I just wanted to post this hopeing it might help someone. I was trying to install the 2-3" lift keys on my '02 supercrew. Just struggled through the body lift and was hopeing the keys would be easy. Not so lucky....Mine were rusted solid! I tried soaking with penetrating oil, tried a long pipe around the front of the A-arms with a 10lb. sledge to loosen the torsion bars, tried a punch and socket extension from the rear, nothing was working. I beat the keys with a 3lb hammer on the side thinking it might flex enough, like a tie rod end, to break its hold and work loose. I tried a large prybar in the crossmember. Finally, I got my Mapp gas (which I had already tried once) and sat it on the floor below the key and let it heat up for a few minutes. Then, I got the air chisel, with a dull chisel bit and started hammering with it in the hole where the adjuster block sits, on the far end of the key. I would air hammer there, then come back to each side of the key where it goes on the torsion bar and rotate back and forth. Finally busted them both loose! This worked really well when everything else I had tried wasn't getting it done. I was starting to wonder if I was going to get mine off. I then unbolted the crossmember, slid it back so the keys fell off and installed the new keys on the T-bars as I slid the crossmember on, one side at a time. There is enough play to do one side, then the other with no problems. Made a tough job easy! Hope this helps.

 

I know exactly what you are talking about, those keys can be a real bear to get off if you live in the rustbelt. I haven't dealt with any of the 97 and up Ford Trucks on this issue, but I have had several IFS GM trucks apart to install lifts or lift keys. I know they are very similar in design and not much fun to deal once they are "welded by nature" as I call it. On the trucks I was replacing the keys on I cut and split the keys to get them off. On the trucks I didn't have to replace them, I was luck enough to be able to break the torsion bar loose at the control arms.
Good handy little trick, thanks for the tip... Doncha just hate air tools?