I've had good luck by heating it, but not even close to red hot. When you get it warmed up good spray it with some penetrating oil, you need to be careful because some sprays will ignite and start on fire for a second or two. After it cools some hit the pitman arm on the sides a few times. Then do it a couple more times. I've had good luck with this technique with things that are rusted and won't come loose. I've used this on brake lines with great success also.
Good Luck
Don
