Wheel Bearing Maint. question

["Matt Rooke" <mrooke@fcpa.fujitsu.com>]

I am curious about the collective opinions regarding wheel bearing
maintenance.  Is it a good idea to clean and repack them, or even replace
them?  What grease should be used?  My CQ has 115k and I've never touched
them.

Background:  I have developed a light squeaking noise.  Sounds like it is
coming from bottom rear of car.  It only occurs between 40-50mph, it
"modulates" and the modulation frequency (but not that of the actual
squeak) varies with speed.  Sounds like about once per rev of the wheels.
Brakes (pedal and hand), acceleration, coasting- no effect.  It goes away
after a minute or 2, and doesn't return until the car has sat for some
number of hours.  After eliminating the brakes, seems wheel bearing is the
next likely suspect.  But none of the hubs get hot, so it is not very
bad... yet.

Given the elusiveness of this one, I don't expect to further isolate it
unless it gets a lot worse.  I wonder  whether it would be worth pulling
the bearings to inspect/ clean/ replace them.  It might not fix the
problem, but maybe it is good maintenance anyhow?  Has anyone else
experienced a bearing failure?  What are the symptoms?    Any other
suggestions for possible causes?
TIA,
Matt Rooke
San Jose CA
'91 CQ