What kind of fan is it? updraft, downdraft, squirrel cage? Do you have the tools needed? a bearing puller, a level, an amp tester that clamps on to the wiring? Are any lisences required in your jurisiction? Do you have any idea what kind of problems you are letting yourself in for?
I would not attempt to take most fans apart. Clean the nasty thing with a scraper and with your pressure washer as best as you can. I've got fans that I 've cleaned for several years, and still are not up to my standard. If this fan was not cleaned properly before, you may never get it to bare metal. Make sure the fan is not noisy and not out of balance.
If you really want to take it apart, go for T & M.
Douglas Hicks
GENERAL FIRE EQUIPMENT CO OF EASTERN OREGON, INC