Wheel Bearings Diagnosis (Tapered): Etching

Fig 1: Identifying Etching

Courtesy of GENERAL MOTORS CORP.

The bearing surfaces appear gray or grayish black in color, with related etching away of material usually at roller spacing.

1. Check the seals.
2. Check for proper lubrication.
3. Clean all of the parts and the housings.
4. Replace the bearings. Refer to WHEEL HUB, BEARING, AND SEAL REPLACEMENT in Front Suspension.