Turn the valve all the way in and then out and split the difference to insure the Proportioning valve is opened.
On your deal with the after market rear disc brakes I would remove the rear calipers so I could hold them up as far as possible towards the sky to make sure all the air in the hoses and calipers where being forced into the top part of the calipers so it will be bled out when you bleed it the next time
I had to use this method on my airplane to get all the air out of those calipers
Air compresses fluids don't