In my experience, when the steering wheel doesn't return to center, that tells me the ball joints or front axle u-joints are starting to seize. The factory stuff is non greaseable so when ever they have to be replaced, I recommend buying greaseable ones so they can be maintained properly. Also, if you have to replace one joint (whether it's a u-joint or ball joints), I also recommend replacing all of them as once you have it apart it's not much more to do both as it is apart anyway. So you save on labor and expensive seals that you can't reuse.
The Hauler - '05 F-350 4x4 CC Dually 6.0 Powerstroke
The Project - '90 Ford Bronco 4x4
The wife's - '11 Ford Escape
For every minute you are away from work...you can add two minutes to your life!