Brake bleeding and red brake light

[Orence1]

Red brake light came on when driving home from the body shop a few weeks ago on my 72. Found the master cylinder rear reservoir completely dry. Filled it up, started the engine and the light was out. Came back two days later and light came on again. Went ahead and bled the rear brakes today using a vacuum pump brake bleeder. I ran about 4 oz. through the left cylinder and about 8 oz through the right. Made sure the master cylinder did not go dry. Did not get a clear stream but directions indicate small bubbles caused by connections not being air tight can occur. That seemed to be the case. Red light still is on. I took a test drive around the block and I have a right rear brake that is locking up with moderate pedal pressure. Any suggestions before I let my mechanic loose on it?