Bleeding brakes-1995 Transport

Afetr almost 12 years changed out the calipers. Tried to change hoses as quick as possible, filling master clyinder between sides. I don't think it ran dry. When completed frist gravilty bled system got a firm pedal about mid way, then started engine and pedal turned to mush and almost hit the floor. Pressure bled the calipers using the push the pedal, crack the bleeder screw, then close it at end of stoke. Got a leittle better, but still not as it was before hydraulics were opened. No ABS lights.
Now have bled rear circuit, and getting lots of air from right rear cylinder. Have bled over 2 liters of fluid and still have air spurting out. Tried bleeder scrws on master clyoner/ABS no air there/ Cracked all 4 brake lines at ABS, no air. is there something I am doing wrong? Pedal still almost hits the floor, although brakes seem to function OK, ie it stops!
Any advice appreciated, thank you
Jeff

Sorry, I don't have an answer but I thought I'd reply so as to bring this one to the top as I'm got pretty much the same problem. I replaced my front calipers & pads as I had dropped the front cradle to replace the engine & trans. When I did the reassembly, the bleeders were pretty rusty & broke off so I went ahead & replaced the front calipers & pads. Now, I've bleed the crap out of both the front & back & the pedal is acceptable but not any where as good as I'd expect it to be. Anybody have a suggestion ?

Just an update. I did re bleed the system got a little better. Then we ran into some wet and snowy roads, and I made the ABS work several times, made several panic stops. Gradually the pedal seems to be coming back to where it once was, but over time. I figure I have bled about 4 liters of fluid so far, and the air has stopped bubbling. I guess air got trapped somewhere and has worked it's way out.
Just as a note for future, it has been suggested to push and hold the brake pedal about half way down when working on the brakes. This closes the compensatiing port, preventing fluid from draining from the master cylinder. You will still lose some out of the line but at a very slow rate. Sounds like a good idea for future brake work to try prevent this hassle
Jeff