I put all new brakes on my 70 Dart. Disc front and drum in back. All new lines from fine lines. New master cylinder, new calipers in front, a used combination brake valve# MD2268 in the classic parts catalog.. I bench bled the master and opened the bleeders on the front but no fluid will come out even after pumping the brake pedal. What shouls I check. Thanls for any help.

It sounds like the master cylinder is not bled correctly. Are there little bubbles in the master cylinder bowls after pumping the pedal? If so you still have air in it. You can bleed it on the car this way -

If there is a little "pin" valve on the prop valve pull it out & hold it out with a pair of vice grips & see if it'll bleed. If not then undo the front line at the prop valve & see if you have fluid