Brake master cylinder question
 

Hey wondering if someone can answer some questions. Brakes went soft of my ranger couple weeks ago and I had a explorer rearend to swap in. So I swaped in the explorer 8.8 and went to bleed the brakes and no pressure or fluid to the rear. So I bleed the master and very weak/ no pressure to the rear from the master. So I am assuming I have a bad master, but wondering if I should replace it with an explorer one since I have an explorer rear with disks? I search and couldn't find anything about running a explorer master in a ranger. Also read about a proportianal/ abs valve that might need to be changed when running disks? Any help would be awesome.