5oz hammer and start smashing it like you mean it. Not one of those hammers for putting nails into wood. If you don't have new bolts put the nut on the end so you can prevent mushrooming of the bolt and damaging the threads. You'll be hitting the nut instead.
If I'm correct the bolts have some splines on them that jam into the knuckle so they don't spin/move. You need to just give her some loving and she'll come right out.