Spitfire & GT6 Forum

I've just removed this master cylinder from the pedal assembly and had a look at it. (The car hasn't been operable for years or possibly decades.) The innards look alright from the perspective of the valve on top, but the pushrod end of the piston is awfully rusty. The last two pictures show the piston end before and after I gave it a few whacks to shift it a few mm into its cylinder. So it's not technically frozen anymore, but it's certainly not going to fall out with a good shake. What do you think? Is it a lost cause, and if not, what's next?

Luke,
I think there are better ways of going. That one is going to need quite a bit of work even if you don't find pits in the bore.
If you have some reason to want that particular master cylinder you may wind up using Apple Hydraulics or White Post Restorations to sleeve the bore and save it.
All the best,
Paul

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TRF# 10423

Only you can decide that for yourself.

I bought the cheapo brake master from BPNW for $140, and learned after the fact that people have had trouble with it. Mine seems to have "dead" stroke in it before it starts to push fluid.
Will be using it as a stopgap till I get a proper one, as for which one, I was put on to the TRW/Lucas which Spitbits sells for $200, or sleeving my original.
White Post and Apple Hydraulics will rebuild sleeve and rebore the original for ~$30 or so more than the cost of the TRW. To me it made more sense to spend the extra money on this service, as at least I wont have to worry about the bore corroding in the future, so I sent it to White Post. I"ll be sending the clutch as well.
You can send them the pictures of your unit and ask them if they think it's worth saving, that's what I did, they confirmed my parts were original so i wanted to save them

AJ

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1969 Triumph GT6+, J-type OD

I've saved worse but I was really surprised that it worked. I just tried it because I couldn't afford to do anything else. I was going to start a new thread somewhat along these lines soon though, my 66 spit had its mc cannibalized and is gone; has anyone tried fitting universal/race type master cylinders for the the clutch and brakes? I know its been a few years since I've looked into anything like this but surely they are cheaper and built to better tolerances.

20 something years ago I had M/C problems. Even then there had been issues with aftermarket replacements, so I decided go with getting my M/C sleeved by Apple.

The work appeared to be very well done, but the M/C did leak when installed. Rather than ship it back to Apple (I live in Canada) I opted to rebuild it myself with an original Girling seal kit. I had originally used DoT 4 fluid, but as the leak had lifted the paint on my newly painted car, I opted to use DoT5 fluid this time around, as I had burned the warranty anyway.

This has worked perfectly ever since.

Since then, on friend's cars, I have seen both no name aftermarket M/C's leak as well as the TRW M/C's

I do feel that sleeving IS likely the best choice. BUT Apple only supplied the rebuilt M/C body. It did not have a new reservoir.
This was not an issue for me.

Just some things to consider.

The generic single MC from Wilwood, Tilton, etc will work just fine, same bolt pattern, etc.
I've had good luck with them.
But you also have an opportunity to fit a dual MC with adjustable brake balance bar, to replace the single brake MC.
I've put a lot of miles on the single MC cars in the last 50 years, had several brake issues, but luckily no crashes.
Would have been safer and better to have dual MC brakes.

Bigger motor usually means faster speeds.

But your call.

Would you elaborate on these dual MCs? Where one can get them, if installation is difficult, why they are better, etc. Thanks

It's running 2 single circuit MC instead of a single dual circuit MC. the difficulty part comes from fitting two where there was once one, and fabbing or fitting an adjustable balance bar to adjust brake bias. It CAN be better as it gives you finer control of the front and rear brake circuits for better bias adjustments, this is especially true for modified or different brakes. It can also be much more reliable as you can source newer MC with updated designs that are far more reliable than the old ones or the new crap they sell us from India.

If you design and fab your own setup it can be done very cheap with top quality OEM supplier parts (Aisin etc) from Rock Auto.

Not to mention safer. With the single line system a leak anywhere in the system makes you lose all brakes, double system you still have either front or rear brakes.

And what if I'm a complete amateur who has been making it up as he goes along for the last four years of restoration?

Carter,
Having built mounts for twin cylinders which were tied by a balance bar, I know of what you speak but
many here have no idea what they look like for our vehicles or what would be involved with fabricating one.
I don't presently have that set up, other wise I would post a photo.
If you have a photo available, I think sharing it would be helpful for many here.

Even though Wilwood does have a few photos, none are directly applicable to ur set up
https://www.wilwood.com/Search/PartNoSearch?q=balance%20bar

This is about the [url=]best video[/url] I've seen but still does not show cylinders as they would be mounted on a Spit or GT6

Steve

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[quote=clshore,1730427,1730592]
[quote=unclewolverine,1730427,1730460]
I've saved worse but I was really surprised that it worked. I just tried it because I couldn't afford to do anything else. I was going to start a new thread somewhat along these lines soon though, my 66 spit had its mc cannibalized and is gone; has anyone tried fitting universal/race type master cylinders for the the clutch and brakes? I know its been a few years since I've looked into anything like this but surely they are cheaper and built to better tolerances.
[/quote]
The generic single MC from Wilwood, Tilton, etc will work just fine, same bolt pattern, etc.
I've had good luck with them.
But you also have an opportunity to fit a dual MC with adjustable brake balance bar, to replace the single brake MC.
I've put a lot of miles on the single MC cars in the last 50 years, had several brake issues, but luckily no crashes.
Would have been safer and better to have dual MC brakes.

Bigger motor usually means faster speeds.

But your call.
[/quote]

Here is the design I stole from Rick Cline -- crude but it works. I sleeved two OE 5/8 master cylinders with some stainless steel tube I had.

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Dennis
Robert is my father's brother -- so Bob's my uncle.
RIP WWII veteran Robert C. P. 11/09/1924 -- 02/14/2021

Looks like a neat setup but possibly rather difficult for an amateur to replicate.

Dennis,
I have been toying with that idea for years. What size did you sleeve down to and where did you get seals for them?
Curious,
Paul

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TRF# 10423

Paul, and others ...
If you decide to sleeve the masters on your own, take care to make sure you buy seamless tubing.
Much of the stuff available looks seamless but is not. The outside seam is polished and can
be deceptive.

Steve