brake help needed

I replaced my master cyl but I still have no pressure at the pedal. The rear bleed good but once I got to the front I could get little to nothing to come through. there are no leaks anywhere. once the rears were done the pedal would stop hard about 3 inches from the floor and the rear does seem to be grabbing some, but no matter how much I try to bleed the front I get no more than a drip or 2 of fluid and no pressure at the pedal. I have done brakes plenty of times but never had this happen. I am wondering if there could be a problem in the block the lines from the master go to (I assume this is some sort of pressure valve) but I am at a loss. Thanks for the help.
Matt