Wheel Alignment Measurement

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. Determine if the vehicle has a tire lead problem. Radial Tire Lead/Pull Correction

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

• Inspect for visible damage to the suspension components and replace as necessary.
• Inspect the tires for the proper inflation. Vehicle Certification, Tire Placard, and Anti-Theft Label
• Inspect for irregular tire wear. Tire Diagnosis - Irregular or Premature Wear
• Inspect for runout of the wheels and the tires, correct any conditions as necessary.
  • Tire Diagnosis - Waddle Complaint
  • Wheel Mounting Surface Check
• Inspect the wheel bearings for backlash and excessive play. Wheel Bearings Diagnosis
• Inspect the ball joints for looseness or wear:
  • Lower Control Arm Ball Joint Inspection - Front
  • Lower Control Arm Ball Joint Inspection - Rear
  • Upper Control Arm Ball Joint Inspection - Front
  • Upper Control Arm Ball Joint Inspection - Rear
• Inspect the tie rods for looseness or wear.
  • Steering Linkage Inner Tie Rod Inspection
  • Steering Linkage Outer Tie Rod Inspection
• Inspect the control arms, stabilizer shaft and stabilizer links for looseness or wear.
• Inspect the steering gear for looseness at the frame. Fastener Specifications
• Inspect the struts/shock absorbers for wear, leaks, and any noticeable noises. Suspension Strut and Shock Absorber Testing - On Vehicle
• Inspect the vehicle trim height. Trim Height Inspection
• 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. Wheel Alignment Specifications 

Perform the following steps in order to measure the front and rear alignment angles:

1. Disable the rear steering and entry egress modes prior to starting the alignment.
2. Prior to starting the alignment procedure, you must do several parking lot steering maneuvers prior to driving up on the alignment rack.
3. Place the vehicle on an appropriate alignment rack.
4. Chock the wheels.
5. Place the vehicle in the neutral.
6. Place the vehicle in alignment mode. Alignment Mode Selection
7. Install the alignment equipment according to the manufacturer's instructions.
8. Jounce the front and the rear bumpers 3 times prior to checking the wheel alignment.
9. Measure the alignment angles and record the "before" readings and compare them to the specifications. Wheel Alignment Specifications 
10. Prior to making any front or rear caster and camber adjustments, you must return the vehicle to a hoist. DO NOT use the alignment rack to make any adjustments to camber and caster. Adjust the alignment angles to specification in the following order for a proper alignment:
    1. Adjust the rear camber. Rear Caster and Camber Adjustment 
    2. Adjust the rear toe. Rear Toe Adjustment 
    3. Adjust the front camber. Front Caster and Camber Adjustment 
    4. Adjust the front toe. Wheel Alignment - Steering Wheel Angle and/or Front Toe Adjustment 
11. Record the "after" readings.
12. Center the steering wheel angle sensor. Steering Wheel Position Sensor Centering
13. Place the vehicle in park.
14. Remove the wheel chocks.
15. Remove the alignment equipment.
16. Remove the vehicle from the alignment rack.
17. Enable rear steering and entry egress modes.
18. Deactivate Alignment mode using one of the following two methods:
    • Push the button on the center stack to turn off alignment mode.
    • Drive the vehicle over 16 km/h (10 MPH) to exit alignment mode.