Date:         Tue, 31 Jul 2001 16:25:20 -0700
Reply-To:     "Moritz, Thomas W NWW" <Thomas.W.Moritz@NWW01.USACE.ARMY.MIL>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         "Moritz, Thomas W NWW" <Thomas.W.Moritz@NWW01.USACE.ARMY.MIL>
Subject:      Brake problem
Content-Type: multipart/alternative;

Our mechanic is getting frustrated - more so because I'm always asking
questions trying to understand the systems, etc.  So I'm turning to the list
to get some additional information hopefully.

About five years ago we started having problems with our 1990 Westy going
through front brake pads like crazy.  They were glazing and cracking for no
apparent reason according to our former mechanic.  Since that time we've
moved and our new mechanic found one of the caliper cylinders was scored
causing the pads on that side to drag.  He also informed me the rotors
didn't have sufficient material to be turned and that they would have to be
replaced in the near future.  I decided rather than try to repair the
damaged caliper that we would replace it and while we were at it replace the
driver side too.  Our mechanic proceeded to replace both calipers, rotors
and pads.  This was about 16 months and 14000 miles ago.

About two weeks ago my wife, daughter and I embarked on a 1500 mile
driving/camping vacation.  Two days into the trip the wear indicator on our
brakes began to squeal.  I figured since we were doing mostly highway
driving that we could make it back home before we had to have it looked at.
The only real problem turned out to be driving into a quiet campground late
at night and hearing that squealing every time we tapped on the brakes.
Well, we made it home and I brought it to our mechanic and asked him to pull
the wheels and inspect the brakes because they were squealing.  His comment
was, "Did ya drive on any dusty roads?  It's probably just dust in the
brakes cause those pads should last 40,000 miles."  Later that afternoon I
got a call.  My mechanic told me that the passenger side caliper was not
releasing properly and he didn't know why.  He's now searching for the
reason.

I would like to get some feedback from the resident experts on the list.
Can you provide me with a list of probable causes for this problem?  I'll
start off the discussion with a guess of my own.  Something is keeping the
brake fluid from flowing back towards the master cylinder therefore keeping
pressure on the caliper and not allowing the pads to "bounce back" from the
rotor.  I suspect the problem is in the proportioning valve assuming that
the lines for the front brakes diverge at this point.  Of course it could be
a small blockage in the brake line to the passenger side which allows the
high pressure past but moves into a blocking position when the relatively
low pressure return flow starts.  I just don't know.

I'm prepared to replace the master cylinder, brake lines, proportioning
valve, metering valve and pressure switch if necessary.  I would also
appreciate your feedback on this.

Thanks in advance,

Tom Moritz

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