Wheel Alignment Measurement
Measuring Wheel Alignment
Steering 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/pull is defined as follows: At a constant highway speed on a typical straight road, lead/pull is the amount of effort required at the steering wheel to maintain the vehicle's straight path. Lead is the vehicle deviation from a straight path on a level road without pressure on the steering wheel. Refer to Radial Tire Lead/Pull Correction, in order to determine if the vehicle has a tire lead problem.
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. Refer to Fastener Tightening Specifications.
* 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. Refer to Wheel Alignment 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. Jounce 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. Refer to Wheel Alignment Specifications.
Front Caster Adjustment
Use the following procedure in order to prepare the top strut mounting holes:
1. Remove the top 3 fasteners from the strut tower.
2. Lift the front of the vehicle by the body in order to separate the strut from the inner wheelhouse. Refer to Vehicle Lifting.
3. Pop out the 2 guide pins.
4. Hand file the excess metal in order to make slotted holes.
5. Paint the exposed metal using rust preventative paint or primer.
6. Lower the front of the vehicle.
7. Install the strut attaching fasteners.
Do not tighten the fasteners at this time.
Notice: Refer to Fastener Notice in Service Precautions.
8. Move the top of the strut forward or rearward in order to adjust the caster. A 1 mm (0.040 in) position change at the tower is about equal to a 0.1 degree change in the caster. Refer to Wheel Alignment Specifications.
Tighten the strut fasteners to 47 N.m (35 lb ft).
9. Perform a complete wheel alignment.
Front Camber Adjustment
Tools Required
J 39601 Camber Adjustment Tool
1. Raise and support the vehicle. Refer to Vehicle Lifting.
2. Remove the tire and wheel.
Important: Do not allow the bolts to turn. This will ruin the serrated shoulder.
3. Remove the nut and tap the upper and lower bolt from the strut and knuckle.
4. Separate the strut from the knuckle.
Important: It is necessary to grind the lower bolt hole on the strut to achieve proper camber setting.
If camber specification is not achieved by this procedure check for bent or worn parts.
5. Using a round file or a die grinder file the inner metal plate to the outside plates diameter.
6. File excess metal to make the slotted holes.
7. Paint the exposed metal with rust preventive paint or primer.
8. Replace the strut to the knuckle.
9. Install both the upper and lower bolts.
10. Do not tighten at this time (leave loose).
11. Install the J 39601 to the bottom strut bolt.
Notice: Refer to Fastener Notice in Service Precautions.
12. Using the J 39601, set the camber. Refer to Wheel Alignment Specifications.
Tighten the upper strut to knuckle nut to 147 N.m (108 lb ft).
13. Remove the J 39601.
Tighten the lower strut to knuckle nut to 147 N.m (108 lb ft).
14. Replace the tire and wheel.
15. Lower the vehicle.
16. Perform a wheel alignment.
Front Toe Adjustment
1. Loosen the lock nuts on the tie rod.
Notice: Refer to Fastener Notice in Service Precautions.
Notice: Care must be taken that the boots are not twisted when rotating the inner tie rods, or damage to the boots may result.
2. Rotate the inner tie rod to adjust the toe. Refer to Wheel Alignment Specifications.
Tighten the lock nuts to 64 N.m (47 lb ft).
3. Adjust the boots as needed in order to prevent damage.
Rear Toe Adjustment
Important: Complete the left and right rear toe adjustments separately, per wheel. Use the following procedure.
1. Loosen the inner adjustment link cam nut.
Notice: Refer to Fastener Notice in Service Precautions.
2. In order to adjust the toe, rotate the cam bolt. Refer to Fastener Tightening Specifications.
Tighten the cam nut (2) to 91 N.m (67 lb ft).
3. Recheck the toe setting after tightening.
4. Readjust the toe setting if necessary. Refer to Wheel Alignment Specifications.