[Biturbos4] Shuddering brakes (StopTech) EZ fix - long

Single Malt s_malt at yahoo.com
Sun May 29 13:56:53 EDT 2005

I thought I'd share a recent repair I performed on my
car.  For many of you this will be unworthy of the
time it takes to read, but perhaps some will find this

After a recent track event, my brakes developed a
shudder that was not too severe, but needed attention.
 A fellow Audi club member was kind enough to offer
some guidance on a resolution path that would be quite
simple ... Being a little wary of DIY'ing things as
important as brakes, I bribed him with dinner and he
came over to help out.

Among the possibilities of what was causing the
shudder ranging from pad deposits on the rotors to
warped rotors (which is apparently fairly rare) was
his suspicion that the pads were damaged or uneven
from a poor bedding in process early in the pads life.
 Armed with new pads (in the event that the existing
pads were indeed shot), we dug in.  Our objective was
to inspect the brake pads and, if needed, sand them
flat again.  A test drive would determine if the
shudder's cause was something else.  The rotors would
be visually checked at the same time.

Please forgive my ignorance of the correct semantics
as I describe the process.

Tools: jack, 17mm socket (for wheel removal), torque
wrench for 90ft/lb torque when replacing wheel, 6mm
allen wrench, rubber mallet or hammer and wood block,
screwdriver, sandpaper.

Working from one side at a time, we removed the wheel
and turned the steering to expose the caliper for ease
of access.  The StopTech caliper has an I-shaped
retaining piece that is fairly easily removed by
removing the two long allen-headed bolts from top and
bottom.  A little screwdriver prying and this retainer
pops out (along with a rounded rectangle that acts to
secure the pads in position).  Grasping the ears of
the pad with a channel lock pliers, I could wiggle and
pull until the pad was extracted through the access
point opened by removing the I-shaped retainer.  The
pad looked OK, but did have evidence of slightly
uneven wear.  Laying my 80-grit sandpaper on the
garage floor, I lightly ran the pad over the paper
several times.  The sanding action revealed the truth
of it's uneven surface.  The leading and trailing
edges of the pads were feathered or rounded off. 
After sanding until the entire pad was evened out, I
replaced that pad and extracted the next.  Same wear
was evident so I repeated the process.  The pads were
in otherwise fine shape.  With the StopTech's, it was
necessary to be cautious that the rotor stayed in
place as it would easily shift out of position with
the pads missing.  Because I was not replacing the
pads, pushing the brake pistons back in was not
needed, however the pads did need a little tapping to
get them back into place.  Replacing the I-shaped
retainer required a little tapping with a hammer and
wooden block to get it seated enough to replace the
allen-headed bolts.

The test drive proved our efforts were successful, the
grilled burgers were good and the beer was cold ... a
good night overall!

Repair time ... maybe 45 minutes, but it was a
learning session so next time I expect maybe 20 (and
that includes jacking up the car and removing the
wheels).  While certainly not a "mechanic" per se,
I've done a number of maintenance and repair
procedures (spark plugs, oil changes, filters) to my
car and have a background that includes some minor
mechanical work ... IMO, this job was easy.  I think
replacing the cabin filter took more time!

The last time I had this shudder (after a track event
then too), it was with stock brakes and the rotors
(while not warped) were in need of replacement ...
hence an opportunity for the StopTech's.  This
procedure was significantly cheaper! :)

Disclaimer:  This is not meant to be a How-To.  It is
a diary of what I did.  I am an untrained moron.  If
you follow this procedure yourself, I cannot be held
responsible for any property damage or personal

Single Malt
'01.5 S4
Garaged at 9200ft
just outside Denver, CO

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