On the way home from work the other day my rear brake started grabbing which I noticed in between gears while shifting. Checked brake fluid and it was topped off. The next morning I had no rear brake until it was almost floored. I tried bleeding it with a miti-vac and can't even get fluid out. The pedal had no resistance. Could it be a master cylinder bypass issue? There is no leak. Bike is a 1996 Ultra Classic. Dead in the water. Anyone have a clue?