zetor330 tractor

help help i need help please, i have a 1964 zetor 330 tractor, the hydrolic lifting gear at the back doesnt work,ive taken the top off the gearbox and everything seems to be ok,the hydrolic piston and seals seem ok and also the valves,if i engage the pto and set engine at high revs it will lift up but not if any weight on it, i would be greatfull for any help,thank you,craig

I am new here and ant no expert, But if i try to help perhaps someone will help me. I have done a lot of electrical and starter and alternator and generator work.

My long is kinda distant cousin.
But there are some basics.
1st be sure the pump is producing, fluid level, filter or strainer and break the line to see the flow and volume going to the lift section.
Even a 5 gpm pump will fill a 5 gal bucket fast or drain the system.
2nd check all the caps, if any there can be valve or pistons under them they must be clean and un gunked and move. pulling them wile running to see if and how fast they flow.
( last time i worked on my long nothing happened but under one cap was some linkage that was stuck from setting one bump and it moved and the lift came up )
You may need to pull the whole valve assembly to clean and be sure its un blocked and the mechanical parts are working.
3rd or perhaps first, pull the pressure relief valve and clean be sure its not gunked up and not closing properly. And blowing off your pressure before it builds.
A good service manual may show you where you can tap in a pressure gauge and whats doing what where?

My tractor expert died a couple years ago or i would ask him, I would bet he had worked on one.