[Vwdiesel] Continuing brake Problems

[Chris Boyer]

Hi, Kerry....if you're bleeding the brakes and every time you get air, that
means
there is air leaking into the system.  Unless your proportioning valve has a
leak, I doubt it's defective.

Before you spend your money on a proportioning valve, replace that rear wheel
cylinder which bubbles upon bleeding, and give it another shot.   I think I
spent
about $6-$12 for a wheel cylinder last time I bought one.

If your mechanic is sure it's the proportioning valve, let him buy it and
put it in.
Pay him if it works.  Ask him to explain how a bad proportioning valve causes
air bubbles in the fluid.  Please send me his response; I'd love to know.

If you're damned sold on replacing the proportioning valve, and don't want to
spend the money for a factory unit, get one from Wilwood.  You'll need to
adjust
it, but you can manually adjust the pressure differential between the front
and rear
brakes.  Make sure the proportioning valve you are replacing doesn't have a
delay valve built in.  The delay valve keeps the front brakes from applying
until
the rears have about 150psi line pressure.  The 150psi gives the rear
brakes a chance
to overcome return spring pressure so they apply at the same time as the
front brakes,
which do not have return spring pressure to overcome.


Let me know what you find if you get a chance.  I think you're overlooking
something
really simple, but deceptive.  You'll get it.

Regards,

Chris Boyer


At 07:13 PM 1/6/03 -0500, crusader wrote:
>After much frustration, I broke down and took to car to my local mechanic
>who also believes that it is the proportioning valve.  He also added that it
>is pricey.
>
>Does anyone know of a used one for sale?
>
>Thanks,
>
>Kerry
>----- Original Message -----
>From: "Chris Boyer" <boyer at cts.com>
>To: "Nate Wall" <nwall at opei.org>; "crusader" <crusader at nccw.net>
>Cc: <vwdiesel at audifans.com>
>Sent: Monday, December 30, 2002 2:11 PM
>Subject: Re: [Vwdiesel] Continuing brake Problems
>
>
> > I had a bad rear wheel cylinder on an A1 and it just wouldn't bleed.  It
> > didn't leak
> > in the pressure mode, but it sucked in air when it retracted.  I bled the
> > damn thing
> > for hours until I talked to a buddy who suggested replacing it.  Cured it.
> >
> > Regards,
> >
> > Chris Boyer
> > San Diego
> >
> > At 10:59 AM 12/30/02 -0500, Nate Wall wrote:
> > >What type of VW? The A-2 Jettas have a load-sensing proportioning valve
> > >next to the rear axle beam that sometimes leaks fluid.
> > >
> > >--Nate
> > >
> > >crusader wrote:
> > >
> > > > This is a multi-part message in MIME format.
> > > > --
> > > > [ Picked text/plain from multipart/alternative ]
> > > > Thanks to all of you who responded to my question last week about my
> > > failing master cylinder.  I replaced it and bled all 4 wheels.  However,
> > > on the rear driver side, the line bubbled and foamed no matter how much
>I
> > > bled.  After noticing that I had good "pedal" I gave up.
> > > >
> > > > Now, four days later, my pedal started to sink and after two more days
> > > I was back to pumping 3-4 times before I got any braking action.  The
> > > difference now, is that after I pump it up, the pedal does not sink as
>before.
> > > >
> > > > I just bled that back wheel again and I continue to get foaming fluid
> > > out of the wheel cylinder.  Can the wheel cylinder be the problem?
> > > >
> > > > Thanks again,
> > > >
> > > > Kerry
> > > > --
> > > >
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