Did the 67 M/C have bleeder screws?

[Roger Coen #30751]

I have seen both. What is correct? What is/are the casting numbers?

[Jack H.]

Re: Did the 67 M/C have bleeder screws?

Bleeder's were a part of the MC assy until somewhere in the mid-late '70 era, if memory serves. Cast number will be on the RH side with the MC mounted on the firewall.

[John H.]

Re: Did the 67 M/C have bleeder screws?

Roger -

The '67 master cylinder (both manual and J50) is casting #5455509, has bleeders, and is stamped "DC" on the machined surface at the front.

[Roger Coen #30751]

Are you guys sure????????????

FWIW I just finished looking at all the 67's on Pro Teams website (by NO means the offical answer) and all cars but 1 had M/C's w/o screws.

What does the JM say? Joe Lucia?

[Joe L.]

Re: Are you guys sure????????????

Roger-----

ALL 1967 Corvette master cylinders had bleeder screws. Manual brake and J-50 power brake cars used the 1" bore, "DC"-coded, GM casting #5455509 master cylinder. J-56 cars used a 1-1/8" bore, "PG"-coded, GM casting #5450346 master cylinder.

These same castings were used for C3 cars. However, beginning in 1968, the "DC" coded master cylinder was used only for manual brake cars. The "PG"-coded master cylinder was used for power brakes, either J-56 or J-50. There were 2 castings used for these, though: the GM #5450346 and GM #5466309. Through 1972, all master cylinders continued to use bleeder valves.

Beginning in 1973, or so, the bleeder valves were eliminated from both PRODUCTION and 67-72 SERVICE master cylinders. The same castings continued to be used, however; they were just not machined for the bleeder valves. Many of the 73+ style original Delco master cylinders without bleeder valves were rebuilt by commercial rebuilders and entered their stocks as applicable to 67+ Corvettes. So, 67-72 Corvettes may be found with original Delco master cylinders without bleeder valves. But, they didn't originally come that way.

About 1982, or so, Delco-Moraine ceased manufacturing the original style master cylinders. The master cylinders were then "outsourced" to another brake manufacturer, but continued to be sold under GM/AC-Delco part numbers. These master cylinders often have the words "Made in U.S.A." prominently debossed on the side of the master cylinder. To my knowledge, NONE of these have bleeder valves and, for sure, NONE of these are original to any 67-72 Corvette. Absolutely, positively not.

[Michael W.]

Re: Are you guys sure????????????

Just for interest's sake, bleeder screws were present until the end of 1973 production. 1974 was the first m/y without.

I can't imagine why Pro Team would not get this detail right.

[Page C.]

Re: Are you guys sure????????????

Hi Everyone,
There is a great article with lots of pictures on the 1967-72 master cylinders in Vol 17 # 2 of the Restorer Magazine written by Hans Norberg.
Hope this helps,
Page Campbell

[John H.]

Re: Are you guys sure????????????

>

You've got to be kidding! Pro-Team as an originality reference? See my post above for what the TM&JG says (I don't make this stuff up), and see Joe's post below for the detail. 90% of all 35-year-old Corvettes have had the master cylinders replaced, most well in the past, by owners who had no interest whatsoever in preserving the original one and "just wanted it fixed"; the service replacements didn't have bleeders, and the cap on the service replacement was different than the original as well. Really

[Patrick H.]

Re: Are you guys sure????????????

I heard they've got a really neat 2x4 57, though.

Then again, I think it started out life as a stovebolt six Powerglide...

Patrick

[Roger Coen #30751]

Don't get em in a bunch John

That was the only place I thought of to look at several right away. If you, Joe, JH et al say so I BELIEVE!!!

Thanks for taking the time to respond. All of you.

Roger