There are four main reasons why your steering wheel might lock up in the middle of you driving even though it's only supposed to do so when it's not in use. You could have an ignition lock or a power steering pump failure. You could also be making frequent sharp turns or you could be using the wrong key all this time.
After learning the cause of the lockup, you should act immediately to fix it so that it doesn't happen again during a critical moment, like when you're driving in the freeway or something. This can serve as a DIY guide in case you want to save money on the other sensible solution of letting your mechanic handle the rest.
Viable Fixes and Emergency Decision-Making
- Apply Power Steering Lubrication Oil: Before applying power steering lubrication oil to a steering wheel with a tendency to lock up, you should first check for air in the system. Maybe topping up the fuel level is enough and maybe it's not. From there, bleed the power steering system and flush out the liquid. Afterwards, put in a fresh supply of lube oil on it to make your steering wheel stop locking up so much.
- Avoid Routes with Sharp Turns or Slow Down During Such: Pay attention to where you're driving and slow down during sharp turns. Minimize having to do sharp turns in the first place to reduce your risk of a steering wheel lockup in the middle of driving. This also keeps the locking mechanism from being damaged in the first place because those sharp turns in and of themselves can do a number on it.
- Clean the Steering Wheel Column: If you're adept enough, remove the steering wheel on your car in order to access the attached steering column for cleaning out any grease, gunk, and dirt that's making your wheel lock up. It's usually connected by a big nut holding the wheel to the column, a splined shaft in the column, and a mating hub in the steering wheel.
- Repair the Power Steering Pump: You can follow the directions on a power steering pump repair kit or do it yourself. Locate the pump at the bottom of your engine bay, place paper on the floor to see where the leak is, tighten nuts on the pump, replace any cracked hoses, check the seals on the steering wheel, and bleed lines of any air. If symptoms persist, consult your mechanic.
- Replace the Ignition Switch System: To replace the ignition switch system, you should remove the steering column, detach the wiring, test the switch, install the new switch, and secure the switch by reinstalling everything in reverse order. Some cars are more difficult to deal with than others because of an installed anti-theft system. Let your mechanic handle it if it's too much for you to deal with.