Ford NAA lift problem

(quoted from post at 17:11:05 03/17/19) So Im working on my NAA lift. I went all through the top cover,replacing all gaskets , etc. I replaced the flat o ring on the side of the cylinder for the back pressure valve. While working on the lift I found that the safety valve(which screws into the back of the cylinder) spring was broken where it attaches to the safety valve and the 7/16 steel check ball was missing. I replaced the ball with a new one and was able to reuse the spring because not much of it was broken. Now my problem. When I put the lift cover back on the tractor and started the tractor up, the lift arms raised up all the way to the top by themselves and stayed there. The control lever has no effect at all. While the tractor is running I can force the lift arms down with my hands with considerable force and when I let go they return to the highest up position. I adjusted the turnbuckle linkage just to see if that made any difference, but it did not. The arms still came up by themselves and the control lever has no effect. These systems have safety valves and relief valves etc. It makes me wonder if one of those could be acting up. I hope this gives enough info to where someone may have the answer. Thanks for any help and advice.

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