After taking the old belt off my 1927 Model T, I found the fan blade has a small wobble in the shaft. Is this normal or should I replace the shaft and bushing.
Wobble is not normal. Check the shaft to be sure that it is tight in the arm. If it is tight, then the bushings are likely worn. The shaft may or may not be OK, you micrometer will tell you.
Good luck with your project. Bill
A very small wobble is OK. Be sure to put heavy oil or grease in the bushing. this can be done by removing a screw on the hub. Sometimes someone has installed a grease fitting in that location.
Another thing which is sometimes done is to install ball bearings in the hub. In the case of ball bearings, it should not have a wobble and should spin freely and smoothly.