Originally Posted by Hot Wheels
I had the same problem. You can do two things: First is to take them apart, clean, and re-lube them. Don't do this unless you're a locksmith. Second, just take a spray can lube and squirt some in there. Do not use WD40, it will only make things worse for you. I recommend a product called Tri-Flow. It's a teflon based spray lubricant. It works wonders and can be found at most hardware stores.
WD49 is NOT your friend in the this application, Teflon is. I lubed my locks up but my drivers side still requires me to jiggle the key and play with it a bit in order to unlock it.
What doesn't help matters is if you've had to use the "Ranger" method to unlock your door in the past. I've done it a number of times, and it doesn't take much to bend the lock arms.
....and we'll leave it at that.