[s-cars] Brake Fluid Equalizer

[Paul Heneghan]

Rear brakes failing - very common on Audis.  Happened on all four of mine.

A number of things:

Proportioning valves seize up from rust and also from not being used enough
(car would need to be regularly loaded to capacity and emptied).  I did
manage to free up one of mine by spraying it with penetrating fluid and
exercising it vigorously.

Hand brake cables go rusty and seize up.  This in turn causes the parking
brake mechanism inside the rear callipers to seize up (although they can
seize up on their own as well).

Seals on sliding pins on rear callipers fail leading to water ingress, rust
and seizure (although this can happen even with the seals intact).  This can
be diagnosed by clear signs of one surface of the disk not being used.

Pads rust themselves to carriers - this prevents them moving freely - again,
extreme cases can lead to the calliper not auto centring properly.

Have a look at: http://www.eveshamsquash.co.uk/audi/parkingbrake.html

A bit out of date, but still mostly true.

Paul

-----Original Message-----
Message: 7
Date: Mon, 18 Jun 2007 17:04:00 -0400
From: "Max Hoepli" <mhoepli at vif.com>
Subject: [s-cars] Brake Fluid Equalizer
>
> The rotors in the back were rough, rusty on the inner surfaces. only the
outer surfaces were touched by disc pads.