Date:         Sat, 13 Apr 2002 09:48:13 -0700
Reply-To:     DaveC <voicebox@DNAI.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         DaveC <voicebox@DNAI.COM>
Subject:      Re: Help...Brake Question
In-Reply-To:  <LPBBJLCMHJOPCLHMMFECEELLDNAA.jbrschawn@earthlink.net>
Content-Type: text/plain; charset="us-ascii" ; format="flowed"

>Can some one please help?  Here's the story as told by the digi-wife:
>
>"First there were brakes and then they were gone... no matter how much you
>pumped they wouldn't come back."

A bit of brake diagnosis from the Bentley VW Golf, Jetta, etc. manual
[bracketed comments mine]:

"Test the m/c by holding the pedal down hard with the car stopped and
the engine running. The pedal should feel solid and stay solid. If
the pedal slowly falls to the floor and there is no evidence of fluid
leaks in the system, then the m/c is faulty and should be replaced.

...test the vacuum booster by first pumping the brake pedal a few
times with the engine off, and then holding the pedal down. When the
engine is started, the pedal should fall slightly. [If it falls
significantly, there is a problem in the vacuum circuit.] The booster
diaphragm rarely fails, but leaks in the vacuum line or a faulty
check valve will decrease the vacuum assist. Check the valve by
removing it from the booster vacuum line and blowing through it. Air
should pass through in the direction of the arrow on the check valve,
but not through the opposite way. On cars with diesel engines, vacuum
booster problems may be caused by a faulty vacuum pump. If brake
fluid id leaking into the booster from the master cylinder, the
master cylinder is defective and should be replaced." [If all other
vacuum components check out, the diaphragm is bad and should be
replaced.]

Descriptions such as existence and location of check valve, etc. may
or may not be appropos to Vanagons (I couldn't find any mention in my
Vanagon docs), but the rest is generic among all VW models w/ power
brakes.

As was suggested before, rear brakes must be adjusted fully for the
brakes to function normally. Auto adjusters may be malfunctioning
which keeps the shoes far from the drum surface, requiring large
pedal travel to get the shoes where they need to be to do the
stopping work. The result is that the pedal falls way close to the
floor when pressed the first time. Subsequent pumping results in a
higher pedal.

Good luck,
Dave
--
Dave Carpenter

Whatever you wish for me,
May you have twice as much.

"Sometimes I think we're alone in the universe, and sometimes I think
we're not. In either case the idea is quite staggering." -- Arthur C.
Clarke