Hey gang, just to start off, I did a Solid axle swap on a 1998 Durango using a 1979 Front F150 axle (on a side note, nice to know it has some freak odd banjo bolt that is basically impossible to find), and a rear 1978 Ford 9". I also took it a further step and performed a disc brake conversion on the rear using front '88 Lincoln Mk VII Calipers and the rotors off the front of a 1978 Ford Bronco. Anyways, we went to bleed the brakes yesterday, after going through an entire bottle of brake fluid and no response in the pedal I started to get itchy, so I got another bottle and commenced to gravity bleed the system to see if that would solve anything. The best I could get it is to where when the truck is off I can pump the pedal to where it becomes stiff. However when the truck is on no matter how much is pumped the pedal resides to the floor. I did notice however, that at the very bottom the brakes engage very slightly, enough to stop from a roll but damn sure nowhere near where it should be. Anybody have any horror stories they've experienced to point me in the right direction? I've came up with a few logics that I'll list and see if anyone can bite on this, please help, its hard enough looking at a Durango on 39's everyday lol.

A. I used front calipers on the rear, bad idea?
B. I did not install a proportioning valve, and the brakes that came on the truck originally were Drum rear
C. Given the pedal engages when pushed all the way to the floor, could it need a bigger/stronger M/C?
D. Is it possible that given the brakes had trained over the transformation a good bit, that I just need to keep bleeding the damn thing religiously even tho I'm already almost through my 2nd container of brake fluid?

Someone please help.