I have an ISEKI SA 207 here and the three point hitch will not pick up a load. The bucket raises just fine but the 3ph will not. If I put the lever in the up position and get off the tractor and pull it up by hand, it will hold it there, and I can put my body weight on it and it will hold. I read that it could possibly be the valve that controls it. The speed is up but I have no idea where to go from here. Any help would be greatly appreciated, Thank you.