I have a 69 chevelle w/ stock front calipers and metric calipers on the back using a early 70's vette m/c. I had the stock distrubtion block at first and in a couple of blocks the brakes where applied, I changed the dist. block out and used a t- fitting and coupler for the back and set out again. we got twice as far,but it still locked up. What am I doing wrong?? Not enough clearance in the pushrod to m/c?
Thanks For any advice!!!!!!!

Although you did not mention changing the master in your post, that would be the first place I would check - master cylinder pushrod clearance. There is a compinsating port in the master that allows fluid to return to the resivior. If it is blocked, as you drive the car the fluid warms up & expands. It has to expand somewhere...causing the brakes to apply. Good luck!

Brain, I did change the master cylinder and I am using one from a 71 vette that had 4 wheel disc brakes.
I reused my pushrod(power drum rod) and have shortened it and re threaded it. At first I had trouble bleeding it-rod was to long -corrected that things looked good until the drive.
How does one know what proper clearance would be???
Thanks for the reply!!!!!

there should be a paper thin gap between the push rod and the back of the mc. i used a piece of clay on the tip of the rod, bolted down the mc and then checked the squeezed clay. i actually had to put washers under the mc where it mounts to the booster to get proper gappage. i could have shorted the rod but didnt. i only needed one or 2 washers on each side. works fine now

PROBLEM SOLVED!!!!!!
I found that the pedal was being held up by the brake lite switch and had the plunger to the master pushed in. DAA graemlins/clonk.gif
Many thanks to all!!!!!
One set from TRACK TIME graemlins/hurray.gif