International 584

[pontiacman]

I have a recently acquired 584, and am having a tough time with the 3 pt. It did not have lift arms on it when I traded for it, so I found some salvage pieces and put the 3pt back on. I hooked up the PHD and it is either all up or all down, depending on the position of the draft control. (light the PHD raises fully up, Heavy it drops immediately.) If set on heavy draft, I can lift the PHD with the position lever, but it will fall immediately when the lever is released. the only way to try hold a steady position is to make VERY slight adjustments on the draft control.
Any advice is greatly appreciated.
Thanks,
Scott