[s-cars] Urgent - Caliper retraction

[Paul Heneghan]

Hello Aaron - you need the Bentley manual - it describes the procedure:
Section 46-29:
Installing
- Press piston in by turning clockwise and pushing forcefully.

Just did mine today.  I was trying to free up the hand brake mech, and
forgot that it keeps ratcheting the piston out.

You can't push the piston back - because of the self-adjusting handbrake
mech, you have to screw it back in - that's why it's got two v-shaped
grooves on the front face.  I didn't have the correct tool (I have the old
hex tool that older Audis used to use), so I used a pair of vice grips to
grip the piston (without tearing the rubber boot) and rotated it back in -
it wasn't difficult - for the last 5mm or so, i was able to turn it with my
fingers.

After I'd reassembled everything, I discovered I had a working handbrake
(hurray!), but a spongy brake pedal (boo!) - obviously while working the
handbrake mech, I'd pushed the piston out a tiny bit too far and let some
air in.  I need to bleed the brakes anyway - it's been about three years
since the entire system was bled, and the water in the fluid will rust up
the pistons if it's not changed regularly.

Incidentally, one of the slider pins had seized completely - freed with
judicious use of penetrating oil, a hammer, a spanner, a file, some 240grit
wet&dry, and some grease.  The pads were binding in their housing due to
rust - fixed by removing the carrier and filing down the surfaces that the
pads slide on and also filing down the rust build-up on the pads' backing
plates.   The handbrake mech had seized - fixed by removing the end stop
bolt, lifting the lever out of the calliper body by about 8mm, and wrapping
a strip of 240grit wet&dry around the shaft to remove the build-up of rust.
A few drops of penetrating oil later, and the handbrake mech is now
returning to the rest position again.  A typical Saturday afternoon in the
life of an Audi owner.  I wonder how much the dealer would have charged to
remedy the problem - got to be high ???s.

Paul

-----Original Message-----
Message: 7
Date: Sat, 22 Oct 2005 15:26:11 -0500
From: <aaront at cox-internet.com>
Subject: [s-cars] Urgent - Caliper retraction
To: s-car-list at audifans.com
Message-ID: <20051022202611.TGZ6826.fe1 at localhost>
Content-Type: text/plain; charset=ISO8859_1

Hi all,
Im in the middle or a rear brake job.
Any tricks to getting the rear claiper to retract?  Im ready to reinstall
but cant retract.
I actuated the Ebrake linkage with the caliper off and the puck wont go
back.
Any other  things to do besides cleaning and lubing the slider pins?
Thanks
Aaron