1985 300D: the ignition switch tumbler has failed. Thankfully I was able to turn the key to position 1 and shut off the engine using the STOP lever on the engine. I then removed the ground on the battery.

With the key in position 1, I am able to insert a release wire through the hole in the tumbler about 1 inch. With the wire inserted I am still unable to unscrew the screw on cap. It is loose (moves from side to side) but the cap will not turn counterclockwise.

I have done this procedure a few times in the past and never had this problem. I am guessing that the square pin in the tumbler is not retracting into the tumbler far enough to allow the screw on cap to turn.

The tumbler is a genuine MBZ part that is only 2 years old.

Any suggestions? Thanks very much.

Help

To hit the release you have to be in the exact place. Take a light and look into the hole and make sure exactly where the release is located. It sounds to me as if you're missing the release.

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84 300SD
85 380SE
83 528e
95 318ic

What are you using for a release wire? What is it's diameter?
Maybe the wire is too soft or too thin to push the square pin in all the way.

In addition to the good advice given, grab the collar tightly with your fingers and twist it back and forth with force till it turns. If that does not free it, tape up the jaws of a pair of pliers (so it does not slip or mar the collar) and twist it off. It could be just hanging on some sharp edges.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I am using a straightened wire paper clip that fits the hole perfectly. Is the square detent supposed to retract into the tumbler when the key is turned to position 1?

No. Position 1 lines up the holes so you can insert the tool to retract the detent. It is the act of pushing on the tool (paper clip) that retracts the detent.

Edit: In case you are not doing it right. You must push the tool in and twist the collar at the same time.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

OK, I will try to twist the collar and push in on the wire at the same time and report back. Thanks.

If it is the standard size paper clip it is probably too thin and soft. You need to push slightly outward to get full retraction.
There is a thread started by Demothen back on 03/03/16 that has the same problem. See my post #10. Of course like many theads on this and other forums, the final solution was not posted.

Rick76 - I am going to get a drill bit that is 1.5 mm in diameter and try that instead of the paper clip. When you say the release pin needs to be pushed in an "outward" direction what exactly does that mean? Thanks.

Away from the center.

__________________
84 300SD
85 380SE
83 528e
95 318ic

OK, I will report back.

It is the tool that needs to be pushed in an outward direction.

Drill bit may be too brittle and may snap if you try to bend it, then you'll have fun trying to get the broken piece out. A small jewelers screw driver will be stiffer than the paper clip and not be as brittle as a drill bit.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

The final solution to my thread was never posted because I never got mine to release . I have been busy with a dash swap and lots of refurb work and gave up on it for now, since my tumbler is still working.