300CD: Yep, ignition tumbler turns no more
 

Well, it finally happened. Wife drove the car about 8 miles away and there it sits. Ignition tumbler won't move. From the looks of the details of the removal/replacement job (for tumbler not turning) in the Haynes manual, this problem is no joy to fix. I can't seem to find the job in any of the factory manuals - is it there?

Looks like www.dieselgiant.com has a lengthy and helpful write-up. Anything anyone would like to add? I'd sure appreciate the help. I replaced the cylinder head on this vehicle and survived it successfully (so did the car, thankfully:)), so hopefully I can handle this one successfully. Looks like I'll have to get the vehicle towed back home. With the steering wheel locked, will I have to have it put on the truck's bed? Or just lift up the front wheels?

I'll gratefully accept any advice on this one. Thanks-

This just happened on my 84 SD- with a 123 tumbler in the 126 steering lock. My friend had the car at the time and sprayed wd40 in the lock and let it sit for awhile and went back later to try it and sure enough, got it to turn.

If you get it to turn again, by all means do not remove that key unless you're taking the tumbler out with it!

my SD now has the matching ignition tumbler in it as well now, finally!

I'll go try WD-40
 

Thanks for the tip on this. I'm leaving now to go put some WD-40 in tonight and then try it tomorrow morning. Fingers crossed.

yesterday I went by the dealer and tried to order a new tumbler for the one twenty three and he said my vin was no good. I looked again and found that the number I gave him was correct.

Anybody had this experience?

Tom W

VIN and Tumbler
 

TW,

Something is screwed up at the dealer level
(Mis-entered your VIN...Off in Inner Space...Who knows?)
If it's the Aluminum Tag at the A pillar and "They" won't take it,they're wrong.

Call the Nice Folks at 1-800 222-0100 And I'll bet they will recognize your VIN.

DOGGUY,

Act of desperation...A member had luck with a hand sander...'clamped the key in the sander and then successfully turned the key to the correct position for
tumbler removal.(Vibrations are not all Evil)

You know why this worked right? look up bump-9 on youtube. There are some really cool videos on cutting broken MB/BMW, etc tumblers out.

Thanks for the suggestions.

I found an inexpensive hand sander at the Harbor Freight web site - $15. Have to see if I can somehow attach it to the key and then try and turn the tumbler or...perhaps try and turn the key while holding the hand sander against the tumbler from underneath...?

Update (success)
 

Happily, I was able to eventually get the tumbler to turn to the second detent (the “ignition on” position) and ultimately remove it without going through the “can’t get the tumbler to turn” (horrifying) procedure discussed at dieselgiant.com.

Briefly:
1. I removed the key itself from the black plastic “fob”. This way, I would more easily and effectively deal with it during the procedure.
2. I acquired a hand orbital sander (item #40070) from Harbor Freight (around US $10.00).
3. I turned on the sander while touching the vibrating part to the key. I just worked it back and forth on the key for several 30-second periods. BE CAREFUL TO HOLD THE SANDER SO AS TO PREVENT IT FROM TOUCHING THE INSTRUMENT CLUSTER FACING AND/OR DASHBOARD AND DAMAGING IT/THEM.
4. Carefully, I used a pair of pliers to grip the key head and turn it left and right repeatedly in an effort to ultimately get it to turn to the second detent. This didn’t work the first few tries.
5. I repeated steps 3. and 4. multiple times.
6. I sprayed some Wurth HHS 2000 lubricant into the key hole. Several days earlier, I had done the same thing with WD-40 and let it sit overnight.
7. Eventually, using the pliers and carefully gripping the key head, I was able to get the tumbler to successfully (without forcing it) turn to the second detent.
8. The next step was to insert a straightened small paperclip into the slot on the side of the tumbler so as to force the pawl located on the side of the tumbler to retract. This is required so that the black metal ring on the outside of the tumbler can be unscrewed. Remember that you must keep pushing in the paperclip (that is, retracting the pawl) until the black metal ring is completely unscrewed. NOTE: The instructions stated to line-up the slot on the tumbler to the second detent and then insert the paperclip to force the pawl to retract. This was not helpful and didn’t work. I used a very bright light while carefully turning the tumbler until I could see down the side of the tumbler and discover the hole where the paperclip would go. It turned out that the tumbler had to be turned back a bit toward the first detent in order to find the pawl hole.
9. Next, the tumbler and black metal ring lift out of the car completely.

