One good safe way when knocking/pulling out ball joint tapers is to loosen the nut, but leave it on a few threads. That way if you missed something important, it can only move a quarter inch or so. I had amazing luck last week in removing all 4 upper and lower joints by preloading them a bit, loosening the nuts, and hitting the side of the arm with a brass hammer - just like Ed China on Wheeler Dealers does so effortlessly. First time it ever really worked for me.

DG