rear end help

I have a 83 f100 that i put a 302 with a c6 in it and had the rear gears changed to a 3:55. The rear end is a 8.8 and i wanted to change the axel seals but i can't get the center pin out so i can pull the axels. The book says to just remove the retaining bolt and push the pin out then remove the clips e.t.c. but it isn't that easy, i've even used a 5/8 bolt trying to drive it out and it want move. can anyone tell me some other ways that might be helpful.

Thanks!!!!!!!!!!!