Tractor Repair: ford 3000 hydraulic lift problem, ford 3000 tractor, emery cloth

Question

I have a 72 Ford 3000 tractor in Louisiana that the hydraulics do not lift up. I've changed the fluid and put new filters on hydrualic suction and spillback and remove the pump which seems to check out OK. When the pump is turned on with tubing off you get good flow out. This problem started with the arms moving up slowly . Then it progressed to the point that you had to let the tractor run for significant timeframe before the hydraulics would work. It's progesssed to no movement at all. this is the same problem danny had as I read on this web sight. We also veryfied good oil flow to the top plate and oil is being pumped with the pump, but with the inspection plate open we can feel no movement of the piston to move the lift arms. Is there a check valve that could be stuck open not letting the oil get to the piston that pushes the hydraulic arms?

Answer
Hello,
  Sounds like you have done a thorough job of verifying that the pump is pumping oil to the hitch valve, but the hitch valve is not working.
  It would not be a check valve sticking, but an unloading spool or drop poppet in the hitch control valve that is sticking.  The lift cover will have to be removed to access the hitch valve.  All the spools should be checked for free movement, and the linkages checked for wear or broken parts.  If there are spools that are binding, they can be carefully polished with fine emery cloth and cleaned until they move easily.

                   Arnie