Scott
Started on passenger seat: refer attached picture threaded rod goes through the pedestal glued to floor, under floor the rod is screwed into 8mm*50mm threaded rod joiners
If threaded rod fails, I would assume this would happen at the top of the pedestal due to pressure/movement of seat base, in which case may need to go looking for the end to get hold of it to screw out, or alternative drill out the top of the pedestal to get on to rod
finished seat to follow