In Reply to: Golden Jubilee hydraulics posted by Gary A Ramus on January 07, 2020 at 18:50:29:
Don't guess. The leak test is easy to do and takes about 30 minutes and costs nothing but your time. When the lift won't hold in the UP position, it is most likely the cylinder and piston are worn and thus leaking oil down. A new safety relief valve won't fix that. If oil is a murky brown or whitish color, it is contaminated with water, but not the cause of your leaking. The job requires removal of the top cover and isn't difficult, just time consuming. Get a buddy to help. A new cylinder and piston are in order. The OEM 9N,2N, 8N, and NAA(JUB) all used the cylinder with the three steel rings with a leather wiper until Ford released the newer NAA-530 piston using a rubber O-RING instead of the rings and leather wiper. If you have an original 3-ring piston still, chances are the cylinder walls have become all gouged and scarred and thus the main root cause of the leak. I advise new parts -don't try to hone or rebore cylinder -it's a waste of time. Pulling the top cover is a job you don't want to do twice so do the job right the first time. Worse case would be to pull and rebuild the pump. Drain old oil, replace with new fresh.