Bearings (also called "cones") must be removed and cleaned before they can be inspected.
- After the bearings are cleaned, inspect them for damage.
- If a bearing is damaged, thes cause should be determine so the problem does not happen again.
- Check the bearing and bearing race for pitting and other signs of damage.
- Check the race for cracks due to improper fit, cocking or poor bearing seals.
- If any damage is apparent, replace the bearing and its race. Also correct bearing seats.
- Save the old bearing to compare it with the new one.
- Bearings usually fail slowly.
- Noise is the clue that something is wrong.
- If a possible wheel bearing groan is heard, driving the car can sometimes help pinpoint the problem.
- First, check the tires for damage and be sure they are properly inflated. Find an empty parking lot or deserted road and make slow left and right turns.
- This shifts the weight of the vehicle from one side to the other.
- When the weight is increased on the bearing, the noise increases. The inside tire always turns at a lower rpm than the outside tire.
- The noise from a wheel bearing that is bad will change pitch as the wheel speeds up and slows down when turning from one side to the other.
- When the outside wheel has the bad bearing, the noise will become worse because that wheel is turning faster.
- Applying the brakes can also cause the noise level from a bad bearing to become less as they contact the drum or rotor with the bad bearing.
- Spinning the wheels can be done using an on-the-car wheel balancer for non-drive wheels.
- As metal is deformed or comes off the bearing races, the noise will become more pronounced.
- There are two main kinds of damage to a bearing, spalling and brinelling.
- Spalling is when pieces break off of the bearing metal. The noise from spalling is a random, high-pitched sound.
A spalled bearing race. Courtesy of Chicago Rawhide.
- Brinelling is when the bearing or race has indentations from shock loads. The noise that results from brinelling damage is a regular, low-pitched sound.
Dents in the bearing race, called brinelling, result from the roller hammering against the race. Courtesy of Chicago Rawhide.