Down Pressure on a 3 point hitch

Or, do you have an IHC 2-point hitch with a conversion to 3pt with the slip in arms?

My IHC 300 would be like that, a 2pt system with down pressure. It has a vertical shaft in back that is used to lift & lower the hitch, and this shaft has a pin in it. Pin in & it's down pressure, pin out and it's floating.

I'm not familiar with your model number....

--->Paul

Sounds to me like you have a double acting cylinder(s) but are only using a standard spool valve w/o a float position. Such an arrangement would provide up force with hydraulic pressure applied to both cyl ports simultaneously with the spool in the up position, float (or down) with both ports open to return in the down position or fixed (cyl locked in position) with the spool in neutral. If that is true, it should be relatively simple to replace your control valve with a spool that also has a fourth position that provides the float. That way the down position would be used to actually power down (down pressure), the up positon of the spool would power the cyl up, the neutral position would lock the cyl in position and the float position would permit the whole thing to float over varying gound. To me, this is the only way to fly and should be an easy changeout unless you are using some kind of OEM built-in control valve thingy. I don't know what your pump output is but normally powering both ports of a double acting cylinder at the same time results in a faster cylinder extension but with a significantly lower force than what the system is capable of giving. Re-plumbing through a four position spool (incl float) would slow down the action but also provide a greater lift force at the same time, in addition to providing down pressure.

Rod