[suicideneil]

The rear end cap is screwed in place with 3 tiny screws ( M1.5?, small at any rate ), are they missing?

I would take out the rotor and check both bearings are good, and that the little brass spacers / shims aren't missing either. If the magnet has come loose on the shaft then you should see a 'tide mark' where it used to be further back onto the shaft as such.

I would suggest to tap out the shaft if it's stuck, just use a small 'hammer' and a flat head screwdriver or something similar- just be 100% certain there is no pin or anything holding it in ( the bearing may be a bit warped from front to back so it's mashed against the shaft ).