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Murphy's Law Repealed?? (was) Re: Front Disc Brake Cylinders

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Subject: Murphy's Law Repealed?? (was) Re: Front Disc Brake Cylinders
From: "David R. Conrad" <conrad1@gte.net>
Date: Tue, 24 Feb 2004 19:36:38 -1000
List:

Thanks to those who responded to my request for
information to refresh my memory on the difference in the
two types of front wheel cylinders used on the front disc
brakes for our cars.

I knew they were different, between "inner" and "outer",
but had forgotten the specific reason.  Further, my old
ones, from my parts "morgue", DID have two of each type.
Upon reexamination, I found that one that I thought, had
both "V" type seats for the connections, had, in fact,
(what I term) a "W" type seat, made hard to discern by
crap/corrosion.

The Murphy's Law part:

Although there was a "50/50" chance that my leaking one
would be the type for which I had a new one for
replacement, I was certain that Murphy's Law would
predicate the contrary case.  Much to my (pleasant)
surprise, the cylinder which was leaking was the outer
one, the one with the differing seats for the connectors,
and the type I have a new one for.

The fittings to the cylinders tend to weld themselves to
the tubing, after time, such that  in unscrewing the
fitting, there is a tendency to shear the tubing in
torsion, where it comes out of the fitting.  To remove the
cylinder, I had to remove three such connections.  Two of
the three fittings removed, resulted in shearing of the
tubing.  The tubing from the junction to the flexible hose
remained intact.  My further good fortune was that, in
removing the two pieces of tubing from that cylinder, only
one piece of tubing sheared off the fittings on both ends
(rather than one fitting on each piece).

Now, all I have to do is simply replace that one leaking
cylinder with my new one, and replace the one destroyed
piece of tubing, bleed it, and have a leak free front
brake system.

I already have, (as stated in my original email), new
tubing to replace all the tubing for the front discs,
which I intend to do, "some time".

That may be Murphy's plan:  to tempt me to do just
that...  ;-).

Dave
'68 1600
Kailua-Kona





"David R. Conrad" wrote:

> List:
>
> I need a reminder.
>
> Before "getting into" the process of  correcting a
> minor leak of the right front brake hydraulics, I would
> appreciate the answer to the difference between the
> inner and outer cylinders.
>
> While "I'm at it", I plan to replace the steel tubing
> at each front wheel, because the existing tubing is
> badly rusted.  I have the new tubing to replace the
> existing, I purchased several years ago.  It is 'pre
> bent' into proper configuration, together with correct
> fittings and tube flares.
>
> I have one 'brand new, pristine' wheel cylinder.  I am
> hoping that it is the correct one for the one which is
> leaking.  "50/50 chance".  It is the one which has a
> "V" shaped seat at the bottom of one bore, and what,
> might be described as a "W" shaped seat, at the bottom
> of the other bore.
>
> Now, what really causes me confusion, is that I
> examined the 4 cylinders I removed when I last did a
> front brake overhaul.  Three of them had "V" shaped
> seats on BOTH ends; while only one had had a "W" shaped
> seat on one end.
>
> That suggests that I had a 'wrong' wheel cylinder,
> through the entire period of one front brake overhaul
> 'cycle'.  At this point, I don't know what's in there
> now.
>
> How should they be, and can they be installed
> interchangeably without getting into trouble?
>
> Appreciate any help!!
>
> Dave






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