Replacing Lock tumblers
 

My wife and I have both noticed that the drivers door lock is sometimes hard to get the key into, it seems to be sticking part-way in (although it just turns just fine), and I get the feeling that it's possibly time to replace it.

Seeing as how the ignition tumbler is bound to have seen just as much use as that lock, and how I have to go to the dealership to get the door lock anyhow, should I go ahead an order an ignition tumbler as a preventative measure?

Maybe I'm completley wrong, and I just need a judicious applcation of some suitable lock lubricant, not WD40, I'm guessing - Molybdenum disulphite, perhaps?

I haven't had any problem with my doors but I have replaced the iginition tumbler. My tumbler came out in two pieces and you could see where there was a weak spot in the casting. I would just try some lubricant in the door but if there is any binding or looseness in the ignition, get it replaced.

glenmore
1991 300CE
1990 Ls400
2000 C280

The only type of lubricant to be used in a lock is graphite powder. Anything else will actually attract dirt.

Mercedes have had a problem with locks too. I wasn't aware that GM was too. Thanks for sharing.