Parking Brake not releasing '89 100Q

[Fred Munro]

Hi Ben;

I found the rear brakes on the 5K and 200 to be a bit of a maintenance
problem.
There are three main causes for your slow e-brake release:
1. Sticky e-brake cables.
2. Corroded e-brake cam shaft
3. Seized caliper guide pins.

It is likely you have a combination of two or three.

The cable housing breaks at the moulded rubber attachment block near the
outer end. Moisture gets inside the housing and the cable gets sticky and
eventually seizes. To check the cable, remove it from the caliper and
push/pull it. It should move easily in the housing. If it doesn't, replace
it.

Now that you have the cable off, check the actuating cam. Pry it with a
screwdriver to activate the e-brake. When you release it, it should return
to the stop. It is very likely it will not. Return it manually to the stop
and remove the return spring. Using a screwdriver, you can pop the cam and
shaft up 1/2". Clean up and polish the shaft with a fine abrasive of your
choice. Don't damage the seal. Lube copiously with a water-proof lubricant
(I use FluidFilm, but I think it's only available in Canada). When free and
well lubed, the cam will return to the stop without the return spring
installed. Re-install the return spring - remember to use Loctite on the
bolt. Note here that if you enthusiastically move the cam back and forth
instead of up and down to work in the lube, you will lock your rear brakes
tight due to the adjusting action of the e-brake mechanism. Don't panic -
pound off the caliper and screw the brake piston back into the caliper. Try
to avoid this little scenario.

The caliper guide pins are almost guaranteed to be corroded if you drive in
the salt belt. Remove the caliper and pull the pins. Clean the pins and the
bores in the caliper carrier. If the pin boots are worn or torn, buy a
replacement boot kit. Throw away the lube that comes in the kit and lube
with a heavy synthetic "rubber friendly" grease. I use Superlube. The kit
also contains new self-locking bolts. The Bentley recommends that these
bolts not be reused and always be replaced.

There you have it. Once all this is done, you have a 90% chance that your
problem is fixed. If it isn't, the calipers are internally corroded and need
to be rebuilt. I've never had to rebuild a rear caliper, even after 300k km
of "super salt belt" driving.

The good news is that you get to do it all again next year if you want to
keep the rear calipers in good working order :o)

Thankfully, the UrS4 rear calipers seem to be standing up better than the
5k/200 calipers did. The rear brakes even work hard enough to keep the
rotors shiny!

HTH

Fred Munro
'94 S4  118k km

----- Original Message -----
From: "Swann, Benjamin R. (BSWANN)" <BSWANN at arinc.com>
To: <quattro at audifans.com>
Sent: Thursday, December 21, 2000 11:16 PM
Subject: Parking Brake not releasing '89 100Q


> I apologize for not getting back with other listers regarding other posts
> about cams, etc.  My daughter has been in the hospital recovering from
some
> rather nasties, and this has consumed all of my time.
>
> I was hoping listers might give me some insight about the parking brake
> calipers not releasing on the 100Q.  I found this out when I took it
through
> inspection for the new owner, thinking I'd addressed all of the issues -
> well I was close, but this one got me.
>
> Symptoms, not obvious to me, but the inspector caught it, are the brakes
do
> not release right away after letting off the brake lever.  It seems the
> problem may be worse now in the clod weather, as I notice drag whereas
> didn't before inspection.
>
> I have a new set of pads and rotors, but didn't put them  on the car as
they
> were OK.  The inspector said they were marginal but passed them.  I wonder
> if I replace the pads and rotors and lubricate everything well will
resolve
> the problem.  Or am I wasting my time and need to get some new/used good
> calipers.
>
> I appreciate the replies which I won't be able to read right away, but
will
> get me on the right track as I attack the problem over the Holidays.
>
> Merry  Christmas and Happy Holidays to all.
>
> Ben