2 brush generators with a fan

[cas3]

this question came up at the hamb, and i thought i was sharp enough to answer, but it only brings up more questions. so, to my understanding, only the 3 brush units from 32-36 have the double row tapered bearings, like a front wheel bearing for example, to control the fore and aft load from the fan. in 37 the shaft got bigger, and we know ford used the fan mount genny to 38/39 in cars, and even later in some truck applications. looking in the green book, it shows the same bearing number from 32 to forever. but that cant be right, as, again the shaft size gets bigger in 37. in an old post from Bruce Lancaster, he says you can get dizzy looking at the generator section in the green book. i can relate. so, the point is, the 37 and up use a ball bearing, yet some still have a fan, so the single ball bearing of a later 2 brush unit will take the load from a fan?