I'm now having a problem getting my brakes to hold pressure... All new stainless steel lines, rubber lines, calipers, junction block, on my 2nd new master cylinder, wheel cylinders and prop valve.. No apparent leaks, I'm at a stand still.. I noticed mopar discontiued their dual master cylinder for my dart which is pretty much the same one they use on a 94 Dakota so I purchased that one.. Do you have any suggestions for it not holding pedal? I realize it could be air in lines but I blead all lines 3 times for both master cylinders and same result.. I converted disc brakes off a 74 duster on the front, matching 74 duster 8 1/4 rear with drums all new. My brother and I have never had a problem like this.. Maybe you have some advice.