I have a jubilee. If I knew then what I know now, I would have purchased a newer ford with live PTO and power steering. The jubilee has more power than it's sister the 8n.
I had to rebuild my hyd pump. It's a piston pump. CHN wanted $2800 for a new pump. NO THANK YOU.
You have no way of knowing if the hyd pump gear is bad or the gear inside the engine.
I do my own repairs. I personally would stay from the old stuff that's not working as it should.
Buy new goodyear rubber for an old tractor and you will have more in it than you can sell it for.