Can it not be rebuilt? The starter on my '46 died this spring while I was doing my annual compression checks. The spare rebuilt starter I had was from a '51 8BA, which fit and works great. I'm fortunate to have an old school starter/gen/alt shop in my area where I dropped it off. The fellow called me to tell me that the starter had been rebuilt several times, as the commutator had been turned past the minimum diameter, and the new brushes would go too deep in the brush holders and would not sit square to the comm, and the spring pressure would be too low to prevent the brushes from contacting the comm properly. The owner tried to find a new comm but the ones he could find didn't have the keyway and the hole at the end of the shaft for the bendix.
As a result, I hit a few swap meets and picked up two starters with original bendix drives. I took them to the shop, and he built two good starters form the original one I brought, and the two I got at the swap meets. I noted that the bendix gear retaining nut had dates stamped on it, that listed a bunch of years for which they would be compatible.
