Re: Rear brake caliper siezing or dragging?

[Igor Kessel <e6941tb@ix.netcom.com>]

Colin Barfoot wrote:
> 
> Qlisters please assist I need to know by tommorrow AM if possible to order the
> correct parts...
> I just had my new rebuilt calipers put on Wednesday and then the car was taken
> for a test drive after the first application or so the right rear caliper was
> siezed on again! ( actually the mechanic said he could only just feel it
> againt my powerful engine...(thanks SK(R)) This was the same one which had
> failed before???!!

Check the jacket on that side's emergency cable. Audis like to wear them through, 
after which they rust inside and one day fail to release the pads. That's exactly 
what I had several years ago.

I have an underground garage in my house. The driveway is fairly steep
and that requires the cars to be parked with both Reverse engaged and
the e-brake pulled up to the last click (my Q was caught twice with it's
nose up against the garage door, to which it had creeped in Reverse when
the e-brake was not completely up).

In the winter, before a snowstorm I always leave the Q outside and the
Fox in the garage (obvious reasons).
One subzero morning 2 years ago I took my 3 buddies for a ride (the
purpose - to brag about what a chipped 200 turbo quattro can do in
snow). At the time one of them owned a VR6 Passat, another one - a
K-bodied Primus (absolutly the worst  car that I've ever driven) and the
third one - nothing yet. (BTW, the first one now owns an A4Q, the second
one - a chipped GolfIII and the third an AWD Colt (Mitsu) and a chipped
GolfIII. Speaking of power of propaganda! Didn't I deserve a price break on my new
A4TQ, AoA?).

So, we've been merrily traveling at about 3 times the speed of traffic,
when one of my friends asked me to yeild the place behind the wheel. We pulled
over and got out of the car. At this point we've noticed white smoke,
coming from the LT RR wheel and boy, did it stink! The brakes were
seized.
It turned out that when I released the lever while leaving the driveway,
the e-brake did not disengage. The jacket on the cable was worn through
and the water, which penetrated it, froze solid. The funniest thing was,
the car was so powerfull that I did not notice a dragging wheel even
with three passengers!

> My understanding is (correct if wrong) :The pistons can normally just be
> depressed enough to put in the pads on, to depress further requires screwing
> in the piston.

Well, mine wouldn't even move in without a special tool, that I made for this 
purpose, compressed with a C-clamp, while being screwed in.

>  The mechanic said that on the caliper which siezed on he could depress the
> piston manually all the way.  Also with the system pressurized he could still
> depress the one caliper (the one siezed on) but the other one (which worked
> fine) could not be depressed.

Sounds like the caliper is history.

> I sent the siezed on caliper back to the supplier and it will be replaced with
> a different one, but I'm wondering (due to the recent thread on the RR caliper
> dragging with a stuck MC if thats what I have too.  I'll try at least to order
> a new MC tommorrow.

Naah, you'd be dragging both RR wheels (I had this too).

> On the MC does anyone know if you can just order the larger one from the
> wagon(or a later Quattro?) will it fit/work ok?
> Opinions?

This past winter, when I had the same problem, I've done some recearch (it's a 
repost):
The MC was $200 from my local parts go-getter ($470 from a dealer -
ouch!). Jim @ Blau suggested a 5000 unit for $98 which according to him
would've fit. Without questioning Jim's competence (he knows Audis
pretty well), but given a substantial price differential, I've asked
myself a question: where's the catch? Oh, well, back to my collection of
microfiches for all 44 bodied Audis. All 200 owners please take note of
the following:

A 10v 200 will take 3(!) different MC's (and 2 different hydroboosters):

1. VIN up to 44_K_010 000: 447 611 021 (25,40x18/18)
2. VIN up from 44_K_010 001 on: 441 611 021A (25,40x17.5/18)
2a. also use: 853 612 129

A 5000 will take 2 different MC's:

3. 443 611 021 (23,81x19/17)
4. 447 611 021 (25,40x18/18) for vehicles w/larger permissible load (and
wagons).

Please note that §1=§4. Which means that a 5000 unit would probably fit,
but hey, we have a 200 with a larger (25mm vs. 23mm dia.) bore in the MC
for the improved braking ability. To me it was definetly worth extra
$100 and I ordered the original one.

HTH
-- 
Igor Kessel
'89 200TQ - 18psi (TAP)
'97 A4TQ - on the dealer's lot
Philadelphia, PA
USA