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 all the tires for proper inflation pressures. |
| • | Inspect that all tires are of the recommended size. |
| • | Inspect that all tires have about 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 runout of the wheels and tires. |
| • | 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 that the steering gear is not loose 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. |
Consideration must be given 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. Consideration should also be given to the condition of the equipment being used to adjust alignment. Be sure to follow the equipment manufacturer's instructions. Regardless of the equipment used to adjust alignment, the vehicle must be 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, the alignment angles should be corrected.
Perform the following steps to measure the wheel alignment angles:
| • | Install the alignment equipment according to the manufacturer's instructions. |
| • | Jounce the front bumpers lightly three times and jounce the rear bumpers lightly three times to normalize the suspension prior to measuring the angles. |
| • | Measure the alignment angles. |
| • | Record the readings. If adjustments are required, make them in the following order: rear camber, rear toe, front camber, and toe. |
