8N's should lift approximately 700-800 lbs. First what is the condition of the oil, is it milky and full of water. A common problem with the old Fords that are left outside uncovered. Next take the round side cover off (the one without the and with the PTO lever), with the tractor running look inside to see if you see the oil swirling, KEEP YOUR HANDS OUT OF THERE with it running. If you see it swirling then it is likely the relief valve is stuck open, an easy fix the can be done thought the side cover. If you do not see the oil swirling (there will be some movement of the oil, just not excessive) then look to see if you have a lot of oil coming down from the top cover, that will indicate the seal on the lift piston is leaking. Again not a hard to do job, an hour to hour and a half depending on how many adult beverages you take breaks for.