I replaced both rear calipers and now I'm having trouble bleeding. At first, I had a bad bleeder nipple on one of the ATE rebuilt cylinders. It had a burr on where it seats. When I discovered this, I was getting good pedal, but could make the bleeder not leak- so got a replacement bleeder.

I had my son come help and we did the "pump-hold-bleed" method.

Next day (today), I put on the new bleeder and try to bleed it out. No pedal- and nothing comes out of the bleeders!

Also, I put in DOT4 - should I only use DOT3?

Somehow, I seem to have messed up the master cylinder seals so now it doesn't work at all? I get no pedal.

I'm assuming this is the case- but I have been bleeding brakes this way for 40 years with no problems...