In dismantling the generator of my British car the other day, we were
faced with the usual problem of how to hold the pulley so that we could
get enough force on the fixing nut to remove it. After some
deliberation, ‘BING!’ on goes the light! We took the fan belt and put
it tightly around the pulley. We then put the fan belt in the vice. On
went the wrench and off came the nut.