I'am guessing you are trying to get the center bolt from the crank shaft out. I'am also guess you don't have access to air tools for this would be the easiest way to remove it. If you have a flywheel wrench you can have and assistant hold the flywheel while you remove the bolt. Also if the car is a stick you can leave the car in gear and this will also prevent the motor from spinning while removing the bolt. However if you are referring to the fan bolts leave the fan belt in place to pervent the fan from spinning while removing the bolts
Hope this helps. BYM ?