Ignition switch locked up, Key not turning, 1984 300CD - PeachParts Mercedes-Benz Forum

gregp1962 · #1 06-17-2021, 07:43 PM

I had this problem about 3 years ago. I bought a new ignition switch and key. I think it was a new Mercedes part too. but, now it won't turn again.

1) How can I get it to turn so I can get the car home?
2) How can I prevent this from happening again?

BirthdayBenz · #2 06-17-2021, 08:35 PM

I had this happen in my G. It is likely that the key wont turn because the column lock is jammed. Though a completely different vehicle the lock cylinder and how it locks the steering column is the same. In the link below you can ignore how I'm disassembling the dash and jump to the part about pinning the column lock.

https://clubgwagen.com/forum/viewtopic.php?f=18&t=17639&p=167706&hilit=ignition#p167706

BWhitmore · #3 06-17-2021, 08:42 PM

W123 cars have a history of locking ignition switches. A knowledgeable Mercedes mechanic advised to use a genuine Mercedes key and to only have one or two keys on your key ring. Multiple keys on the key ring causes problems. It is worth a try to try to unlock the switch with the key multiple times, otherwise you may have to drill out the hardened lock pin.

jsb357 · #4 06-17-2021, 09:38 PM

W123 key switch sticking / stuck
https://r.tapatalk.com/shareLink/topic?share_fid=31137&share_tid=408467&share_pid=4098722&url=http%3A%2F%2Fwww%2Epeachparts%2Ecom%2Fshopforum%2Fshowthread%2Ephp%3Fp%3D4098722&share_type=t&link_source=app

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gregp1962 · #5 06-17-2021, 10:15 PM

Quote:

Originally Posted by jsb357

W123 key switch sticking / stuck
https://r.tapatalk.com/shareLink/topic?share_fid=31137&share_tid=408467&share_pid=4098722&url=http%3A%2F%2Fwww%2Epeachparts%2Ecom%2Fshopforum%2Fshowthread%2Ephp%3Fp%3D4098722&share_type=t&link_source=app

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Thanks for that link. I was able top get it turned so that I could drive it home. The car is now in my garage with the key in the on position and battery disconnected.

In reading that tech article, I'm gathering that disabling the steering column lock is likely to prevent this from happening in the future. Is that your understanding as well? Also, the tech article wasn't specific on how to disable that steering column lock.

BirthdayBenz... Is the G wagon switch interchangeable with the W123?

BirthdayBenz · #6 06-18-2021, 06:56 AM

They are not directly interchangeable but functionality is identical.

Check out the attached photo I found on the internet. There is a locking pin (circled in red) which is what locks the steering column in place and keeps wheel from turning. When you turn the key this pin is retracted out of the hole in the steering column in the direction of the red arrow.

What I believe is happening is that it's not the key getting jammed in the lock tumblers but rather that this pin is not able to retract. The pin is spring loaded and can be pushed in with your finger and pinned as in my thread on clubgwagen. This prevents the column from ever locking again.

Usaguy · #7 06-18-2021, 08:05 AM

Its not a good idea to be messing around with the steering lock mechanism.

Diesel911 · #8 06-18-2021, 09:18 AM

If you get the key to turn you should as soon as possible get it turned into the proper position to remove the Sleeve that holds in the Lock Tumbler.

Even if you get the Lock Tumbler out and it appears to be OK removing and inspecting the innards of the steering column lock will tell if something is broken inside. That is important because the steering column lock is between the Lock Tumbler and your Ignition Switch.

When I had your issue I found that my Steering Colum Lock was busted in 2 areas inside of it and that the Ignition Switch had one of the contacts points burned off.

Another issue is that that a year or so ago the Steering Colum Lock supply was drying up.

Diesel911 · #9 06-18-2021, 09:27 AM

I thought that this was the typical Lock Tumbler issue till I looked into it
https://www.peachparts.com/shopforum/diesel-discussion/333785-steering-colum-lock-ignition-lock-housing-causes-ignition-switch-failure.html

About a year later this happend:
Thread on my issue: https://www.peachparts.com/shopforum/diesel-discussion/387730-another-type-ignition-lock-tumbler-issue-w123-pictures.html?highlight=steering

Diesel911 · #10 06-18-2021, 09:33 AM

Quote:

Originally Posted by christuna

Its not a good idea to be messing around with the steering lock mechanism.

Parts inside of my Steering Colum Lock were broken. If I had not messed with it I would not have known that.

When I got the new Steering Colum Lock there is a spring loaded button on it that locks it into the Bracket that holds the Steering Colum in if your key is not in that special position and that is want makes the Colums hard to get out if something goes wrong inside of it.

If you push the locking plunger in and depress that Button the locking plunger is will no longer lock. When I got the new Steering Colum Lock I epoxied in that Button in the depressed position so it holds in the locking plunger. I did that back in 2013. Have had zero issues with that and doing that relieves some of the spring tension you turn against when you turn the key. That means your Lock Tumbler does not get as stressed.

gregp1962 · #11 06-18-2021, 10:55 AM

Quote:

Originally Posted by Diesel911

Parts inside of my Steering Colum Lock were broken. If I had not messed with it I would not have known that.

When I got the new Steering Colum Lock there is a spring loaded button on it that locks it into the Bracket that holds the Steering Colum in if your key is not in that special position and that is want makes the Colums hard to get out if something goes wrong inside of it.

If you push the locking plunger in and depress that Button the locking plunger is will no longer lock. When I got the new Steering Colum Lock I epoxied in that Button in the depressed position so it holds in the locking plunger. I did that back in 2013. Have had zero issues with that and doing that relieves some of the spring tension you turn against when you turn the key. That means your Lock Tumbler does not get as stressed.

Thank you Diesel911. If I'm understanding you correctly, I could do that with my current steering lock. Then It won't lock but, it should prevent the problem from happening again, correct?

Diesel911 · #12 06-18-2021, 07:38 PM

Quote:

Originally Posted by gregp1962

Thank you Diesel911. If I'm understanding you correctly, I could do that with my current steering lock. Then It won't lock but, it should prevent the problem from happening again, correct?

No.
There is a issue that is missed. When the Key gets stuck you cannot turn it to the position needed to remove the Sleeve to get the Lock Tumbler out.

You also cannot depress that button that locks it into the Bracket that holds the Steering Colum Lock in place and that means you cannot remove the Steering Colum Lock unless you grind down or drill out that button.

Also on the later models like my 84 300D you cannot remove the Ignition Switch from the inside of the Steering Colum lock because it also has a metal peace that keeps it from being removed unless the key is turned to a specific position.

By epoxying the Button in the depressed position all it means is I can remove the Steering Colum Lock even if the Lock Tumbler won't allow won't allow me to turn it.

BillGrissom · #13 06-19-2021, 06:19 PM

In my 1984 300D, the problem was that a spring-detent broke off to jam turning the assembly. It wasn't a problem with the tumblers jamming, nor a problem with the steering lock rod applying pressure. That detent is underneath the steel plate which is crimped to the aluminum lock housing. Once you pry the cover off, you'll see it. The spring holder came out in pieces. I don't really need those detents since the switch has never rotated out of "run" in the 15 years since I fixed 'er (tossed the broken offending parts). I probably should have taken the steering lock rod at at that time since it isn't of much help today and can only cause problems.