Master Cylinder Problems

The master cylinder on my '67 Belvedere is leaking like the Missouri river. Four wheel manual drum application. The M/C has the four studs that go through the firewall with the nuts on the passenger compartment side. I can't find ANY replacement M/C's, even NOS ones that have the studs. Do I have to remove the studs from the old M/C and install them in the new one? The '67 FSM does not address this at all. The '67 parts book does not show a listing for the studs as a separate item. In fact, the photo in the parts book for the manual setup shows the pedal bracket that the studs go through, and the M/C, but no studs in the M/C. Can anyone shed some light on this?

Can you rebuild your old one? It isn't hard if you can find a kit.

Yes….i’ve pressed out the old studs and instalked them on the new m/c on many occassions.

What I'm worried about is that it's the piston seal at the input end that is leaking. When I've encountered this before, the combination of brake fluid and atmosphere has corroded the bore to the point that it's junk. But I'm going to pull the M/C tomorrow and see what the bore condition looks like.

That's what I needed to know! I have a rebuild kit on the way but if that route proves unworkable, I think Mr. Press will be my friend! Thanks again.

Have the MC professionally rebuilt & the cyl. sleeved.

This is the best solution. I've used this company near Winchester Va. with success on several occasions. It will last longer than we will. https://whitepost.com/brake-sleeving-rebuilding-services/

I found NOS M/C's with a Google search. If mine is unrebuildable, I think I will go with NOS and transfer the studs.

Well, I got it out this afternoon and yes, it has serrated head studs. I honed the bore a bit and it cleaned up really well. I think a kit will make it.

Fwiw...The studs will tap out easily with just a small hammer it the rebuild doesn't work for whatever reason...

Thanks to all who helped.

i did just that when i replaced the master on my buddy's 70 super bee.
it was an original drum brake car, but i converted it to discs.
the original drum master was a 1" bore, but i put a 1 1/32" bore master on it when doing the conversion.
it stops 10 times better now !

FYI: it would do even better with a 1" bore or smaller but would require a tiny bit more pedal travel

you are correct. however when the swap occurred, he had already purchased everything, so i just installed it.
i told him if it were me, i would have gone with a 15/16 [i am a wimp] or 1" master.
after the swap was made, he was super happy on how good it stopped he didn't want to change anything, so i left it as it was.

mymain reason for commenting was so that others would be aware of the differences

one of the best stickies on here is the "feets brake article".
a mandatory read for anyone wanting to do brake work, other than just replace components.
commenting is a great way to remind others who do not know, [me ] as well as reminding those who have forgotten. [me again ]

Could you point me to it, i have a friend that may benefit from it

it's in the handling section, sticky at the top.
"everything you ever wanted to know about disc brakes" [or something like that] from member FEETS.