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...
Bought this used when it was colder out. After it warmed up, the 3 pt (w/ box scraper/scarifier on it) would raise a little once or twice, never to full height, then wouldn't respond at all. Obviously something related to viscosity, and I'm assuming leakage around a valve or the piston rings...