My ignition lock cylinder froze up on my '84 300D in early 2020. I did some vandalism to get it and the ignition switch (by necessity) out, this from under the dash.

The new one I installed was the Genuine M-B item, this one here:

https://www.pelicanparts.com/cgi-bin/ksearch/PEL_search_2016.cgi?command=DWsearch&description=126-462-07-30-MBZ

Not giving Pelican grief in any way, that's where I bought it, you'd think it was the gold standard route.

For the last couple of months the internal spring is so stiff my thumb has a more or less chronic painful spot. Not horrible but annoying as hell. One should not have to put that much muscle into turning the key. The parts of my thumb and forefinger that do the work are getting numb, not exagerating.

From the link, it says the part no longer available. Crap. I recall Kent talking about those probably going on the NA list. Not that a new one would automatically be better but maybe.

Anybody else have this problem?

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1986 300SDL, 362K
1984 300D, 138K

You will be removing and determine the problem before you have a bigger problem. Thanks for reminding me that I need to get the one off the parts car and into safe storage.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

When the key in my 1984 started getting hard to turn I took it apart before my kid broke the key off to make bigger problems. The problem wasn't in the tumblers, which are the first suspect. I pried off the steel cover at the rear side and found there is a spring detent in there. The spring holder is thin die-cast metal which had broken off, leaving the pieces to rattle around inside and sometimes jam the turning. I just left those parts out and pinned & epoxied the cover back. The key rotates easy now but never rotates out of position while driving. I probably should have just removed the steering lock rod while "in there" since I doubt it prevents theft, is a risk of locking the steering wheel while driving. But, most importantly, the steering lock can load the key cylinder when parked so that a dumb kid might try to force the key and break it off (teenagers and/or spouses). Not all know to turn the steering wheel slightly to unload the lock so the key turns easy, or will listen. If you wonder why I didn't trust my kid, he once ripped the net off the back driver's seat when removing a bicycle from the rear seats, a pedal snagged on the net, which frustrated him so just pulled harder. Why he didn't put the bike in the trunk I don't know. He was a medical student then and now a rich M.D so can move on to vandalizing a new high-end M-B or Tesla.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

I thought the real Mercedes parts had a one year warranty?

Just speaking in general from what happened to me. I had the symptoms of a stuck key lock tumbler. But it turned out that the inside of my steering column lock was broken and in more then one place and one of the contact points on the actual ignition switch was burned and it was the arm itself that was making contact.

Replacing the steering column lock with a new one cured the issue. But before I installed the Steering Colum Lock I deactivated the lock spring plunger so that the steering Colum never locks. The advantage of that is you don't turn the key against that spring tension.

About a year and 1/2 later the Lock Tumbler broke. I bought a cheap Meyle one which has been working fine and I also saw a new real Mercedes tumbler and key on eBay and I bought that but never used it.

In your case you could try deactivating the steering Colum lock main spring.

If you do it the way I did you will need to remove the Steering Colum Lock.
After that you turn the Tumbler so that the steering column locking plunger retracts inside and you press in that (brass colored?) button on the side and turn the Tumbler back and let the button get locked in the depressed position.
Make sure the button is all the way and desegregate the area with brake cleaner and let that dry. Fill in the button area with the slow curing JB Weld epoxy and tape over that so that the epoxy will follow cylindrical contour.
Let it cure in a warm area for about 4 hours. Remove the tape and fill in any voids in the epoxy with more epoxy and re-tape. Remove the tape and do any contouring needed on the epoxy so the column lock will return back into place. After that you won't be turning the key against that spring tension but of course won't be able to lock your steering column.
There is an attached picture in post #13 and a red arrow points to the pin that needs to be depressed and epoxied down as if someone one wants to do as I mentioned.
Removal of steering lock bar in 83 300sd

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84 300D, 82 Volvo 244Gl Diesel

I thought the real Mercedes parts had a one year warranty?

Just speaking in general from what happened to me. I had the symptoms of a stuck key lock tumbler. But it turned out that the inside of my steering column lock was broken and in more then one place and one of the contact points on the actual ignition switch was burned and it was the arm itself that was making contact.

Replacing the steering column lock with a new one cured the issue. But before I installed the Steering Colum Lock I deactivated the lock spring plunger so that the steering Colum never locks. The advantage of that is you don't turn the key against that spring tension.

