Im pretty sure you dont want to take that thing apart, where would you get parts? Imes isnt going to sell you the guts of that spindle, only a replacement. There are companies that rebuild them though, if you find one let us know. Imagine isnt one of them. Its probably going to need a plane ticket to germany..
If the spindle is off means that it might need a technician to calibrate it with a dial indicator, unless you have admin rights to try and verify your zero point, not to mention there could be tests to verify its operating correctly.