The front crank seal is a one piece seal. You must remove the balancer in order to replace it. I had to remove my electric fan as well, but I have a larger blower pulley. I just pulled the fan, the overflow bottle and mount, removed the belt, yanked the crank pulley, and then removed the balancer. You can remove the seal with a screwdriver and pliers. A very large socket or piece of pipe makes installing the new seal very simple.
The Ford part number for the seal is: E6DZ-6700-A.