I had the same problem a couple of weeks ago. I ended up calling a friend and had him come over and help me do a standard bleed. My right rear was the only one that gravity bled, and it still had some air in it I discovered when my helper was pumping the brake pedal.
------------------[*]'71 Cheyenne, 402BB[*]Winfield, KS[*]
http://barn9.freeservers.com