Karl is right on the cause of your problem. The linkage that controls the traction booster valve is probably frozen from not being used. To get the lift arms to work, push both the traction booster and position control levers all the way ahead, use a 3/16" allen wrench to remove the cover at the rear of the valve and tap the valve spool into the valve body. Just be careful and don't get caught in the lift arm or the blade when it comes down. If you need the traction boost or position control, then you will have to free the linkage with penetrating oil or take the linkage apart if the penetrating oil doesn't work. If you don't need these features, just leave the control levers ahead and the lift will work. I hope that this helps.