Post edited now that a solution found. Read this and it turns your locks back like NEW!!

............

My key was getting a touch hard to put the door lock, so I put some graphite powder in there with a squeeze tube, which I do maybe once a year.

But when I was done ......the key didn't go in the whole way so I couldn't lock the door! It was out quite a bit, about 3/8" away from going in the whole way! I don't know if a chunk of graphite came out of the squeeze tube or if a bit of the plastic tip from the tube broke off in there, but I couldn't lock the door with the key.

I didn't want to use WD 40 because I knew it'd attract dirt, etc. So I tried some lithium spray in there, and WOW! What a difference!! Some black sludge came out, which was maybe a chunk of graphite causing the problem perhaps, but now it works like a total champ, better than new!

Try it! You'll LOVE it. I put it in all my door locks and they all work great now.

jeff 1991 300d, 200,300 miles.

Did the metal leaf that normally covers the tumbler slot fall off and get pushed inside?

__________________
'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
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As stated in the other thread, Lithium grease is just as bad as WD-40. It attracts dirt and dust and will gunk up the lock in short order. Only use dry lubricants in lock tumblers.

__________________
'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
http://badges.fuelly.com/images/sig-us/302601.png
http://i959.photobucket.com/albums/a...0/sideview.png

If they do get to apoint that they wont open the door then this is the way to go ..For older cars only

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+1

The reason this happens in the first place is dirt and wear, either on the key or the cylinder pins. Before you mess with the locks, try your key all around the car and replace the key if the problem follows the key.

I just did this for both my door and ignition cylinders. Now as smooth as can be. But it's not quite as simple as the photos. I did a photo writeup on ignition cylinders, and I'll do a photo writeup on door locks soon:

Lock190

Stuff builds up in the lock mechanisms, and powdered lubricants like graphite actually make things worse. The full monty includes carefully removing all the pins and springs, and cleaning everything with solvents. Then you can put it all back together dry, no lube needed. But this requires fine tweezers, a loupe or magnifier (or maybe young eyes), and a lot of patience.

The half monty is keeping the key in place to retain the pins, and dipping the whole assembly in solvent. But enough dirt and grease will remain so that it needs a lube. In this case, I finish with a pressure wash with carb cleaner and a couple of drops of thin oil, or a spray like Kroil. If your lock is jammed with dirt like the OP, you can try this cleaning procedure in place. But if the pins are worn, you will have to take it apart or replace it.