The edges of the impeller blades look worn indicating liquid impingment. It looks like the metal was worn off the blades and deposited on the outer ring of the impeller. Were the impeller and labyrinth seal fused together on the impeller nose? They look fairly clean. What was actually locking it up, bearings or fused metal? The nut looks factory. If you need an Imp, seals, bearings, (maybe motor overhaul)etc on a 30 yr old machine it may be time to move up to something newer
Camera comes in handy, huh?