After purchasing about 5 master cylinders from NAPA Orielly's and Auto Zone. All of them leak, but what was to be expected. So I was going to purchase a better master cylinder. I would like for it to be as factory looking as possible. Just wondering if the ones from Ground Up were working good. I did find the one from Just Power Brakes the "309" master cylinder but not sure if it is the correct one for my car. Maybe I'm making it harder than it seems but if someone could give me some help I would greatly appreciate it.
:beers:

Where are they leaking from?

I believe the '69or '70 corvette had a disc/disc manual setup with a 1" bore that should be OK for your application. Don't use a drum/drum manual M/C, while the bore may be OK for manual, the resevoirs won't be large enough volume.

You may need a 10lb residual pressure valve for the drum lines as the M/C I referenced above was for a disc/disc manual.

They leak from the cap. Can I not buy what went on my car originally anywhere without having to change a bunch of stuff. Does GM not reproduce the master cylinder? It's a factory SS car with manual disc drum brakes.:confused:

To my knowledge, Chevelles in '69 never came manual disc/drum from the factory... is someone spinning you a yarn?

Find a good store...NAPA should be able to help you and purchase an AC Delco Master 18M72. It will be the most expensive one, but it will be identical to factory and work very well. It is an 1-1/8" bore for power brakes. I did not know that a factory '69 came without power brakes: Interesting! I have had trouble with M/Cs and will never buy another A-1 Cardone, but the AC Delco ones are very nice and I have never had a problem with one.

Unless someone has changed it in the past but the vin plate on my car has a paint code of 76 that matches the vin number. No power steering no air.:confused::confused::confused:

What about the vacuum fitting that should go to the brake booster? Is it capped, pipe plugged? I don't have a pic but you can probably find one on a repro site (like ss396.com) for an idea of what it looked like. Bottom line, if you have 1-1/8" bore M/C, it was intended to be used with a booster, I.e power brakes.

Another thing you can do it look at the delay valve and the configuration of the hard lines from M/C > delay valve > prop/distro block and determine if that looks all factory also.

I'll have to look at the vacuum. But you can tell by looking at the delay valve that is old as dirt I had thought about replacing all of that. Just disgusted right now. :sad:

I wouldn't 'replace' the original delay valve, just hit it with a little brake cleaner, maybe some steel wool/scotch brite pad and it'll look decent again. Mainly I was getting at non-factory bends or the line coils not being present. Without a pic of the factory setup with booster, someone could possibly just bend the lines manually, but to make up for the size of the booster, something wouldn't look right. It was common for folks to remove the booster (or subsititute for a smaller diameter one) for tall valve covers, if you have a BBC.

Maybe it makes more sense now being that it does have tall valve covers on it. :hurray:

Would it be ok to use the Delco part number that he gave me then? The master cylinders seem to be working except leaking out the cap. So I'm at a stand still and tired of buying master cylinders.