the tires do not move the problem is in the outer tie rod ends or wheel bearings.
• If the pinion shaft moves but there is no motion in the tie rods the freeplay is inside the rack.
• If the tie rods move back and forth but the tires do not move the problem is in the outer tie rod ends or wheel bearings.
16
Freeplay in linkage type steeringFreeplay in linkage type steering
• Loose idler arm pivot bushings are a common problem in parallelogram type systems.
• Grab the idler arm and push up and down. The end of the idle arm should not move up or down more than ¼”.
• Push up and down and side to side on all the other ball and socket joints in the system. There should be nothing loose.
• Grab the steering coupler and rock the worm shaft back and forth. If there is motion in the worm shaft but the pitman arm does not move there is freeplay in the steering box.
• Loose idler arm pivot bushings are a common problem in parallelogram type systems.
• Grab the idler arm and push up and down. The end of the idle arm should not move up or down more than ¼”.
• Push up and down and side to side on all the other ball and socket joints in the system. There should be nothing loose.
• Grab the steering coupler and rock the worm shaft back and forth. If there is motion in the worm shaft but the pitman arm does not move there is freeplay in the steering box.
17
Adjusting the steering boxAdjusting the steering box
• Freeplay can be adjusted on a recirculating ball steering box.
• First separate the pitman arm from the center link.
• Center the steering wheel.• Loosen the lock nut.• Turn the Allen screw inward
¼ turn.• Turn the steering wheel from
9 O’clock to 3 O’clock .• The adjustment is correct
when a very slight resistance is felt as the steering passes through 12 O’clock.
• Freeplay can be adjusted on a recirculating ball steering box.
• First separate the pitman arm from the center link.
• Center the steering wheel.• Loosen the lock nut.• Turn the Allen screw inward
¼ turn.• Turn the steering wheel from
9 O’clock to 3 O’clock .• The adjustment is correct
when a very slight resistance is felt as the steering passes through 12 O’clock.
Jamb nutAdjuster
screw [Allen]
18
Diagnosis – fluid leaksDiagnosis – fluid leaks
• There should no lose of power steering fluid over time. If fluid needs to be added to the reservoir there is a leak somewhere in the system.
• Leakage in one of the rack seals may be contained in the rack boot. In normal operation the rack boots should be dry.
• Because of liability issues leaking racks, steering boxes and pumps are normally replaced rather than installing new seals.
• There should no lose of power steering fluid over time. If fluid needs to be added to the reservoir there is a leak somewhere in the system.
• Leakage in one of the rack seals may be contained in the rack boot. In normal operation the rack boots should be dry.
• Because of liability issues leaking racks, steering boxes and pumps are normally replaced rather than installing new seals.
19
Replacing hydraulic linesReplacing hydraulic lines
• Flair nut wrenches are needed to remove and replace P/S hoses.
• Flair nut wrenches are needed to remove and replace P/S hoses.
• Flair type ‘crows feet’ adapters are normally required in the tight confines surrounding the steering rack.
• Flair type ‘crows feet’ adapters are normally required in the tight confines surrounding the steering rack.
20
Why flare nut wrenches are neededWhy flare nut wrenches are needed
• The hose connector nuts are made of a soft metal.• When conventional wrenches are used the flats on
the nuts are damaged.
• The hose connector nuts are made of a soft metal.• When conventional wrenches are used the flats on
the nuts are damaged.
21
Replacing hydraulic linesReplacing hydraulic lines
• Plastic looms are located between the sub-frame/body and metal hydraulic lines to prevent abrasion.
• Rubber cushions are wrapped around rubber hydraulic lines where there may be contact with the unibody.
• Plastic looms are located between the sub-frame/body and metal hydraulic lines to prevent abrasion.
• Rubber cushions are wrapped around rubber hydraulic lines where there may be contact with the unibody.
22
Hard steering - diagnosisHard steering - diagnosis
• Possible causes– Loose power steering belt– Low fluid / fluid leak– Faulty power steering pump– Seized ball joints – strut bearings – tie rod ends– Faulty control valve – Blocked or restricted P/S hose – pinched metal
line
• Possible causes– Loose power steering belt– Low fluid / fluid leak– Faulty power steering pump– Seized ball joints – strut bearings – tie rod ends– Faulty control valve – Blocked or restricted P/S hose – pinched metal
line
23
Fluid levelFluid level
• Power steering should be checked with the fluid at 80o F.
