Most steering systems will have a pressure relief valve that could be stuck open. This would allow the cylinder to move when not connected to the system. Che k the block the two lines goes to and remove any plug to see if a valve is inside. You should also have a pressure relief valve in the orbital. Plug on bottom. You can also put a t fitting in where the line connects to cylinder. Use a pressure gage that reaches 3000 psi. Turn orbital far left then right, should see between 1500 and 1800 pressure. Good Luck