Brake behavior

[Mark Rosenkrantz]

Sounds like air in the ABS pump, or (even more likely) a blown seal due to
pressure bleeding.  I'm not sure the procedure to bleed on the older cars.
On the newer cars, you use VAG-COM to operate the ABS pump while bleeding.

On older cars, I use a Vacula for bleeding.  Vacuum bleeding the system is a
bit safer on the seals than pressure bleeding brakes of clutches.

Mark

On Fri, Nov 20, 2009 at 9:22 AM, Grant Lenahan <glenahan at vfemail.net> wrote:

> this is mysterious, but i've observed other go through similar
> agony.  So at least consider and check:
>
> 1. did you bleed the ABS dry? If so you must cycle the ABS pump with
> the bleeder in place or it pumps air.
>
> 2. could you have gotten dirt in a caliper so it wont release?
>
> 3. could you have an ABS control module failure? I have no idea why
> bleeding would cause this, so its unlikely, but i did hear of it
> causing a very similar problem once
>
> Grant
> On Nov 19, 2009, at 9:47 PM, Brian K. Ullrich wrote:
>
> > Hi all.
> >
> >
> >
> > I'm a regular poster in the V8 and 200Q20v lists, but I have a
> > question that
> > is really related to a 1990 200tq 10v, and thought you guys could
> > help. A
> > little background first:
> >
> >
> >
> > I have replaced everything that is rubber under the car, including
> > shocks,
> > lower control arms, tie-rod ends. In doing so, we removed each wheel
> > assembly in the front including the calipers, as well as the
> > calipers in the
> > back. We did the brake lines and pads all around. Prior to doing
> > so, the
> > brake pedal was firm, but sort of dead, meaning that the power
> > assist did
> > not seem to be active. It felt like a conventional, non-powered brake
> > system. But, it worked. No ABS light, and the car stopped quite well.
> >
> >
> >
> >
> >
> > Once we re-assembled the car, we re-pressured the lines, and then
> > bled out
> > the brakes using the pressure system. They bled well (a TON of
> > fluid), but
> > when we put the car on the ground, the pedal pulsed, and then went
> > straight
> > to the floor, and the calipers seem to have clamped down. We can
> > still roll
> > the car, but clearly the brakes are not working.
> >
> >
> >
> > I am not familiar with this braking system, so I'm in the dark, and
> > my Audi
> > wrench is more familiar with B4+ cars, so this one is a mystery to
> > him as
> > well. His first thought is master cylinder (not leaking), or the
> > bomb (which
> > neither of us have much knowledge of, either than it exists).
> >
> >
> >
> > Does anyone have any words of wisdom here?
> >
> >
> >
> > Thanks!
> >
> >
> >
> > Brian
> >
> > _______________________________________________
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> > http://www.audifans.com/mailman/listinfo/quattro
> > http://www.audifans.com/kb/List_information
> >
>
>
>
> Grant Lenahan
> glenahan at vfemail.net
> (201) 602-4702 mobile
>
>
>
>
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