Brake Bleeding w/ ABS, PowerBleeder - Air?

[bruce.g.cameron]

I've replaced rotors and pads all around, replaced 1 caliper and rebuilt the other 3 (which are still quite rusty on the exterior).

I cannot get the Passenger Rear to bleed properly. I get fluid at the other 3 lines, but at PR I get a mixture of air and fluid. At first I wondered if it was the old rusty bleed nipple, so I got speed bleeders all around, same issue.

I've tried bleeding with the powerbleeder as well as the 2 man.

Here are my hypotheses:

1) The bore the bleed nipple screws into is too wide. At 1/4 to 1/2 turn, the bleed screw has a little side to side play in it. Could this alone cause the air? If so, new caliper?

2) I blew the seals in the Master Cylinder somehow.


As an aside, I built the garden sprayer-style powerbleeder, using an old Benz cap. I can't get it to not leak fluid - I put a bunch of plumber's tape on the reservoir threads to minimize it, then stuff paper towels around. Others have a similar issue?

Thoughts ?

Thanks,
Bruce
70k 190D 1989