RE: Brakes sticking, when hot

["Titus, Brian (NJAOST)" <BTitus@njaost.ml.com>]

I had this happen on my 885ksq, and I believe it just needed a new MC. Don't
have the shop records with me at the moment to verify; it was a local
mechanic, not an Audi dealer who fixed it. Brakes have been fine for 2
years.

> -----Original Message-----
> From:	Lino M. Valadas [SMTP:valadasl@osha.igs.net]
> Sent:	Wednesday, March 25, 1998 11:01 PM
> To:	jplewis@cats.ucsc.edu; quattro@coimbra.ans.net
> Subject:	Re: Brakes sticking, when hot
> 
> >My brakes stick on, only when driving in stop and go type traffic, and
> >or hot weather. Car is 86 5KTQ. just bled and replaced fluid. Seems to
> >pass servo test per Benltey.Could it be the check valve on the bomb?
> >Should I rebuild, replace the servo?
> >Any btdt's?
> >Any help would be appreciated. do not want to go to a mechanic. The list
> >has helped me more than any mechanic ever has!
> >
> >
> Don't know what it is.  I thought I had fixed mine, but today it came
> back.
> When it happened to my 86 5ktqw a couple of years ago, I went to my
> friendly
> Audi dealer, and they said: " Oh yeah, it happens only to some cars we
> don't
> know what causes it but the only way to fix it is to replace both the
> servo
> and the MC" (not the engine).  So I decided to diagnose it myself.  Went
> to
> the scrap yard and picked up a set from a 5ks, and did a swap with mine.
> Same problem.  So I put my MC back but kept the replacement servo.  Same
> problem.  At the point for some reason I felt the fault was with the
> servo,
> and kept replacing them.  3 servos later a found one that worked.  It
> worked
> fine for two years.  Today in stop-and-go traffic it happened again.
> Maybe
> it is the servo again.  But I'm starting to wonder if it might be related
> to
> the type of brake fluid I'm using or the age of it.  My bomb is new BTW.
> My
> next step is to flush the system with pentosin (brake fluid, not the stuff
> in the bomb) and see if that helps.
> I hope somebody else may be able to shed some light on this.
> 
> Lino
> 86 5ktqw