How to find bad wheel bearing?

[Doyt W. Echelberger]

The method described is not perfect and will result in occasional mistakes.
The longer you allow the failing bearing to remain in place, the worse it
usually gets and the stronger the clues become, so I think there is some
advantage to not fixing it right away. And also consider that you may be
dealing with more than a single bearing failure. Frequently they go in pairs.

The bearings that went bad on my cars (4kq and 5ktq) gave rumbling sounds
that could be felt through the steering wheel while driving, and the
rumbling became louder when the bearing was loaded by a turn. Doing figure
8's in a parking lot was useful to establish the problem as one of a
failing wheel bearing. But this did not point to any specific wheel.

Stage two was performed on a lift that allowed the wheels to dangle,
unsupported. In this position, the car was started and put into gear and
allowed to run at a steady speed. Each wheel hub was examined in two ways:
The hub was touched and felt for vibration and compared to the other
wheels, and a stethoscope was applied to each hub and the grinding sounds
were compared. The fact that the bearings were not loaded by the full
weight of the car is a flaw in the above method. But we never found any way
to touch and listen with the 'scope without using the lift. And there is a
safety risk of getting tangled up in rotating shafts and wheels.

In one case, the method indicated a left front bearing failure, and after
the repair the rumbling under load remained, although the removed bearing
did show erosion of a race. We did the right front hub and found an even
worse erosion, and after replacing both front wheel bearings the rumbling
was gone.

The only certain method is to make a decision based on touch and sound, and
pull the bearing and examine it. Test the car after the repair, and if the
rumbling is gone, you fixed it. If a rumbling remains, replace the next
most likely bearing and test the result. Continue this process until the
rumblings have stopped or until your wallet and credit is exhausted. I am
very open minded to a better method.

Doyt Echelberger


 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
At 11:55 AM 5/12/2002 +0200, you wrote:
>How can I find out what wheel bearing is bad? At first it sounded like
>the right rear, then left front, now I'm not really sure. At least it
>is pretty noisy now...
>
>--
>E. Spangen
>'90 Audi 200TQ 20v (godt parkert i låven uten skilter)
>'96 Sykkel, drevet av '81 fattig student