you will need to remove the front of the machine. un-clip the wire loop around the rubber seal.un tighten the 30MM nut at the rear. unscrew the big wheel with the belt on it. (anticlock wise. you will need a steel cup 53mm inside dia to pull the bearing into with a threaded bolt and nut. pull the new bearing in with the same cup. you could make this cup with a piece of steel tube and steel cap with a 12MM hole in it.
alexander cutmore, January 2007