Brake Problem

[Yook]

On my '78.. I can't seem to figure out whats wrong with the
brakes. I'm missing the first stage of the brakes. When I
press on the brakes, it goes way down and starts braking
in the second stage. I took it to a repair shop, and they
checked the brakes.. which seem to be fine, and replaced
the part that holds the brake fluid.. bled all of the brakes
a few different times, replaced the proportioning valye,
but nothing seems to remedy the problem. Any ideas?
Anybody here had this problem before.. Thanks!

 

[Vette/Berlina-coupe]

-if you paid by Mastercard/Visa I would make a big stink about this unsafe hazardous repair-job done for you in good-faith; --nothing more critical than proper braking action; --your Credit-card company should imdemnify you on this expense, either making the shop do it right (they may not have primed the Master-cylinder properly prior to installation?, or perhaps the proportional-valve is not adjusted correctly?), or refund your money so that you can go to a MrGoodWrench sort of expert on the C3's braking-system! Other than this avenue, including lodging a complaint with your "State Bureau of Automotive-Repair" (something like that, -look it up), perhaps there is someone here that can better put their finger on just what has gone wrong, so that you can get it put right asap!!! Oh, and when you do finally get it fixed to operate like new, please let us know the solution (you can comment further right in your original message-box by clicking on "edit")... ~Bob vH
:bash:dance

 

[pax]

Welcome Yook,
Check the calipers, lines etc. for any weeping of fluid....if fluid can get out, air can get in.
If there is too much movement at the rotors they can pump air into the system.
Also, I have learned here that sometimes when people rebuild the calipers they leave out the spring behind the pistons which can lead to this result.
If you could be more specific re. how long (miles) is it after you bleed the brakes does this problem occur, perhaps someone here would have more ideas.
john

 

[DDLS3]

C3 brakes are a PIA with so many things that can and do cause trouble. Just to rule it out, check your brake booster. Run the engine a few minutes then shut it off. After a few minutes go under the hood and remove the vacuum line from the booster, there should be a loud hiss as the vacuum comes off the diaphram. If there is no hiss or a very weak one then you have a leaking booster which will require replacement.