some purepowers have two belts and others have one but procedure is the same.disconnect from mains,pull of height control dial,remove two star/posidrive screws from rear of casing,swing casing forward and remove. pullout brush roller,fit belt to silver motor pulley, insert brush roller through belt and align belt on to roller belt recess.pull roller/belt forward and push down into slots in casing,turn roller to align belt.refit casing taking care to ensure slots on front of casing fit into slots on body.now drop casing into position and refit screws and push height control dial into position.
jim mullin, January 2007