Steering and vibration complaints are not always the result
of improper alignment. 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. Refer to
Radial Tire Lead/Pull Correction
in Tires and Wheels
to determine if the vehicle has a tire lead problem. Before making any adjustment
affecting wheel alignment, make the following inspections to ensure correct
alignment readings and adjustments:
| • | Inspect the tires for proper inflation pressures. |
| • | Inspect the tires for recommended size. |
| • | Verify that all tires have the same tread wear. |
| • | Inspect the wheel bearings for proper adjustment. Correct if necessary. |
| • | Inspect the control arm ball stud, inspect the relay rod and inspect
the tie rod ends. If they are loose, correct them before adjusting the wheel
alignment. |
| • | Inspect the vehicle trim height. If the vehicle trim height is
out of limits, make the necessary corrections before adjusting the wheel alignment.
Refer to
Trim Height Specifications
in Suspension General Diagnosis. |
| • | Inspect the steering gear for looseness at the frame. |
| • | Inspect the lower control arms for loose bushings. |
| • | Inspect the stabilizer shafts for loose or missing parts. |
| • | Inspect for leaking or worn out struts. |
| • | Inspect for leaking or worn out shock absorbers. |
| • | Inspect for worn or loose strut upper mounts. |
| • | Inspect the remaining suspension and steering components for damage.
All worn parts must be replaced prior to adjusting the wheel alignment. |
| • | Inspect the vehicle for stability. The fuel tank should be full
or the vehicle should have compensating ballast. |
Give consideration to excess loads, such as tool boxes, sample cases,
etc. If these items are normally carried in the vehicle, they should remain
in the vehicle during alignment adjustments. Consider also the condition of
the equipment being used in order to adjust the alignment. Follow the equipment
manufacturer's instructions. Regardless of the equipment used to adjust the
alignment, keep the vehicle on a level surface, both front-to-rear and side-to-side.
Satisfactory vehicle operation may occur over a wide range
of alignment settings. However, should the settings vary beyond the specifications,
correct the alignment angles.
Perform the following steps in order to measure the wheel alignment
angles:
| • | Install the alignment equipment according to the manufacturer's
instructions. |
| • | Prior to measuring the angles, jounce the front bumpers lightly
3 times and jounce the rear bumpers lightly 3 times in order
to normalize the suspension. |
| • | Measure the alignment angles. |
| • | Record the readings. If adjustments are required, make them in
the following order: |
