Last night I worked on the door lock problem. I picked up some tools to remove the spring clip that holds the lock in the door handle. Its in a tight spot and you need something sharp to get it started. So, I get the lock out and disassemble it. Yep, some of the tumblers are worn out. The quick fix is to just remove the worn tumblers and leave the rest in. It makes the lock a bit more vulnerable (more keys will fit it), but I can't ever really see that being a problem.
Here are some pictures:
Here is the lock cylinder with the key in it. You can see all the tumblers are flush with the outside diameter of the lock cylinder. This allows the cylinder to turn in the housing. When the tumblers stick out, they are in grooves in the housing which prevent it from turning. As the tumblers wear against the key, they start sticking out.
Here one of the removed tumblers and its spring. There are still 5 or so tumblers in the lock to keep it secure.
Here is everything. The lock housing, the lock cylinder, and one of the two lock tumblers and springs I removed.
