GM Service Manual Online
For 1990-2009 cars only

Inspection Procedure

    Warning: Road test a vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.

  1. Road test the vehicle in order to verify the customers concern.
  2. Note: Sealed wheel bearings emit a howling sound when loose or damaged. Wheel bearing noise is present only when the vehicle is moving. The noise is constant and unwavering and increases with the speed of the vehicle.

  3. Verify the noise is from the wheel bearings. If the noise cannot be determined to be from the wheel bearings during the road test, raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  4. Inspect for bent wheels.
  5. Inspect for out-of-balance tires.
  6. Inspect for out-of-round tires.
  7. Spin the tire and wheel assemblies. Listen for wheel bearing noise.
  8. Note: The front wheel bearings are pressed into the knuckle. The rear wheel bearings are in the brake drum and wheel bearing assembly. If the inner race separates from the rear wheel bearings, noise results.

  9. Inspect for loose wheel bearings. If the front wheel bearings are loose, replace the front wheel bearings. Refer to Wheel Hub, Bearing, Knuckle, and Seal Replacement. If the rear wheel bearings are loose, replace the brake drum and wheel bearing assembly. Refer to Brake Drum Replacement.
  10. Lower the vehicle.