bearing puller, heat and maybe oil?
if it sticks out with the shaft, you can basically make a reinforcement by drilling out a wood circle with a hole saw, drilling a hole in the middle, cutting it in half, assembling it under the fan, screwing it together, then using the bearing puller on that.
I had this problem on a tile saw, I ended up hamming the fuck out of it and just replacing the fucked up bearings, they were kinda old anyway. they are pretty cheap and it will help things run smooth..