MCPV-1 - no rear brakes

I've been trying to get my rear brakes working with an MCPV-1 on my project but have been unsuccessful. I've bench bled the MC until its clear several times but once installed on the car I can't get any rear brake pressure. I've disconnected the front temporarily and I can get flow out of the rear but when I close the bleeders I don't have any pedal. I hook up the front and I have great brakes up front but still no pressure to the rear. The inner/outer adjustment screws are all the way out CCW (although I've tried several positions though with the same result). I've even pushed fluid from the wheels to the MC with a phoenix injector.

Anyway, anyone have any advice?? I'm thoroughly frustrated at this point.

Thanks