Draft and position control linkage

[foster4]

I've got a MF 30b on which the 3 pt won't raise, but it will move a little on occasion. I opened the right side cover and w/ engine off, if I move the position and draft levers, I see little or no movement at the vertical lever that activates the pump control valve lever. The last time I did it, I was able to get a little movement when putting the draft control all the way up, but that was it.
Can anyone tell me what I should be seeing, such as how much movement there should be at the vertical lever when I move the draft/position levers? Or, does anyone know if there is a way, through the porthole, to free the control linkage if it's binding?
Thanks.