i have fitted my 81 with new brake lines and a new master cylinder. ive bled the brakes as far as they could be and the pedal is still soft. any suggestions? thanks :angry:

Did you bench bleed the master cylinder first? If so, sometimes it takes almost forever to get all of the air out. Just don't let the master cylinder get low or you have to start over.

The M/C needs to be put in a vise and pumped with a long screwdriver or something that will fit in the bore. Pump the piston until all the bubbles are out of the fluid. Fill the resevoir with fluid and run lines from the 2 ports back into the resevoir. Make sure the lines stay below the fluid level while pumping. Eventually all the bubbles will disappear. Then you are going to have to bleed the wheels again. I use a hand vacuum pump, but even those can have issues at times. When you installed the calipers, did you make sure the bleeder screw was at the top? If not, then you will never get all the air out. Some guys just open the bleeders and let them gravity bleed. This works, but takes at least a day.