have been messing with what i thought was a simple project all afternoon. have a 68 camaro that originally had standard drum brakes. it was upgraded to power assisted drum brakes. I did not drive it for about 4 months and went to use it and discovered I had very little brake pedal. No fluid leaks and the master cylinder was full. I figured it must be an internal master cylinder problem----cheap, easy fix. Took the old one off, not knowing for sure what would replace it, and carried it with me. A 1969 master cylinder seemed to match perfect, so i bench bleed it and bolted it on. lines were perfect and started bleeding the lines. Well two hours later, still bleeding and the pedal level is still at about the same postion it was with the old master cylinder. no leaks, no fluid loss, just can not get but about an inch of pedal at most. I now think think the old cylinder was probably ok as this one is giving same problems. The brakes will lock on dirt....and all 4 wheels are braking------just no pedal as it is on the floor when this happens. Thanks for any help offered!!