John:
Assuming that your DPO was competent in replacing the MC, the
next item to check would be the PDWA assembly. This is the brass union
mounted on the body near the fuel filter. It has 4 brake lines going
into it, and one electrical
connector (assuming that it is even hooked up).
Most often, the o-rings inside get stale, and fluid starts
bubbling up through the electrical connector. This can be precipitated
by purging the brake lines on the front or rear of the car which causes
the internal shuttle to be displaced. This disturbs the seals, and a
leak is the result. If the o-rings are shot, then recentering the piston
will do no good, it will still leak.
The Bentley manual gives a procedure to recenter the shuttle
that I have never been able to make work. The procedure I use is to
unscrew the PDWA switch (Electrical thingy in the center of the PDWA)
and insert a small screw driver into the hole, and "feel" where the
piston is, then pry it back into the center position.
Even if this works, your o-rings are living on borrowed time.
Best to take this opportunity to replace them. Disassembling the PDWA is
trivial, and you can use o-rings from the hardware store. They are
metric (2x8mm as I recall) and cost a few pennies. I installed a fresh
copper washer from the hardware store as well. No problems since.
Vance
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net] On
Behalf Of John VanNorman
Sent: October 31, 2005 7:34 AM
To: 6pack
Subject: brake fluid leak
Another question for the list. I was doing some work on the car and had
the rear end up in the air with the front down
(I would note that this is the first time I've done that. 80% of the
time I've been working on things near the front
of the car and only have the front end jacked up. And when I've had the
car completely off the ground, I put the rear
end up last). So now to the problem. After doing the work, I noticed
brake fluid on the garage floor. On the metal
frame near the fuel filter I could see brake fluid, but when I looked
around the master cylinder and the servo, I
didn't see any obvious signs of leaking on either of them. My stupid
question of the week is this - would jacking the
rear of car up have caused brake fluid to leak somehow? I would think
not and maybe it was just a weird coincidence.
Lastly, since I'm a newbie, what would you recommend checking out? I
would add that if I remember correctly, the
previous owner installed a new master cylinder just a few years ago (I'm
writing this at work and don't have my records
on me right now - don't tell the boss!).
John V.
74 1/2 TR
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