I am having brake issue on my 1970 duster

Brake issues are a pain, going thru the same thing, brakes fine, sit in the garage all winter, drove around the block, lost the brakes.
Leaking from the back of the master cylinder, easy fix, yeah right.
What the fu** master cylinder is on this thing, third time was a charm at NAPA, the PO put a 440 in the 85 D-150 and used an earlier master/booster.
Hooked everything up, bleed the brakes, the stupid PO had the brake lines backwards, and they are different sizes, so waiting on Thursday to come for adapters to come to switch the lines.
Fun times............