an 11MM box end wrench was used for the fan bolts. I found it easier to do this while the belt was still on.
I like the box end because the chances of it slipping are removed.
The fan itself as a spot where the blades are spaced further apart. You can spin the fan so that the gap is at the bolt you need to unscrew. It makes it easier.

Owner caption January 2010 · Photo 10 of 19