1988 Chrysler New Yorker Brake Bleeding

I replace front brake flex lines because they were leaking. After replacing them I can't get any pedal. I have tried several different ways to bleed them and always falling back to the normal rr lr fr fl. Still no pedal. I have checked the booster and even replace the master cyl. and still cannont get it to take. I also can open one of the lines at the proportional valve and can get the light to come on so I believe that the proportional valve is working. I have bleed the master cyl. Matter of fact, I have replace it 3 times with new ones thinking that I was getting bad ones. (Good thing I have a friend at AutoZone). I just can't figure out what I am doing wrong.???