About a year and 1/2 later the Lock Tumbler broke. I bought a cheap Meyle one which has been working fine and I also saw a new real Mercedes tumbler and key on eBay and I bought that but never used it.

In your case you could try deactivating the steering Colum lock main spring.

If you do it the way I did you will need to remove the Steering Colum Lock.
After that you turn the Tumbler so that the steering column locking plunger retracts inside and you press in that (brass colored?) button on the side and turn the Tumbler back and let the button get locked in the depressed position.
Make sure the button is all the way and desegregate the area with brake cleaner and let that dry. Fill in the button area with the slow curing JB Weld epoxy and tape over that so that the epoxy will follow cylindrical contour.
Let it cure in a warm area for about 4 hours. Remove the tape and fill in any voids in the epoxy with more epoxy and re-tape. Remove the tape and do any contouring needed on the epoxy so the column lock will return back into place. After that you won't be turning the key against that spring tension but of course won't be able to lock your steering column.
There is an attached picture in post #13 and a red arrow points to the pin that needs to be depressed and epoxied down as if someone one wants to do as I mentioned.
Removal of steering lock bar in 83 300sd

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84 300D, 82 Volvo 244Gl Diesel

The tumblers, Febi, seem fine. It's the spring action in the switch that's doing it I think. I agree on the lack of real need for a steering wheel lock anymore, they can be a pain if something goes wrong.

Good advice, I'll take a look at it soon. Fortunately the key shows no sign of bending but it's bound to happen methinks.

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1986 300SDL, 362K
1984 300D, 138K

Would be frustrating to see a nice bone yard W123 and want to get at the ignition/steering lock switch. Would be old but you could at least experiment with rebuilding it. Not sure how you would get it out w/o the key.

Kent offers rebuilt units for $375.

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1986 300SDL, 362K
1984 300D, 138K

W123 key switch sticking / stuck

W123 key switch sticking / stuck


Sent from my iPhone using Tapatalk

BTW, the Car Talk radio show (Click N Clack brothers) had an episode where a guy called about a similar 300D key being hard to turn. Their answer was to replace the key tumbler. I was screaming "No, probably the spring detent in the rear of the key housing since mine broke and the design looked weak so all will eventually break and jam." But they couldn't hear me over the radio.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

I'm a little embarrassed to admit this, as I changed the tumblers and steering wheel lock assemblies in both my SDL and 300D, as well the part pictured. But I can't remember which part has the spring in it. My best guess is that it's not this but the steering wheel lock.



BTW, these guys claim to have the whole assembly in stock:

http://www.new-part.com/product/mercedes-w123-w126-300-steering-lock-housing-oem

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1986 300SDL, 362K
1984 300D, 138K

4.19.21 It says out of stock....

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

I wonder what sort of work-around will be found. Rebuilding old units I'm guessing. If only pick 'n pull left a key in the ignition.

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1986 300SDL, 362K
1984 300D, 138K

I want to do this to all my(3) W123's. I have cleaned the tumblers which has helped a great deal but I want to kill the steering locks. Why wouldn't a big strong hose clamp aver the button work just as well or better than JB weld?

The whole assembly, steering wheel lock included prolly so.

Pelican does list this part as still available though.



https://www.pelicanparts.com/More_Info/2025450104M56.htm?pn=202-545-01-04-M56&bt=Y&fs=0&SVSVSI=3305

I forgot I have that part new, long story. Anyway, yes, it is the place where the spring in question is located. All I need to do is swap that in. I forget the difficulties involved but I'm sure it will come back to me.

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1986 300SDL, 362K
1984 300D, 138K

That part is the switch. There is no spring inside, or if there is it is tiny and provides little resistance. It is fairly easy to remove if you can get a flat-blade screwdriver in from the backside, without being able to see the screws. Drives me nuts. I used a special curved screwdriver, but likely there is a special M-B tool to stay on the screwhead. Once I was so frustrated I pulled the whole key-stalk off, which requires bending the dash out a bit to rotate the stalk.

As stated, the spring detent which can jam is behind flat steel plate which is crimped to the die-cast housing. The plate is opposite the steering-lock stalk. You must remove the key-stalk. I don't recall an axial spring on the steering lock shaft, it just moves in and out as the key assembly rotates. While in-there, I would just remove the steering-lock shaft.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans