I've been helping my dad work on his 73 or 74 jacobsen hydro drive tube frame/open side tractor - it's either a 12hp or 14 hp. We've had the lift cylinder re-built and also replaced the busted-up cooling fan. The lift cylinder control valve is leaking and I was wondering if it's possible to rebuild the valve. I've rebuilt log splitter valves and a JD power steering column - so I have just enough knowledge to be dangerous. Can these lift cylinder control valves be rebuilt? If so, do you get a rebuild kit from New Holland or the original valve manufacturer? For instance, with JD, the power steering rebuild kit came directly from a Parker-Hannifin dealer.