I need Hydraulic Help Again with my Ford 1920.

[Atvjoe]

Hi to all. I need help again. On my Ford 1920. I was using my box blade for about 2 hours and it started to hop gently and then the position Control lever started to lower itself and feel like it had like no drag like before. Then around the 2nd hour in use it barely wanted to lift the box blade. Info you need to know, I replaced the hydraulic Lift Cylinder seal about 10 hours ago on this machine and replaced all my hydraulic fluid and filter because my fluid was contaminated with water and slime. It’s one of my other post here.(it was bad). Does anyone have any ideas before I take apart the side cover of where the Hydraulic Control Valve is at. I’m thinking some o-rings are damaged or something got stuck like the plunger because my tractor was neglected by previous owner. There is no feeling to the lever. Let me know what you guys think, thanks again.