• Most reservoirs have a dipstick in the cap with a hot and cold mark.
• To bring the fluid up to temperature turn the steering lock to lock several times with the engine running.
• Place a drop of fluid on a clean shop towel. The fluid should be clear and not appear burnt.
• The fluid in the reservoir should be free of air bubbles and foam.
• Power steering should be checked with the fluid at 80o F.
• Most reservoirs have a dipstick in the cap with a hot and cold mark.
• To bring the fluid up to temperature turn the steering lock to lock several times with the engine running.
• Place a drop of fluid on a clean shop towel. The fluid should be clear and not appear burnt.
• The fluid in the reservoir should be free of air bubbles and foam.
24
Hard steering - diagnosisHard steering - diagnosis
• With the vehicle raised off of the ground and the engine off turn the steering.– If the steering is harder to turn than normal
disconnect the tie rod ends from the steering arms.
– Turn the steering knuckle by hand – if it doesn’t move freely the ball joints or strut bushing are frozen.
• If the steering turns normally with the engine off but is hard to steer when driving on the road the problem is probably in the power assist system.
• With the vehicle raised off of the ground and the engine off turn the steering.– If the steering is harder to turn than normal
disconnect the tie rod ends from the steering arms.
– Turn the steering knuckle by hand – if it doesn’t move freely the ball joints or strut bushing are frozen.
• If the steering turns normally with the engine off but is hard to steer when driving on the road the problem is probably in the power assist system.
25
Hard steering - diagnosisHard steering - diagnosis
• If the belt]s] is OK and tensioned properly and the fluid level is normal a pressure test may be needed to further diagnose the problem.
• A P/S system tester combines a 0 – 3000 psi hydraulic gauge and a shutoff valve.
• The tester is connected between the pump and high pressure hose.
• If the belt]s] is OK and tensioned properly and the fluid level is normal a pressure test may be needed to further diagnose the problem.
• A P/S system tester combines a 0 – 3000 psi hydraulic gauge and a shutoff valve.
• The tester is connected between the pump and high pressure hose.
26
P/S pressure testP/S pressure test
• With the tester connected the pressure should be around 100 to 150 psi with no steering input and rise to about 1000 psi when the steering is turned to full lock.
• With the tester connected the pressure should be around 100 to 150 psi with no steering input and rise to about 1000 psi when the steering is turned to full lock.
Shutoff Valve0 – 3000 psi
gauge
High pressure
hose
Control valve
Accessory hose – part of
pressure tester set
27
P/S pressure testP/S pressure test
• With the tester connected the pressure should be around 100 to 150 psi with no steering input and rise to about 1000 psi when the steering is turned to full lock.
• With the tester connected the pressure should be around 100 to 150 psi with no steering input and rise to about 1000 psi when the steering is turned to full lock.
Gauge end connects to
pump
Valve end connects to
High pressure hose
Shutoff Valve
• With the shutoff valve closed the pressure should rise to about 1000 psi.
• If the pressure does not rise when the shutoff valve is closed the pump is faulty.
• With the shutoff valve closed the pressure should rise to about 1000 psi.
• If the pressure does not rise when the shutoff valve is closed the pump is faulty.
Image courtesy OTC corp.
28
• If the pressure rises to about 1000 psi when the valve is closed but does not rise as much when the valve is open and the steering is turned to full lock the fault lies inside the rack/steering box.
• If there is higher than specified pressure when the valve is open and there is
• If the pressure rises to about 1000 psi when the valve is closed but does not rise as much when the valve is open and the steering is turned to full lock the fault lies inside the rack/steering box.
• If there is higher than specified pressure when the valve is open and there is
P/S pressure testP/S pressure test
29
Pull to either side – self steeringPull to either side – self steering
• Generally a pull to the right or left is caused by an alignment or brake problem.
• A bad control valve however can cause a steering system to self steer.
• To check for a possible self steer raise the vehicle on a lift so the tires are off the ground.
• Center the steering a 12 O’clock.• Start the engine and watch the steering wheel.• If the steering wheel turns to either side the
control valve is faulty and the rack/box will have to be replaced.
