The locking system you have in your truck is known as the Ford 10 cut system. It sounds like your ignition cylender has a very common problem. I see this about once a week. The part of the cylender you insert your key through, the "ears", is actually a cap that is crimped on the lock core. The only thing keeping it from spinning independently of the core, other than the crimp, are three small **** about the diameter of a pencil lead. They protrude out of the core and into the cap. Those little guys get sheared off and the cap will now spin on the core. The ignition will actually still function normally if you line up the cap with the keyway. The most common cause of this type of failure is the steering wheel being locked and in a bind, as in pulling your self in and out of the vehicle by the steering wheel. The column lock is directly connected to the ignition lock. When the column lock is in a bind folks will invariably apply more torque to the ignition lock ears to get that "sticky" lock to turn. Guess what happens next. But, to make a long story longer, and back to the point. It's an easy fix. My advise to you is to go to your friendly neighborhood locksmith and purchase an "uncoded" lock cylender, hand them your key and code it to your key. Otherwise you'll have two keys to work your truck instead of one. Take an ice pick look on the bottom of the column directly under the ignition switch. You'll notice two holes, in one there's a screw that helps hold the column shroud on. Right next to it is a slightly smaller one, that's the access hole for the retainer. Put the key in the ignition and turn it to the "on" position. Put the ice pick into the hole in the shroud, you'll have to insert it about an inch or two. Your target is a small hole in the lock housing only about 5/32" in diameter. Your best bet is to carefully probe the lock housing while watching the ears on the lock. When you hit the retainer, you'll see the ears move slightly. Give it a firm push and remove the ice pick. Now, you should be able to remove the lock. To install the new one, put your key in and turn clockwise (if your looking at the ear end) while pushing in on the small retainer pin at the opposite end of the lock. It's about an 1/8" in diameter. When it's turned to the "on" position the pin will go in. Insert the new lock, turn it to the "off" position once you have it all of the way in. The retainer pin will move back out into it's hole in the housing, and your done! In the future, before you turn the ignition switch, turn the steering wheel to make sure there's no pressure on it. It may happen again even if your very carefull. They just aren't designed very well in that area. But maybe it will last a little longer. Just as a guage, I charge $30 for a 10 cut ignition, coded to your key. Some will be more, some will be less. Sorry about the long winded post, but I just love talking shop!
98 F-150 XLT 4X4 ORP Super Cab Short Bed, 4.6, Auto. Superchip, Gibson sing. cat-back, Airaid, 80/100w German head lamps. Needs one more door and a lot more power. I think I need to talk to Mr. Whipple.