Brake Question ?
Thread Starter
4th Gear
Joined: Oct 2006
Posts: 4
Likes: 0
From: Mattoon IL
Brake Question ?
I have a brake question I am hoping someone can help me with, I have been restoring a 76 vette, I have replaced every componet of the brake system, all new calipers, stainless brake lines, new master cylinder, new proportioning valve, it is all new, the bleeding has been completed, (master cylinder was bench bled) here is were my trouble starts. went to take it for a test drive, applied the brakes and both front calipers have locked and would not release, I cracked open the bleeder valve on the left side and it released right away, was able to turn roter by hand. I am not sure how the proportioning valve works, like I said it is brand new, since it is a valve is it possible for it to lock the front brakes? could the problem be the proportioning valve? any & all help is apprecaited, thanks in advance.......
Racer
Joined: Jan 2004
Posts: 263
Likes: 1
From: 20,000 leagues under the sea
Did you check the push rod that goes into the master cylinder and make sure that it is not adjusted to long? The rod should not be pushing the piston into the master at all (the piston must be able to return all the way to the retainer clip when no brake is being applied). Ask me how I know.
Dave
Dave
Thread Starter
4th Gear
Joined: Oct 2006
Posts: 4
Likes: 0
From: Mattoon IL
Thanks for your replay 68raggtop, maybe a dumb question, how would I know if I am getting to much travel on the push rod, is there an easy way to check this , again I appreciate your help, has been a long restoration project, I am done with all of the mechanical restoration and all of the interior restoration, paint will be next, I am getting anxious to test drive it........
Racer
Joined: Jan 2004
Posts: 263
Likes: 1
From: 20,000 leagues under the sea
From inside the car, under the dash where the push rod attaches to the brake pedal is a jam nut. From there, it goes forward to the piston. If the brake pedal can be depressed, moving the push rod into the master cylinder without the piston itself moving, then your should be ok. There is a spec for how much pedal travel you should have in the assembly manual (it's .06 - .25 free pedal travel for 68's). If the push rod is to long there will be no free pedal travel. Hope that helps. 
Dave
Dave
