Maybe the f body guys can help with my Y body.

69 vette. Started her up the other day (car gets driven 1x a week or so) and the brake pedal goes straight to the floor, lighting up the same "BRAKE" lamp as when the e brake is on. If you drive it, it seems as if only the rear drivers side is getting any pressure, maybe the rear passenger side too (but not much). Nothing to the fronts.

However, if you pump the pedal without letting it all the way out, the car brakes normally, minus the fact that the pedal is still extended too far.

Dont have a clue about old brakes. The hard to rubber lines look good. No leaks. The booster is ancient, the line from it to intake looks ok. The resevor (sp?) was leaking a tad of fluid from the top (no idea why). I topped it off, the fluid wasnt great looking, but not horrible. I wonder if maybe i just got air into the system? Or does this sound like something else? I just really dont want to mess with bleed screws etc as the car is old, and when you work on it you tend to break rusted bolts/screws etc. So i rather have a for sure answer if possible before diving into it.

Thanks!

 

My first guess would be a bad master cylinder, but it's possible you've got air in one of the calipers. These cars have four piston brake calipers at all four wheels. Odd setup with the sealing rings on the pistons. The cast bores rust pretty bad and let them leak either fluid out or air in. Also there are a couple companies that put stainless steel sleeves in the calipers, maybe yours has had this done by now.

 

HOLY CRAP! This is like deja vu...I sware. THE SAME EXACT THING HAPPENED TO ME IN MY 74 CORVETTE! The red light that says BRAKE on the Tach came on, even though nothing was engaged. The break went all the way to the floor, and I barely had breaks. Replace your master break cylinder, and bleed all 4 breaks VERY WELL. This should fix it! Anytime you wanna talk Vettes, lemme know. Ive got a 454 in mine.

 

Thanks guys. Guess time to order a new one. I cant believe it only lasted 35 years, what crappy quality. lol.

As for talking vettes, sounds good. Nothing too special here, just a restoration/driver that will never be finished. The engine was done over with a basic 355, itty bitty cam, and cleaned up heads with valve job. Still need to redo the rochester 750, get a better intake, and some headers. The body is all finished minus a few trim pieces, and the soft top needs recovered. Used to have a hard top too, but sold that awhile ago.

Thanks again to the two of you.