A friend and I just finished a complete 4 wheel disc conversion on his 67 ss/rs and cannot seem to get the pedal to feel like the brake lines have pressure. We have a new master cylinder, new rubber hoses, etc. These are manual brakes, no power. The pedal just travels to the floor. We have bled them and are getting plenty of fluid out the bleeder valve,. It seems that when you try to pump the brakes the fluid is moving back into the line like a suction. we are getting zero pressure.

What could cause this?

Thanks,
Aaron

 

Is this a M/C from a kit or did you go out and get it ? 4W disc M/C's have large chambers and an increased piston bore for moving more fluid and putting more pressure in it.

Another thing is the proportioning valve. If you use the stock rear drum piece, it won't work right. Better off putting in an adjustable unit from Summit (get the summit, its a re-packaged wilwood).

Another thing is if you bench bled the M/C before putting it in the car. Its GOT TO be done off the car (put it in a vice, fill it w/ fluid, and use the bleeder kit they come with and push the piston w/ a screwdriver to cycle fluid thru it).

If after all this it STILL isn't working, something else is wrong...like the pishrod on the m/c is missing or something. ITs been known to happen - but people get bad remanuf M/C's from the parts store....so buy a BRAND NEW one for a few bucks more...
Bled them RR, LR, RF, LF in that order, right ?

...just checking...