Call David Ficken listed in the parts and service directory. I think he is the guy, he was very prompt with me 2 days ago and very upfront about what he can do realistically. Be warned the news might not be good. Hopefully 1933 wiper motors aren’t as rare as ’34-35.
On mine he told me that ’34-35 sedan motors were only used on Pierce and some Buick and has only seen 5 in his career. He doesn’t have good parts to rebuild them. It seems prewar zinc does it again, it swells and distorts the case slightly so the paddle can’t get a good seal.
I got mine to work briefly but not for long on a vacuum pump. I will be doing some experiments on mine in the coming week.
On my “36 Packard with the same wiper arm and slightly longer wiper blade they aren’t that effective when they do choose to make a couple of swipes, there doesn’t seem to be enough force to get a “clean sweep” even with fresh blades. Packard had a variable speed function that I joke means it goes from dead slow to stop. Meanwhile, Rainex is a pretty amazing product.