Well, I pulled the rear wheels off and inspected everything against a detailed photo. The lower retract spring on the driver's side had either not been properly attached or had somehow come loose. I put a hardware kit in both drums and all the springs I pulled off were noticeably wimpier than the new ones, clunk eliminated.

On to bleeding. Re-bled the master in place using the brake pedal. No fluid drop. Bled the RR with the mighty vac and sealed it. Attached mighty vac to the LR and could get no fluid. left the catch can hooked up and used the pedal, appeared to work. Went back to the RR, opened the bleeder, attached the catch can and gave it a couple of pumps, repeat once again for the LR. On to the front, the pedal goes to the floor both sides, properly bled.

So, the pedal would only go halfway down on the rears, and with the whole system sealed, the pedal only goes halfway down. I am befuddled. I think it either has to be a partial blockage in the rear channel or that 2yr only combo valve that I had replaced some of the seals in years ago. At any rate the situation is a bit improved, but more work required.

Any ideas here regarding the valve/blockage?