Help ! 2000 GT

3 pieces of wood. 2 to space you above the crank snout and the other across the top of the first 2 to hit with a hammer.

I would bet ford has a special tool you could buy if you really want to do it the 'right' way.

OR....

On the 2.3, you can just get a 2" diameter pipe about 4" long to hammer the seal on with. I would imagine a similar tool would work well on the 4.6, and that you just have to match a pipe size to the 4.6's front seal diameter.