Another brake bleeding issue

[chrismoore701]

So I think I know what I am doing. I was having trouble bench bleeding the master cylinder because the cheap plugs were sucking air. So I did it a couple times on the truck and got all the air out. Fronts bleed great. I can not get any pressure out of the back. So I checked my lines as people on here said to do. And traced it all the way back to my new master cylinder. Does not have pressure at the outlet. Tried to bench bleed it again on the truck and I had pressure at the connection at the master cylinder. Put everything back together no pressure at the rear. Am I missing something? 1979c10