I have 70 chevelle sitting in our shop that I would like to burn to the ground. It came in with a master cylinder leaking. Great no big deal. Well after removing the master it had destroyed the booster. No problems. Well everything's back together and the pedal just doesn't feel right to me. All the parts came from classic performance. The new master was bad so they sent us a new one. Well after installing today the pedal just seems to run out of travel. The car stops but the pedal seems to be about an 1" from the floor board. I have adjusted the booster rod bleed everything several times and adjusted the rears up. But just doesn't seem to have a really good pedal. This is a disc/ drum car. Is this just a characteristic of the 70s or is thee something we may be over looking.
Thanks

Did the booster come with two different length push rods, and did you se the long one?

yes it did one was 2.5 and the other was 4 for the deep bore master. We used the 4. Still spongy

I can tell you that I have an all stock disc set-up in the front and a WilWood disc set-up on the back. I just changed my Master cylinder, booster (rod and all), front rotors, calipers, pads, bearings and rubber lines (again all this stuff was stock, I didn't do anything but bleed the rears). After a bench bleed (using the little tube kit), brake bleed (RR, LR, RF, LF) and making sure my Master cylinder was full I have about 1 inch before they start grabbing. I couldn't get my pedal an inch from the floor if I tired. My cowl hood is not hooked up and the little flapper door near the windshield flipped forward the first time I needed to hit my brakes, needless to say they work great.

I wish we could get the same results. I just cant put my finger on the problem. This is a stock disc/drum set up. I will take alook at it again in the morning.
Thanks for your help.

Maybe the master is too small of a bore (should be 1-1/8" I believe for power front disc)? Should be able to just unbolt the master from the booster and pull it out a bit to check/measure the piston if you need to check. A smaller (1") bore for a manual disc or drum car would lead to a long-ish pedal and somewhat vague feeling brakes due to lack of volume.

Of course, I'm still trying to sort through the brake issues I'm having w/ my Camaro, so maybe you shouldn't take any advice from me.... ;)

Thanks for the reply. Yes we had thought of this also. And your right it does use the 1 1/8 bore. unfortunately this is the master we are using.
Thanks Tim

Tim,
have you checked the rear wheel brake adjustment?

david

David, Yes the rears are adjusted. to reduce pedal travel.