Doug and all,
 
You should hold the typewheel with your fingers when removing the nut and washers that hold it.  Same when you replace the wheel.  If you break the post that holds the wheel its quite a chore to replace the post.
 
Trial and error to get it perfectly aligned.  I think there is a small procedure on the wiki site.  Many thanks to Jeff Albrecht  for setting up that site.
 
Best regards,
 
Wayne
KB1FDW