You MIGHT find a Hydraulic Shop that can/will rebuild them. I doubt that you can do it as most of the jack cylinders are welded together and have to be cut apart in a certain way, rebuilt and then realigned and welded back together. If you have a lathe and can fabricate up a jig and trust your welding skills, go for it.
1995 Gulf Stream 34' Scenic Cruiser Diesel Pusher 8344WFD, 1984 Shasta TT 28',
2019 Jeep Cherokee TrailHawk Elite,
Road Master Sterling All-Terrain Tow Bar,
Air Force One Brake System