Re: Brakes sticking, when hot

["Lino M. Valadas" <valadasl@osha.igs.net>]

>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