The later ones were shorter as they went with a dished steering wheel. I think the 57 is the same as the 58-9. Someone pop in & correct me if i'm wrong. They are easy to rebuild. The lower bushing is one part that wears & even the slightest looseness cwill cause a lot of play. The worm brgs are next. The ball nut & gears generally are OK unless someone left it a long time without grease. It is not nessesary to disasemble the ball nut as long as it turns smooth.
