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'76B Brake Servo again + DOT 5 question

To: mgs@autox.team.net
Subject: '76B Brake Servo again + DOT 5 question
From: Florrie & Allen Bachelder <bachldrs@swva.net>
Date: Mon, 12 Jul 1999 10:28:27 -0400
Hi List -

' Got no responses to my question below - perhaps nobody has dealt with
this before - but as our RBBs age, this may become a more frequent concern.
I figured it out myself and thought I'd pass my findings on - since this is
not in any of the manuals I have.

The 'nose' of the brake master cylinder fits into a cup-shaped rubber seal
in the servo. (Or rather, it does not - hence the problem).  Due to the
position of the mounting studs, the MC cannot be twisted into the seal.
BUT, the seal can be gently pried out of the servo.  Furthermore, there is
a metal cup containing it in the servo that more-or-less falls out with it.
SO... the solution is to remove the new rubber-cup seal from the rebuilt
servo, place it on the 'nose' of the MC first, then assemble the metal cup
on the seal, and finally - bolt the whole assembly right up to the servo.
No problem.

Now comes a new question.  Acting on enthusiastic advice of A Person Who
Should Know Better (but who will remain anonymous as he is also a good
friend), I flushed out my system thoroughly - switching to DOT 5.

Bad news: not until afterwords did I read the disclaimer that came with the
new MC: "warrenty void if DOT 5 is used".  8^(

Double bad news: less than 300 miles later I found my left front wheel
soaked in brake fluid.  ("Good news" - DOT 5 didn't ruin the paint on my
new Dayton wire wheel - whoopee!)  I've rebuilt calipers in the past - as
preventive maintenance, and on ones that had siezed, but in 15 years I've
never had a caliper leak.  A rear wheel cylinder, of course, but never a
caliper.  Methinks DOT 5 is the culprit.

So now I've got another set of calipers to rebuild. (Aarrgh...)  QUESTION:
will I have any problems flushing/switching BACK to good old DOT 4 Castrol
LMA?

TIA

Allen
--------------------------------------

>Date: Sun, 4 Jul 1999 19:15:06 -0400
>To: LBClist
>From: Florrie & Allen Bachelder <bachldrs@swva.net>
>Subject: '76B Brake Servo
>
>Help, Listers -
>
>I got my '76 B brake servo rebuilt by Apple Hydraulics - and while I'm at
>it, I'm replacing clutch and brake master cylinders...
>
>Problem: new master cylinder... won't bolt up to the rebuilt servo.  Servo
>came back from Apple with a rubber seal around the push rod (that engages
>the master cylinder piston) that sits flush with outside of servo.  But
>the master cylinder has a 'nose' that protrudes perhaps 1" into the servo.
>This seal popped off easily enough, revealing another rubber seal (like
>the old one) with radial slots - designed to slip over the protruding nose
>of the mc.  But even in this configuration, the  mc will not slide into
>the servo.  Yes I can force it enough to get nuts on the studs and by
>tightening them, I suppose I could pull it together - but I hesitate to
>try something like that unless I know it's the way to go.
>
>Any advice?...
>
>Thanks much in advance for any help you can spare me.
>
>Allen
>
>

******************************************
         Allen H. Bachelder  =iii=<
         Sinking Creek Home for Wayward MGs
         New Castle, VA 24127
         USA
         540/544-7333
******************************************



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