Ford 4000 Questions

Have been doing some work with my Dad's 1971 Ford 4000 diesel and have some questions/concerns. Not sure what to expect on some of these items as this is the first tractor like this we have had. I have been lightly working an ATV trail with a 5 shank 3 pt chisel plow and also doing some brush hogging with a 5' unit.

The 3 pt lift is funky. Sometimes it will lift and sometimes it won't. If I hit a certain spot on the lift quadrant it will lift all the way up, otherwise if just lifts a little and I have to mess with the lever to get the brush hog all the way lifted.

I only have draft control and the chisel plow and brush hog are constantly adjusting height behind me. Wanted to switch the 3 pt to position control but the lever for switching between draft control and position control won't switch and I don't want to force it. I can move it up slightly but it feels like it hits something solid.

The dial for hydraulic flow control has no resistance and if you turn it out it actually unscrews right out of the block it is in. Feels like it is disconnected from something inside as it turns very freely.

Help an Oliver guy get this handy little Ford fixed up!

The control lever is hard to move and takes a fair amount of force, One of mine has been cut shorter and I have to use vice grips to get it to move. The internal linkage is like a cam action that takes considerable force on the lever to shift from one position to the other. It seems to move easier with the lift arms down.
Turn the flow control all the way in to max flow and leave it there.