[vettestr]

Check your balance bar for being centered first of all (you can do the front to rear bias with an adjustable bias valve). Then make sure you are allowing the M/C piston to completely return to home. For now leave a little extra free pedal movement. Too chase problems leave a good 3/4 inch of free play on the pedal to ensure each master cylinder is returning to the home stop.
If M/C does not have enough free play it has a internal passage that never closes and no pedal pressure can be built just like problem you have now. Then re- bleed the heck out of system. good luck, it will be fine!! Jeff C