Here is a good one many may not know. But on the old reduction gear starters when I would rebuild them Ma put a washer on end of the armature where the brushes go with 4 bent legs on it. It worked great when assembling the starter as the washer would hold the 4 brushes in place so you could slip the armature right in and the brushes would fall in place against the armature when it pushed the washer out. It really made it much easier when assembling it. Ron