Rebuilding hyd cyl.
I would recommend taking it to a hyd shop and have them measure and fix the cyl and then test it.
Most people will not even know what to measure and how to measure.
You have to know things like bore diameter, piston diameter, land width, land depth, seal composition.
Need to check bore for scoring, any bulging, piston nut strippedand loose, rod bent, rod nicks, etc.
You might go to the hardware and find something close, and it might even work for a while, and then , and then, oops, to late, there she goes Fred.
Anyway, you can try it yourself if you want to. Some are easy and some are hard.