I have a 1999 F-150. A couple of months ago I started having trouble opening the drivers side door, it has gotten to where I had to yank it pretty hard. I've attached a couple of pictures of the door latch and ring. Notice that the wear is opposite of how it would be if the door was out of alignment somehow. The parts would be worn on the top metal piece, because that end of the door would have dropped down, but these are worn on the bottom. the truck was never hit, and I've never had a problem with it, but this just came out of the blue one day. Any ideas how hard this might be to replace myself, and a part number. I guess it's not called a "door latch" because I can't find it anywhere on the internet....

I appreciate any help you can give me...

Randy