Tractor Repair: 9-N Ford, ferguson 35, draft control

Question
I have a 1939 9 N tractor it runs good, but I am annoyed by the lift. It is either up or down. I grew up with a Ferguson 35 and it had draft control. Is there anyway I can adapt a 9 N to have draft control? Thank you for your time in answering me.   Kevin.

Answer
Hello,

  A 9N does have draft control.  The large spring where the center link attaches to the tractor is what controls it.  The harder the implement pulls, the more it compresses the spring and moves the linkage to make the hitch raise slightly.  If you can't control the height of the hitch, there is a problem with the control linkage or the hitch valve.  Possibly worn out or bent linkage or sticking spool in the hitch valve.