• Generally a pull to the right or left is caused by an alignment or brake problem.
• A bad control valve however can cause a steering system to self steer.
• To check for a possible self steer raise the vehicle on a lift so the tires are off the ground.
• Center the steering a 12 O’clock.• Start the engine and watch the steering wheel.• If the steering wheel turns to either side the
control valve is faulty and the rack/box will have to be replaced.
30
Replacing the power steering pumpReplacing the power steering pump
• A new or remanufactured power steering pump does not usually come with a pulley.
• The pulley on the old P/S pump is transferred to the new P/S pump
• The P/S pump pulley is press fit to the pump shaft.
• A special tool set is needed to remove and replace the P/S pulley.
• A new or remanufactured power steering pump does not usually come with a pulley.
• The pulley on the old P/S pump is transferred to the new P/S pump
• The P/S pump pulley is press fit to the pump shaft.
• A special tool set is needed to remove and replace the P/S pulley.
31
Removing the pump pulleyRemoving the pump pulley
Pulley removal
tool
Pulley Installer
tool
Thrust bearing
Threads connect tool to pump shaft
Internal flange grips groove in hub
Sleeve presses against pump
shaft
Images courtesy OTC corp.
32
Removing the pump pulleyRemoving the pump pulley
• The pulley has a groove in it’s hub that the pulley removal tool engages.
• The pulley has a groove in it’s hub that the pulley removal tool engages.
Groove for removal tool
Image courtesy General Motors corp.
33
• Before removing the pulley from the old hub look to see how far the pump shaft extends outside the hub.
• Install the pulley on the new pump with the same amount of shaft protruding.
• Press fit pulleys can be repositioned to bring a misaligned belt back into pro
• Before removing the pulley from the old hub look to see how far the pump shaft extends outside the hub.
• Install the pulley on the new pump with the same amount of shaft protruding.
• Press fit pulleys can be repositioned to bring a misaligned belt back into pro
Installing the pump pulleyInstalling the pump pulley
34
Correcting excess toe-inCorrecting excess toe-in
• To correct the toe-in problem here both tie rods need to be made shorter.
• To correct the toe-in problem here both tie rods need to be made shorter.
Jamb nut Inner tie rod
Clamp
• Toe is adjusted by loosening the jamb nut then turning the inner tie rod until toe is correct.
• The outer boot clamp may need to be loosened to prevent boot twisting.
• Toe is adjusted by loosening the jamb nut then turning the inner tie rod until toe is correct.
• The outer boot clamp may need to be loosened to prevent boot twisting.
35
Correcting excess toe-outCorrecting excess toe-out
• To correct the toe-out problem here both tie rods need to be lengthened.
• To correct the toe-out problem here both tie rods need to be lengthened.
• If the steering rack is located ahead of the axle centerline the tie rods need to be shortened.
• If the steering rack is located ahead of the axle centerline the tie rods need to be shortened.
36
Rack and pinion
replacement procedure
Rack and pinion
replacement procedure
37
Lock the steeringLock the steering
• With the steering in a straight ahead position wrap the seatbelts through the steering wheel.
• Disconnect the battery.
• With the steering in a straight ahead position wrap the seatbelts through the steering wheel.
• Disconnect the battery.
38
Disconnect the tie rod endsDisconnect the tie rod ends
• If the rack is being replaced a pickle fork can be used to separate the tie rod end from the steering arm.
• If the rack is being replaced a pickle fork can be used to separate the tie rod end from the steering arm.
39
Remove outer tie rod endsRemove outer tie rod ends
• After disconnecting the tie rod from the steering arm unscrew the tie rod end from the inner tie rod.
• Count the number of turns so that the tie rod ends can be installed on the new rack in the same position.
• After disconnecting the tie rod from the steering arm unscrew the tie rod end from the inner tie rod.
• Count the number of turns so that the tie rod ends can be installed on the new rack in the same position.
Another way is to count the number of threads outboard of the jamb nut after the tie rod is removed
40
Disconnect steering couplerDisconnect steering coupler
• The coupler pinch bolt is a special bolt that should be labeled so that it is reinstalled in its original location.
• The coupler pinch bolt is a special bolt that should be labeled so that it is reinstalled in its original location.
