Don, I'm copying this to the list to clear up any ambiguity that anyone else
might have.
The problem with the brake MC seems to be that either the bore does not wear
evenly or the pistons wear out. I suspect it is the pistons, as they always
seem to have polished edges where they seem to be riding in the bore. I
have had luck rebuilding low mileage MCs with clean bores but have had no
luck rebuilding high mileage units that have started to leak by wearing out
due to use. The magic number seems to fall in the vicinity of 75k miles but
who knows what other factors play in.
The seal kits work fine on good condition low mileage MCs but there are
fewer and fewer left. I rebuilt one low mileage unit and got eight years
out of it in my daily driver before it wore out, then rebuilds did not work.
I tried swapping in low mileage pistons and that worked in the one instance
I tried it, but new pistons aren't available.
James Nazarian
71 MGB Tourer
71 MGBGT V8
85 Dodge Ram
----- Original Message -----
From: "Don Malling" <dmallin@attglobal.net>
To: "James Nazarian" <jhn3@uakron.edu>
Sent: Sunday, October 26, 2003 8:41 AM
Subject: Re: MC rebuild vs. replace
> Hi James,
>
> I assume you mean that the Clutch MC bore must be clean in order for the
> rebuild kit to work well. Or did you mean that even if the brake MC
> has a clean bore (no pits), the rebuild kit does not work. The way it is
> worded might imply that there is something faulty with the brake MC
> rebuild kits, and they never work regardless of the condition of the MC
> bore. Even a resleeved brake MC bore will not work with a rebuild kit.
>
> So, University of Akron... tire town. I graduated from Kent State in
> '68. Bought my TR250 new in October of that year in Endicott NY (home of
> IBM). I have lived in or near Endicott NY since then. I grew up in
> Tiffin OH. My family was from Cleveland, so no one is left in Tiffin now
> but childhood friends. Long time ago... seems like only yesterday...
>
> :-)
>
> Don Malling
>
> James Nazarian wrote:
> > The shop that I used to work for had a couple of guys that have been
> > wrenching on these cars since the dawn o time and they have concluded,
from
> > experience, that the clutch MC seems to take a seal kit well and return
to
> > service, while the brake MC rarely does so. My limited (10+ years)
> > experience agrees. All of this is provided that the bores are clean,
which
> > is not often the case on a car that has spent a long time laid up.
> >
> > James Nazarian
> > 71 MGB Tourer
> > 71 MGBGT V8
> > 85 Dodge Ram
> > ----- Original Message -----
> > From: "Don Malling" <dmallin@attglobal.net>
> > To: "Paul M." <rowman22001@yahoo.com>; <mgs@autox.team.net>
> > Sent: Saturday, October 25, 2003 6:04 AM
> > Subject: Re: MC rebuild vs. replace
> >
> >
> >
> >>As someone else posted the real question is whether they are rusted or
> >>not. Most likely they are. That's what tears up the rubber seals.
> >>
> >>It's been my experience that you can't usually get the pits out by
> >>honing the cylinders, but if you can, great.
> >>
> >>In my opinion resleeving them in brass or I suppose stainless is better
> >>than new. They don't rust again. Seems I heard there were problems with
> >>stainless, but maybe I'm making it up. Like there were problems with the
> >>stainless staying in place or something -- maybe I'm making it up. You
> >>better ask. I can't imagine you need more than brass. They're just
> >>rubber seals moving against it.
> >>
> >>Anyway, you might try www.brakecylinder.com. I had my TR250 brake MC and
> >>clutch slave cyl resleeved in brass and they did a nice job. They came
> >>back bead blasted and looking like new. The car is in a frame off
> >>restoration, so I have not installed or used them yet. I think Peter C.
> >>(the lever shock guy) at www.nosimport.com recommended them. Anyone
> >>Peter C. recommends is good enough for me. Peter C. is top shelf in my
> >>opinion -- but that's another story.
> >>
> >>Single diameter bore MC's are $65, and dual diameter bores are $110. The
> >>TR250 was dual bore. Not sure about the MG. I'll have my MG's done there
> >>when I get to it. I think new MG MC are expensive $170 to $200.00
> >>depending on the year. The clutch MC on the TR250 is aluminum, so they
> >>don't rust. Not sure about the MG clutch master.
> >>
> >>I didn't do the wheel cylinders but I'm thinking about it. Resleeving is
> >>$50 each and buying new is half the price, but the resleeved won't rust,
> >>so is the work in changing them worth $25.00?? But then I already have
> >>the new ones... Resleeve the new ones?? Hmmm....
> >>
> >>NFI yada, yada...
> >>
> >>Don Malling
> >>
> >>
> >>
> >>
> >>
> >>Paul M. wrote:
> >>
> >>>My 1971 MGB is losing fluid from both the brake and
> >>>clutch reservoirs. Somewhat slowly, but also somewhat
> >>>increasingly. My suspicion is that it's the master
> >>>cylinders.
> >>>
> >>>What is the current consensus on rebuilding vs.
> >>>replacing the master cylinders? Repair kits are so
> >>>cheap, but I'm going to be vintage racing this car and
> >>>I want to make sure the brakes are better than
> >>>tip-top. Any thoughts? And am I correct in assuming
> >>>that if I rebuild/replace the clutch master cylinder I
> >>>should also rebuild/replace the slave, whether it
> >>>seems to need it or not?
> >>>
> >>>Thanks in advance,
|