w123: lock tumbler fell out of door
 

Last night, without warning, the key in the driver's side door would turn the tumbler 360 degrees and without resistance. When I went to remove the key, the entire tumbler came out with the key (see picture).

The passenger door tumbler also doesn't work, moving 360 degrees without resistance. That happened a few years ago when I got the car back from a budget paint job. Perhaps the driver's side tumbler problem is related to the same paint job.

Does anybody have tips for me on the theory of operation and how to repair?

This is a 1985 300D.

Here is part of the FSM that shows removal of the outer door handle:

Mercedes-Benz Model 123 - Disc 2

The document you mention has a dead link for the door handle. I think this is the link you mean, though:
http://dream-world.dyndns.org/~jonas/W123/W123%20service%20manual/Chassis/72-240.pdf

Thanks!

-John

I have the same issue on my '85, actually.

The key tumbler is connected to a rod that in turn is threaded through the linkage that actuates the door lock mechanism. If the key turns freely, chances are that rod is broken off. From what I can see of how it's made, there is no way to replace it.

When I tried to switch the tumbler into a good handle assembly with the rod still in place, I ended up breaking it (it was corroded and even after soaking in various loosening agents for days prior to working on it, the rod broke off when I tried to work on it).

Can anyone explain in clear terms how to remove the tumbler from an outside door handle?

I asked this once before and was told "Just look at it, it's easy." Eh. Not for me, so much.

It's a pdf file and you have to wait for it to load. That is the Mercedes Startek site for the FSM. Sometimes it gets busy and it takes another try or wait a bit.

Iirc, you take out a clip, and the tumbler falls out...

Hmmm, okay I guess the spare one I had was too old and rotted to work with then. I thought it looked like the clip I was going to take off, when the assembly broke completely.

Will try to get a set from a better climate.

I just had mine apart to replace the o-ring so the locks do not freeze up any more.

There is a little roll pin that attaches the long shaft with a flat on the end which turns the lock mechanism.

To reinstall the door lock cylinder, put the key in the cylinder to be sure all the tabs are pulled in, then put the o-ring on and insert the lock into the handle. Then from the back side, there is a torsion spring that needs to be wound and put in place.

Once that is done the long shaft with the flat on the end fits over the tab on the end of the lock and a small roll pin is driven into the shaft and through the lock, which keeps the cylinder from pulling out.