Well I know it's been a while since I asked about this brake issue, but I finally got to working on it and here is what I got. Replaced booster, mc, checked all linkage, etc.. After replacing booster pedal doesn't stick down, but now I hardly have any brakes. New mastercylinder went on at the same time which was bench bled and bled brakes at all 4 corners. Problem is as you pump up brakes they intially go to floor then will get hard mostly to top, but after stopping for a few seconds and pumping again they go striaght to floor again. They are actually worse than before with the exception the pedal hasn't stuck down yet. I am thinking I still has air trapped somewhere but no matter how much we bleed them I can't get any air out, in fact I only got air out of the left rear and that was the first crack of the bleeder then no more. Any ideas will be very appreciated! Thanks moparts!