I ended up replacing that one bleeder valve screw. Didn't seem to make a difference, but it did seat in more firmly, like it should. The end result was the same: air in the system. So, my mechanic acquantence from church was in town, and he came over and looked at it. He bled the load leveler valve while I pumped the brakes. All the air's out now. I felt so stupid. I hadn't done that one because I was convinced there was a problem in the front left caliper (leaving the leveler for last). I still can't explain what I was experiencing, but now the air is out; so life is good again. <img src="/forums/images/graemlins/rolleyes.gif" alt="" />