junk master cylinders

[Gene M.]

I've been thru 3 master cylinders in the last week. All three were GM castings. Two rebuilts and a new Delco. The Delco was made in china, no wonder it was junk. All three would bench bleed the front cylinder with good pressure. The rears were dead as in no pressure, no air, no fluid. But still no action/pressure from the piston. The only way I could get fluid to pass was via vacuum using the Mighty Might vacuum pump. This is a 1" bore for a non power brake '72. Only one rebuild had bleeder screws.

Anybody found a good replacement master cylinder? It does not have to be for flight judging just functional.

[Philip C.]

Re: junk master cylinders

Gene since nobody jumped in, I would contact the guys at Corvette stainless brake tech line 305-256-8077, in all the years Ive been playing around, I cant remember having that prolbem with a master, Iam sure your benching it right, with lines going back into the master and under the fluid. Phil 8063

[Michael L.]

Re: junk master cylinders

Hi Gene
I second Corvette stainless they have quality parts
Thanks Michael

[Joe L.]

Re: junk master cylinders

I've been thru 3 master cylinders in the last week. All three were GM castings. Two rebuilts and a new Delco. The Delco was made in china, no wonder it was junk. All three would bench bleed the front cylinder with good pressure. The rears were dead as in no pressure, no air, no fluid. But still no action/pressure from the piston. The only way I could get fluid to pass was via vacuum using the Mighty Might vacuum pump. This is a 1" bore for a non power brake '72. Only one rebuild had bleeder screws.

Anybody found a good replacement master cylinder? It does not have to be for flight judging just functional.

Gene-----


I think you'll find that just about any new master cylinder you find, regardless of how branded, will be from the same manufacturing source. However, it's worth looking into the other major brands including Wagner, Raybestos or Bendix.

The fact that you're having the same problem with THREE, separately sourced master cylinders seems VERY strange to me. In any event, I don't think the problem is with the master cylinder castings or machining. I think the problem is with the pistons and/or seals.

1967+ Corvette master cylinders through about the 72-73 period were equipped with bleeder screws. After that, all, including SERVICE for 68-72, had no bleeders. No current new replacements have bleeder screws EXCEPT for those reproduction units now available. However, I believe they are manufactured in China, too. So, of your 2 rebuilds, one must have been a 68-72 unit and the other a 73+ unit.