I have the cable back on. Do you know the adjustment procedure? When I tigthen the cable even a little bit, the caliper clamps the brakes down and the hub stops moving. I can free it up by lightly pushing the spring portion of the caliper back, but as soon as I start tightening again, the brakes immediately lock up again. I'm nowhere near where the nut was originally seated before all this.
When I pull the hand brake up then drop it down, the rear caliper locks but doesn't release. Backing the nut off doesn't release it either. It seems the only way to release it is to lightly manually push the spring section of the caliper back with a pry bar. Just a few 1/4 inch turns (with the lever down) and the caliper locks back up again.
I also have just that one rear wheel off the ground if that makes a difference since it seems there's a cable going to each rear caliper.