Who has Dr. Diff 8 3/4 rear discs?

Did you have a problem bleeding them?

I have his stage 1 rear disc kit with the mustang calipers, his 15/16 MC and his 73+ A body front discs on my 70 Dart with a drum distribution valve.

When the car is jacked up in the rear, idling in gear, I cannot get the rear wheels to stop when I push on the brake pedal. The wheels will slow, but won't stop.

I have bled them all along with the master, but I am out of ideas. I don't have parking brake cables, but did actuate the lever about 2 dozen times before bleeding. I haven't tried holding the lever (applying the parking brake) while bleeding, yet. I am getting fluid to the rear and can NOT turn the wheels by hand, if either brake or park brake is applied.

When the car is in the ground, it will stop if the car is idling in drive, but haven't tried it at any kind if speed.

Any thoughts?