Rear caliper help (lockup) - 100S

Nitz Karl-GKN001
Tue, 23 Jul 2002 21:00:16 -0500

See below for the complete saga, however, in the end I did have to buy comp=
lete caliper carrier assemblies in order to fix the guide pin problem.  Luc=
kily, I found a source online for ~$38 each vs. the dealer's $105 each.

Everything went back together tonight, but I still ran into a problem after=
 I applied the emergency brake...they wouldn't release completely and the b=
rakes are dragging.  So I again appeal to those with more knowledge of how =
the calipers should operate to answer my question:

In playing with the emergency brake lever on the rear caliper, I have
some questions for those of you with more detailed knowledge of their
operation.  I was able to move the lever back to it's stop, and then I
cycled it back and forth a few times just to be sure the action was smooth.
However, it seems like the coil spring doesn't move the lever on it's own
(these test were done with the caliper off of the car).  Is this normal?
How does the e-brake release the pads in normal operation?  Is there enough=
 give in the system so that releasing the brake cable eases up on the pads,=
 or does the next regular application of the brakes help loosen things up?
I'm just trying to determine if my e-brake mechanism is OK, or if I'm going=
 to need rebuilt calipers, too?  The e-brake cables seems to move freely, t=
hough, so at least they're not broken or frozen.

After tonight's results, it seems like rebuilt calipers are likely needed. =
 I did soak the e-brake pivots in penetrating oil for a few days before rea=

Thanks for the help,
Karl in Johnsburg, IL
'92 Audi 100S, 125k miles
'81 VW Rabbit Diesel Truck, 201k miles

-----Original Message-----
From: Nitz Karl-GKN001
Sent: Monday, July 08, 2002 5:00 PM
To: '12V email list (E-mail)'
Subject: Another update - rear caliper lockup - 100S

Today's installment...

Foreign and other car parts sources locally said the pins were not availabl=
e to them.  The Audi dealer would only sell the pins as part of an assembly=
 with the caliper carrier ($110 each side).  The Audi part number for that =
kit is 443-615-425 B (was A).

Karl in Johnsburg, IL

-----Original Message-----
From: Nitz Karl-GKN001 []
Sent: Sunday, July 07, 2002 10:57 AM
To: '12V email list (E-mail)'
Subject: [V6-12v] Update - rear caliper lockup - 100S

So here's the latest...

First, thnaks to everyone who responded with suggestions.  The culprit on
the Driver's side was a frozen caliper in the applied position - hence the
smoke :-)  I bought the caliper guide pin seal rebuild kit, one for each
side, from the dealer for about $26 (included 2 rubber seals and grease for
the pins).  I cleaned the pins up (drill press and steel wool), lubed and
reinstalled with new pads.  All seemed well, so move on to the passenger

The passenger side rear caliper was frozen in the unapplied position (only
the pad on the brfake piston was doing any work).   The guide pins are
REALLY stuck in the carrier on this side, so I think I'm going to have to
replace the carrier.  The dealer was quoting $105 per side for that (and if
I do one side, I'll probably do both).

Thanks again,

-----Original Message-----
From: Nitz Karl-GKN001
Sent: Wednesday, July 03, 2002 8:59 AM
To: 12V email list (E-mail)
Subject: LR caliper lockup - 100S

Or the subject could read, "a funny thing happened to me on the way in the
office this morning..."

About halfway into work on my 35mile commute, I stop in traffic with the
windows down, and notice a cloud of brake smoke drift past my window.  After
seeing this for the second time, I pulled into the nearest parking lot to
investigate.  The Driver's Side (US car) rear brake pads were smoking.  Now
I know I drove a little spirited this morning, both nothing extreme enough
to smoke the brakes (let alone just on 1 corner).

This was my first time driving the car after returning from vacation (it's
been sitting about 3.5wks), but I've never had this problem before.  The
brakes were pressure bled last year.  The problem didn't seem much worse for
the rest of the drive in, and although hot, the pads were not smoking once I
got to the office.

My initial impression is that I will pressure bleed the brakes/clutch this
weekend again, and remove the rear wheel and see how bad the damage is to
the pads.

Has anyone out there found something more sinister to be the culprit for the
symptoms I described?  I know that the e-brake cables are either stretched
or just in need of adjustment, too.  BTW, any suggestions on a quick process
for accomplishing that.  The Bentley instruction seemed vague when I last
remember looking at them.

Thanks for the suggestions,
Karl in Johnsburg, IL