So after swapping in my new motor I am having a problem with my brakes. I can build pressure in the lines by pumping the pedal but after a while the pressure is gone. The fluid level is good (although it has a black tinge to it. Maybe oil from when my car spewed it everywhere?) I bled all 4 corners and am still having the issue. The level doesn't change so I don't think its a leak. I have double and triple checked the vacuum line going to the master cylinder, the one way valve is allowing vacuum but not allowing boost to enter...all the connections are tight. I'm at a loss. I have a spare master cylinder that I can try...perhaps it's the seals in the master cylinder due to possible oil contamination? if this is the case what other seals should I worry about? I have 4 spare calipers that I can transfer over if I need to...what about everything with the ABS lines? my ABS doesn't work anyway so I have thought about getting brake lines from a non ABS car to replace these and remove some clutter. Any help is appreciated as always! Thanks guys!