If it's the same as the 12/32 I have, after removing the nut on top of the pulley you need to unscrew the pulley off the shaft (same thread as the nut). It took me ages to work out the pulley was screwed on as I assumed it would be some sort of keyed fit like most other pulleys.
Once the pulley is off, the shaft/bottom plate assy should fall out (unless it's really tight in the bearings in which case it might need a tap out).
