quattro digest, Vol 1 #4573 - Failre-brake prop valve vs MC

[Larry C Leung]

> From: "Alexander, Tyson" <TRAlexander at PatioEnclosuresInc.com>
> To: "'quattro at audifans.com'" <quattro at audifans.com>
> Subject: Failure-brake proportioning valve vs.master cylinder
> Date: Wed, 5 Feb 2003 12:02:16 -0500
>
> Oh Great and Powerful List,
>
> The short question:
> 86 4kcsq- 180k miles- Which is more likely to go first, the brake
> proportioning valve or the master cylinder.


No direct experience with a 4KQ, but my A2 GTi's proportioning valve
failed while the MC was fine. The symptom for mine was a stiff pedal
when the valve failed in the front biased position. When adjusted to a
heavily rear biased position, the pedal gets softer. So, it is possible
for you (if the proportioning lever can be moved, another way of
diagnosis),
to see if this will help your diagnosis. As for my GTi, when the valve
failed, the lever was essentially, seized. The spring allowed the
suspension
to move.

LL - NY