We have heated our delivery truck straight axles at work bright red and beat the king pins out with a sledge hammer with full over the head swings, sometimes it just takes as much force as you can apply! Try heating them up till the grease and oil burn off, let cool, give it another heat/ cool cycle, then on the third try, beat the crap out of it. The trick is to not mushroom out the top so you drive them through the hole, be it a bolt or pin. I have had decent luck welding on the heads of stuck bolts, nothing fancy, just a big old glob of weld, the heat migrates up the shaft releasing them from the rust. Keeps from heating the surrounding metal.
Joe
