Measuring Wheel Alignment
Measuring Wheel AlignmentSteering and vibration complaints are not always the result of improper alignment. One possible cause is wheel and tire imbalance. Another possibility is tire lead due to worn or improperly manufactured tires. Lead is the vehicle deviation from a straight path on a level road without pressure on the steering wheel. Before performing any adjustment affecting wheel alignment, perform the following inspections and adjustments in order to ensure correct alignment readings:
^ Inspect the tires for the proper inflation and irregular tire wear.
^ Inspect the runout of the wheels and the tires.
^ Inspect the wheel bearings for backlash and excessive play.
^ Inspect the ball joints and tie rod ends for looseness or wear.
^ Inspect the control arms and stabilizer shaft for looseness or wear.
^ Inspect the steering gear for looseness at the frame.
^ Inspect the struts/shock absorbers for wear, leaks, and any noticeable noises.
^ Inspect the vehicle trim height.
^ Inspect the steering wheel for excessive drag or poor return due to stiff or rusted linkage or suspension components.
^ Inspect the fuel level. The fuel tank should be full or the vehicle should have a compensating load added.
Give consideration to excess loads such as tool boxes, sample cases, etc. If normally carried in the vehicle, these items should remain in the vehicle during alignment adjustments. Give consideration also to the condition of the equipment being used for the alignment. Follow the equipment manufacturer's instructions.
Satisfactory vehicle operation may occur over a wide range of alignment settings. However, if the setting exceeds the service allowable specifications, correct the alignment to the service preferred specifications.
Perform the following steps in order to measure the front and rear alignment angles:
1. Install the alignment equipment according to the manufacturer's instructions.
2. Bounce the front and the rear bumpers 3 times prior to checking the wheel alignment.
3. Measure the alignment angles and record the readings.
Important: When performing adjustments to vehicles requiring a 4-wheel alignment, set the rear wheel alignment angles first in order to obtain proper front alignment angles.
4. Adjust alignment angles to vehicle specification, if necessary.
Front Camber Adjustment
Tools Required
^ S A9140E Torque Angle Gage
Important: Rear wheel alignment angles must be set to correct specifications before front wheel alignment angles are adjusted.
1. Raise and support the vehicle.
2. Remove the wheel and tire assemblies.
3. Remove the strut to knuckle nuts and bolts. Discard the nuts and bolts.
4. If the strut has not been previously modified, perform the following procedure:
4.1. Disconnect the strut from the knuckle.
Important:
^ The strut mounting bracket consists of two layers of metal, file the inner layer no further than the slot in the outer layer.
^ If filing the strut, paint the exposed metal with primer.
4.2. If increasing negative camber, remove the material from the outside of the lower strut hole.
4.3. If decreasing negative camber, remove the material from the inside of the lower strut hole.
5. Loosely install the new strut to knuckle nuts and bolts.
6. Adjust the camber to specifications by moving the top of the wheel in or out as necessary.
Notice: Refer to Fastener Notice in Service Precautions.
7. Using the S A9140E, tighten the strut to knuckle nuts and bolts. Tighten
7.1. Tighten the nuts and bolts to 50 Nm (37 ft. lbs.).
7.2. Tighten the nuts and bolts to 100 Nm (74 ft. lbs.) plus an additional 30 to 45 degrees.
8. Install the wheel and tire assemblies.
9. Lower the vehicle.
10. Check the camber angles and adjust as necessary.
Front Toe Adjustment
Important:
^ Front wheel toe adjustment is performed with the steering wheel locked in the forward position.
^ Front toe is performed after rear toe and camber have been checked.
1. Position and lock the steering wheel with the vehicle with the wheels in the straight forward position.
2. Loosen both inner tie rod jam nuts.
Important: The inner tie rod must rotate freely from the boot seal surface. Do not allow the boot to rotate.
3. Loosen the inner tie rod seal to boot surface.
4. Use a wrench on the tie rod flats to increase or decrease the toe angle specifications.
Notice: Refer to Fastener Notice in Service Precautions.
5. Tighten the inner tie rod jam nuts.
Tighten the jam nuts to 60 Nm (44 ft. lbs.).
6. Inspect the toe angle to ensure proper adjustment and adjust as necessary.
Rear Toe Adjustment
Tools Required
^ KM-900 Rear Toe Adjusting Tool
^ S A9140E Torque Angle Gage
1. Remove the rear axle control arm bolts and cage nuts. Discard the bolts and nuts.
Important: Do not tighten the bolts at this time.
2. Install new bolts leaving the inside forward bolt out.
3. Install the KM-900 into the open bolt hole.
4. Using the KM-900, move the rear axle control arm in the direction of necessary toe correction.
5. Snug the rear axle control arm bolts.
6. Check the toe and adjust if necessary.
Notice: Refer to Fastener Notice in Service Precautions.
7. Using the SA9140E, tighten the rear axle control arm bolts.
Tighten the bolts and cage nuts to 90 Nm (66 ft. lbs.) plus an additional 30 to 45 degrees.
8. Repeat this procedure on the opposite side.