Miscellaneous:
A. I’ve yet to find ignition tumbler replacement instructions in the factory manuals. Instead, I used the Haynes manual (moderately helpful) and the dieselgiant.com instructions (most helpful).
B. With the steering wheel locked, I had the vehicle towed on a flatbed to my garage. There was no way I could do this work without ready access to my tools, chemicals (lubricants), lighting, and 110v power. The tumbler locked-up while the vehicle was in a parking lot about eight miles from home.
C. Once I had the tumbler and black metal ring removed, I did a thorough cleaning of the insides of the ring and what it threads onto since both were well coated in lubricant from earlier work.
D. I had one heck of a time getting the large electrical connector located on the back of the ignition assembly to release. First, the clearance is awful there with the black plastic hose that connects to the left dash vent. I disconnected the hose at the console end and pulled it toward the driver’s door enough to provide clearance behind the electrical connector. Next, you may have to gently and carefully wiggle the key/tumbler a bit in order to get the connector to release. Whatever you do, don’t force it out the connector.
Once I have the replacement tumbler/key from Phil, I’ll be re-installing. From the looks of things, that work should be substantially easier.

Had the same problem last week. Used small vise grip to hold the key. Held massage vibrator to vise grips. Released in matter of seconds. Now I'm trying to figure out if I need a tumbler , steering lock, or both. Good luck.

Installation complete - some final notes
 

1. You *must* have the key/ignition tumbler in the second detent position in order to be able to successfully release the large black plastic electrical connector on the back of the ignition assembly. This is because the connector itself has a hole (shaped like this: |----| )in the center of it which is the receptacle for a pin that is the same shape. When the key/ignition tumbler is in the first detent position, the pin is in the hole and turned and thus is holding the connector in place so that it cannot be removed.
2. The new key/ignition tumbler’s pawl (the *whole* L-shaped thing on the side of the tumbler) must fully retract on installation and fit into its spot perfectly in order for the black metal ring to properly situate. If the ring’s detents don’t line-up fairly closely with the key positions as it did when the car was new or whatever, try the installation again because things are not right yet. In my experience, there will likely be an audible click (probably the pawl completely popping out of the side of the tumbler) when the tumbler and ring finally situate properly and as they should be. If you cannot turn the new key/tumbler with it and the ring installed, things aren’t right – try again. REMEMBER, to release the electrical connector on the rear, you must have the key/tumbler in the second detent position.
My tumbler lasted 245,000 miles/25 years and 9 months. Not bad. In fact, nothing short of remarkable. Just consider how many times that thing was turned. Whew

Call classic parts.

Usually disassembling the whole thing and spraying the steering lock pin with wd40 takes care of the job for me.

Yep,my "79" 240 vin indicates I can not get a key and tumbler to match the rest of the locks in the car. I checked two MB dealers, "NA" so I bought the generic tumbler.

I've got a full matching lockset from an '80 euro 300D.... L & R doors (tumblers are still in the door handles), ignition, trunk AND locking fuel cap, 2 keys (one factory, one not) w/ an expired registration paper so that you can order more keys from the dealer, (I've already done this successfully) for $80 + ship, PM if interested.

Update on ignition tumber, etc.
 

Unfortunately, a few days/drives after completing all of the re-installation activities for the new ignition tumbler, I found that the tumbler wouldn’t turn again (argh). Ultimately, the problem proved to be a failure of the mechanism inside the steering housing lock assembly. This is the gray metal L-shaped assembly (about as long as your outstretched hand) that the ignition tumbler fits into, secures to the steering column, and which locks the steering wheel. Once I had this part out of the vehicle, I could clearly demonstrate that it was the internals of this part that had failed and were causing the steering wheel to remain locked when it shouldn’t have been. This is not to say that the old (original) ignition tumbler was in fine shape. My summary of this project is this: Do not be fooled into thinking (as I was) that after more than 20 years of use, only the ignition tumbler wears. My experience has proven that the highly complicated steering housing lock assembly (and its operation is a fun project to analyze) wears just like most everything else on the vehicle. Now that the ignition tumbler and steering housing lock assembly are new/replaced, everything is tight and smooth – probably how it was in Dec. of 1982 when they built/assembled the vehicle. Good thing all of this lasts so long because this is quite an unpleasant job, ESPECIALLY when you cannot turn the ignition key anymore (my case). And this is coming from the same person who replaced the cylinder head/head gasket on this same vehicle.