Yes, propably the Trakball wasn't designed to live 30+ years
I cleaned the stucked bearing with some isopropanol alcohol then i put some wd40 on it to get it moving again and the add some finemechanical oil.
I also put some wd40 on the rusty parts on the shafts to clean them but that was't the best idear. Even after removing the rest of the wd40 with som elektronic component cleaner the cueball has a bit of a wd40 smell. I have to clean it again.
I also thought on put some shrinking tube on the shaft but i think it would have a bad effekt on the movement.
CNC will be a great option, i work for a company with a modern CNC machine. I will ask the operator if he could help me out in his freetime.
Probably the bearings are standart parts, i will ask a mechanikal engineer if he has a clou.
Today i played missile command on my vcs to test the joystick mode. Its real fun!
I recorded my progress as a video maybe i put it on YouTube help other cx80 owners.
Thanks for your posts, i will post my results if i could get some replacement.