Measuring Wheel Alignment

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 Wheels, Tires and Alignment 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 for worn wheel bearings. Replace if necessary, refer to Wheel Bearing/Hub Replacement - Front in Suspension.
- Inspect the control arm ball joints and the tie rod ends. If they are loose, tighten them before adjusting the wheel alignment. Refer to Fastener Tightening Specifications in Power Steering System or Fastener Tightening Specifications in Suspension.
- Inspect the run out of the wheels. Refer to Tire and Wheel Run out Specifications in Vibration Diagnosis and Correction under Steering and Suspension Testing and Inspection.
- 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 .
- Inspect that the steering gear is not loose at the frame. Refer to Power Steering Gear Replacement (Automatic Transmission) or Power Steering Gear Replacement (Manual Transmission) in Power Steering System.
- Inspect the lower control arms for looseness. Refer to Lower Control Arm Replacement in Suspension.
- Inspect the stabilizer shafts for loose or missing parts. Refer to Stabilizer Shaft Replacement in Suspension.
- Inspect for worn struts. Refer to Strut Assembly Replacement in Suspension.
- 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:
1. Install the alignment equipment according to the manufacturer's instructions.
2. Jounce the front bumpers lightly three times and jounce the rear bumpers lightly three times to normalize the suspensor prior to measuring the angles.
3. Measure the alignment angles.
4. Record the readings. If adjustments are required, make them in the following order:
4.1 Adjust the caster.
4.2. Adjust the camber.
4.3. Adjust the toe-in.