• Lift the rubber boot that protects the steering coupler to gain access to the pinch bolt.
• Lift the rubber boot that protects the steering coupler to gain access to the pinch bolt.
41
Remove the hydraulic linesRemove the hydraulic lines
• Disconnect the supply and return lines.• The two smaller lines can stay attached to
the rack.
• Disconnect the supply and return lines.• The two smaller lines can stay attached to
the rack.
Return lineSupply line
42
Remove the rack mount boltsRemove the rack mount bolts
• The rack mount bolts are special bolts that should be labeled and reinstalled in their original position.
• The rack mount bolts are special bolts that should be labeled and reinstalled in their original position.
Rack mount bolt
43
Remove rack Remove rack • The rack can now be withdrawn through the wheel well.
• The rack can now be withdrawn through the wheel well.
44
Remove tie rod end lock nutsRemove tie rod end lock nuts
• With the rack removed from the vehicle the lock nuts can be removed easily.
• With the rack removed from the vehicle the lock nuts can be removed easily.
45
Pinion shaft notchPinion shaft notch • The pinion shaft is notched to insure that the coupler is installed at the correct depth and orientation.
• The pinion shaft is notched to insure that the coupler is installed at the correct depth and orientation.
46
Center the rack prior to installation.Center the rack prior to installation.
• Turn the pinion shaft all the way to the right and then turn to the left while counting how many turns.
• Turn the shaft to bask the right half that number and the rack should be centered.
• Turn the pinion shaft all the way to the right and then turn to the left while counting how many turns.
• Turn the shaft to bask the right half that number and the rack should be centered.
47
Reinstall the rackReinstall the rack
Note: Return line on this rack uses a
conventional hose connection with a
worm clamp.
Note: Return line on this rack uses a
conventional hose connection with a
worm clamp.
48
Connect the steering couplerConnect the steering coupler
• The notch in the pinion shaft must align with the hole for the pinch bolt.
• When the coupler is installed correctly the pinch bolt can be easily installed with your fingers.
• Do not hammer the pinch bolt into the coupler.
• The notch in the pinion shaft must align with the hole for the pinch bolt.
• When the coupler is installed correctly the pinch bolt can be easily installed with your fingers.
• Do not hammer the pinch bolt into the coupler.
Notch in pinion shaft
49
Install new O-rings on the hydraulic linesInstall new O-rings on the hydraulic lines
• A set of new o-rings are included in the remanufactured steering rack box.
• A set of new o-rings are included in the remanufactured steering rack box.
50
Connect tie rod endsConnect tie rod ends
• The tie rods ends should be threaded onto the inner tie rod end with the same number of turns that were recorded when they were removed from the old rack.
• The number of turns on the left and right side should be roughly equal.
• The tie rods ends should be threaded onto the inner tie rod end with the same number of turns that were recorded when they were removed from the old rack.
• The number of turns on the left and right side should be roughly equal.
51
Install copper pin and trim to lengthInstall copper pin and trim to length
• After trimming the cotter pin end is bent upward.• After trimming the cotter pin end is bent upward.
52
Top off PS fluidTop off PS fluid
• Before starting the engine fill the PS fluid reservoir.
• With the engine running top off the fluid level.
• With the engine running turn the steering all the way left and then all the way right to bleed the air out of the system.
• Shut the engine off and wait 15 to 20 minutes for the remaining air trapped in the system to rise to work it’s way out then repeat this process to purge any remaining air bubbles.
• Before starting the engine fill the PS fluid reservoir.
• With the engine running top off the fluid level.
• With the engine running turn the steering all the way left and then all the way right to bleed the air out of the system.
• Shut the engine off and wait 15 to 20 minutes for the remaining air trapped in the system to rise to work it’s way out then repeat this process to purge any remaining air bubbles.
53
AlignmentAlignment
• Any time the rack or tie rods are replaced the toe angles must be readjusted on an alignment machine.
• Besides correcting the toe angle the alignment will insure that the steering wheel is at 12 O’clock when the vehicle is driven straight.
• Any time the rack or tie rods are replaced the toe angles must be readjusted on an alignment machine.
• Besides correcting the toe angle the alignment will insure that the steering wheel is at 12 O’clock when the vehicle is driven straight.