Bleeding manual brakes with prop valve

I am bleeding the manual brakes (first time) on the '66 Coronet, rear drums and SSBC-kit manual discs front. All new M/C, lines and all hardware.

I bench bled the M/C- bubbles gone and fluid clear. I gravity bled the front brakes, bubbles gone, clear fluid now and closed the bleeders.

But I cant seem to get the rear brakes to start gravity bleeding. I have the SSBC supplied proportional valve (labeled "increase"/ "decrease") for the rear brakes mounted about a foot and a half or so from the M/C port.

I set the rear prop. valve to max "increase" setting. After two hours with both rear bleeders open, I still haven't seen the reservoir level drop at all.

Is there anything special I have to do to get the gravity bleed started because of that inline prop valve, and is the max increase setting correct?

Any possibility that the valve is in there backwards and the proportioning is shut down completely? If not crack the line into it & see if it has flow when someone presses the pedal

Pump the brake pedal until you get some fluid flowing.

Thanks guys!

I disconnected the OUT line at the prop valve, and no fluid.

I set the prop valve to about 50% of range, and a couple of pumps of the pedal later the problem was gone.

I just expected the line to start gravity bleed without pushing the fluid with the pedal. Thanks again.