Groaning Brakes

[Paul Meyers]

Likely, the previous owner (I'm assuming there was one) replaced the
axle shaft with the wrong one. I was supplied with what looked like a
nifty rebuilt shaft, but, when I installed it, it would act just as you
described. It had only half the correct number of ABS teeth. The ABS
works by comparing the waveforms presented by the rotating teeth on
either side of the car. If it finds a difference, it modulates the
brakes to bring them to within tolerance. Since at slow speeds the
waveforms were always out of tolerance, the car would groan at each stop
just before coming to a stop. The problem went away when I installed the
correct shaft with the right number of teeth.
Paul Meyers

-----Original Message-----
From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com] On
Behalf Of Dr. Ian McArthur
Sent: Monday, January 27, 2003 11:21 AM
To: quattro at audifans.com
Subject: Groaning Brakes

This is a multi-part message in MIME format.
--
[ Picked text/plain from multipart/alternative ]
My 88 5TQ has a groaning brake.  Just as I stop the left front brake
groans
like it is about to chew itself to pieces.  This does not happen when I
turn
off the ABS.

I have changed everything but the axle shaft (rotor, caliper, pads,
wheel
bearing, bushes etc.).

Anyone have a suggestion?
************************************************
Dr. Ian McArthur, Consulting by Acronym, Cochrane, Alberta
3 5TQs
sutul at telusplanet.net
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