What kind of lube did you use? Too thick of grease can hold things up. Was the leather on the paddle in good shape? Sometimes by moving the vacuum hose, it can get cracked if it's brittle. I haven't messed with Model A vacuum wiper motors, but plenty on my '57 Ford. They probably aren't much different. I saw this on Snyder's website, may help.
https://www.snydersantiqueauto.com/content/Snyders/Product_PDFs/A-17500-K.pdf