Out upstairs bathroom Broan Model 164A light/heater/fan was making too much noise when the fan was on. We purchased this unit in Jan 1978 for $35.
I ordered another motor #99080160 for $45 however it was identical except for the shaft diameter which was 0.249 inches instead of 0.222 inches of the original shaft. The motor did not come with the replacement fan.
Since there were so few options on purchasing this motor I modified the plastic wheel fan to accommodate this larger shaft size. This shaft has a flat edge to lock the fan onto the shaft in a securely. Don said to end up with a balanced wheel I would need to file out the notch on the fan and then drill it to a larger size. By doing it this way the new drilled hole would remain centered in the fan. I found my Dremmel tool easily ground this flat portion of the hole away. Then a larger hole was easy to drill into the plastic fan wheel and then the hole ended up measuring 0.235 inches.
I then pressed and glued this modified fan wheel onto the new motor shaft using JB-Weld. Now the noise is back to normal which was originally rated at 3.5 sones. Maybe this will be good for another 32 years?