Help needed - Proportioning control valve not bleeding

I need some wisdom and insight from you guys.

I recently acquire an ST1300 and decided to freshen up the fluids. I changed the coolant, clutch fluid, and front master cylinder.
I removed the left front caliper, shimmed it, and hung it to ~15 deg.
With my vacuum system at 20, I opened the proportioning control valve and nothing came out.
I read it may take a 1/2 turn or so before fluid came out. I had it backed out many full turns and still nothing.

What the heck is going on? Why won't it bleed? I don't want to go onto the other valves, but I don't know what to do about this one.

The secondary MC seems to move freely.

Please advise.
thanks
-gary

Pull 20 mg of vacuum, open the bleeder as much as you can, pump the rear brake pedal to help it along.

Uh, you do have the proportional control valve located? Dumb question but I had to ask.

Resolved.


There must have been some nasty ooze in the fluid causing some serious resistance as I was leaning on the rear pedal pretty hard with nothing coming out. I went ahead and bled a few other valves and came back to the PCV, still no luck. It wasn't until I bled the last valve on the rear and then tried the PCV again. SUCCESS! Just a 1/2 turn and pushed on the rear pedal.


I then went back and re-bled the valves that are after the PCV.