Back in the dark ages when I learned my trade at my father's shop, most starters and generators were rebuilt "in-house"- - - -right down to changing bushings, field coils, etc. Armatures got growler tested, commutators lathe turned, and checked for shorts, grounds, etc. We also did a limited amount of regulator repair, particularly on the 6-coil heavy duty Delco-Remy units a trucking company sent us for rebuilding and recalibration on a 6 month cycle. The generator and regulator combo was assigned a unique ID number, and they were swapped out on a time or mileage basis, depending on the kind of service the truck was used for, long haul or local. The company claimed its "on road" charging system failures dropped by over 90% after going to that maintenance routine.
Jerry
