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 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 in order to determine if the vehicle has a tire lead problem.

Before making any adjustment affecting wheel alignment, perform the following inspections and adjustments in order to ensure correct alignment readings:

• Inspect the tires for the following conditions. Refer to the tire placard on the drivers door lock pillar.
  • Pressure
  • Size
  • Brand
  • Construction
  • Balance
• Inspect the tires for wear. Refer to TIRE DIAGNOSIS - IRREGULAR OR PREMATURE WEAR  in Tires and Wheels.
• Inspect the runout of the tires and the wheels. Refer to TIRE & WHEEL RUNOUT SPECIFICATIONS in Vibration Diagnosis and Correction.
• Inspect the wheel bearings for runout. Refer to HUB/AXLE FLANGE & WHEEL STUD RUNOUT INSPECTION in Vibration Diagnosis and Correction.
• Inspect the wheel bearings for looseness. Refer to WHEEL BEARINGS DIAGNOSIS  in Suspension General Diagnosis.
• Inspect the following components for looseness or wear:
  • The front knuckles
  • The control arm ball studs
  • The control arm bushings
  • The outer tie rods
  • The inner tie rods
  • The steering gear
  • The stabilizer shaft
  • The strut assemblies
  • The upper strut mounts
• Inspect the struts for leaks.
• Inspect the vehicle trim height. Refer to TRIM HEIGHT INSPECTION PROCEDURE  in Suspension General Diagnosis.
• Inspect the remaining suspension and steering components for damage. Replace all damaged parts prior to adjusting wheel alignment.
• Inspect the fuel level. 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 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 alignment angles:

1. Install the alignment equipment according to the manufacturer's instructions.
2. Perform the following procedure to normalize the suspension prior to measuring the angles:
   1. 2.1. Bounce the front bumper lightly three times.
   2. 2.2. Bounce the rear bumper lightly three times.
3. Measure the alignment angles.
4. Record the readings.
5. Adjust the front toe, if necessary. Refer to FRONT TOE ADJUSTMENT   .