Hmmm, brass dust? I wounder if that's my problem.

My key does not want to turn. It's like the cylinder is jammed. If I jiggle it a bit, or a lot it will then suddenly turn.

My car has 450,000 miles and the key that came with it appears to be brass and very worn (lots of miles).

I got new keys from the dealer, nice sharp steel.

But is sounds like brass keys wear and the shavings or minute bits of brass over the years jam the lock cylinder.

Can you just remove the cylinder and tap or blow out some of the filling to free up the lock instead of installing a new one?

You should be able to clean out the tumblers with a solvent although I'm not sure what's the best one to use. Just make sure you do NOT oil it after you're done. Buy some graphite from a locksmith shop and coat all the pins before you reassemble things. Oil is bad news in locks. It attracts and holds dirt from the key and will jam things up again.

maybe brake cleaner? that stuff is clear, lacking any sticky goo. just for flushing and dries clean very fast.

has anyone ever been able to clean out a lock cylinder that has been messed up with a brass key?

For the love of Mike, please, PLEASE just buy a new VIN-coded lock cylinder from the dealer! The ~$75 is far less than the ~$500 bill you'll get from a repair shop that has to drill out the steering column to replace the lock. (Don't ask me how I know this.) The new lock cylinder will even come with a new steel key as a bonus.

That said - what you describe is a classic case of a tumbler about to seize. After it does sieze, you're screwed, as the key must turn in order to replace the cylinder.

As for lubricant, the only thing I would recommend (especially for vehicles with factory alarm systems) is the Mercedes lock lubricant, part number 001-989-26-51-10. It's $12.50 MSRP, and the pressurized canister will lube all the lock cylinders on probably a dozen cars. Well worth the cost.

Oh, and toss those brass keys in the trash.

:euro:

warm WD-40, spray, follow with appropriate lock mechanism lube.

warm anhydrous alchohol is also good, but tricky to keep warm.

ahh man, I nursed my tumbler along for too many years with the above methods, the key finally wont go back in. My mechanic had to drill it out. They charged me $500 to do it. That steel is super hard like a safe or something! I should have spent the $100 on the VIN coded tumbler when I still had the chance.

I use a little WD 40 twice a year. Works.

Broke is Broke - fix it now or it will fix you later

local dealer here charged me $140 last year for a new tumbler w/key for my 190D. And I could never get the old one out, so I just passed the new tumbler & key along to the new owner to mess with. The old one was fine, just was aftermarket without matching VIN# key.

probably about the same cost for my 124. Still not sure I know how to get the tumbler out. sounds easy but my experience has not been good.

One of my 300SD's developed the can't turn key syndrome once in awhile. it turned out to be the mechanism that locks the steering was preventing the key from turning. Might have been dust and grime buildup from over zealous oiling,,,

$500 ? ouch. Better way if totally "stuck": see post #11:

http://www.peachparts.com/shopforum/tech-help/82226-ignition-key-will-not-turn-help.html?highlight=diamond

is it acceptable to drive with a bypassed ignition lock assembly?
 

the ignition key in my '82 w123 (240d) failed to work. i took dieselgiant.com advice (thank you!!!) on grinding down the pin potruding into the steering column. regardless the key still did not work! i bypassed the system by removing the vacuum lines and plugging them before starting...
glowplugs don't work but a squirt of WD40 does it everytime... I just short connectors on starter ad it comes right up
and unplugging the vacuum lines to kill the car!

my question is will continued use in this state cause any damage to the electrical sys or otherwise???

thank you for any input!
john

Lemme get this straight. You start the car with WD40, bypassed the vacuum system, short electrical connections to engage the starter... and you're worried about damaging things? I must be missing something.

Sorry, my input is "fix it properly". Can't help otherwise.

:blink:

correct, right on the money! i concurr but currently my wallet and chronometer do not ;(( are there any obvious culprits you can think of?

thanks for your opinion!

For the cost of a tank of fuel (or less if you want a cheap one) you can get a new tumbler.