master cylinder

["Abrusci, Mike (NM75)" <mike.abrusci@domain.elided>]

I have done rear disc brakes and am having problems with the feel of the
pedal. I have bled the brakes (2 quarts), adjusted the rear e-brake, all new
calipers, pads and rotors, per Warn I pulled the spring and plunger out of
the back of the master cylinder. The pedal feels like it goes down too far.
It seems to stop ok but feels a little spongy. The pedal does not go down
with continues pressure like a bad master cylinder. 

Could this still be air in the line?
Does disc brakes need positive pressure out of the master cylinder?
Do I need a disc - disc master cylinder?
Do Internationals usually have nice hard pedals?

Thanks, Mike