Tractor Repair: Ford 9N tractor, ford 9n tractor, piston seal

Question
the three point won't stay level just keeps digging in then raises up and then digs in again when I hold the control lever at the same place?

Answer
Hello,

  Raise the hitch all the way up and shut off the tractor.  If the hitch settles down in a short time, the lift piston seal or hitch valve is leaking.  If it is able to hold the implement up, the problem is in the draft linkage.  Either way, the lift cover will have to be removed from the top of the rear end housing to fix it.  Then everything can be inspected at the same time.  Also, check the spring where the center link attaches to the tractor, to see if it's too loose or broken.

                           Arnie