New key tumbler 1990 300SE
 

Purchased a new key tumbler for my 1990 300SE from the dealer. Installation seems straight forward to me, but reading up on it I see it can be tricky if not installed right for the later W126 models (1990-1991).

Anything I need to be aware of when installing the new tumbler?

Jorn, if you're using the U-shaped tool for the first time to remove the old tumbler it may take some fiddling to get the tumbler to release. Best to fabricate the U-shaped tool from the largest diameter wire that will fit in the tumbler slots. Like with most things, after you remove the tumbler once you will know the feel to release the keepers if you ever need to replace a tumbler in the future.

We sprayed some light grease into the holes where you insert the tool:

Before grease: impossible to get tool to release.

After grease: almost immediate engaging of tool and release.

Good luck.

RayH

I’m looking to buy one for my 190 do you mind telling me how much you paid ?

Not cheap, $169.24, comes with a new key. Mercedes keys and tumblers are cut in Fort Worth, Texas. Got it in 4 days after ordering one.

Did you greased the tumbler itself before installing it, wondering what kind of grease to use?

Is this actually cut to the VIN for the car, or just a "Shop cylinder"? I only ask because when I went for a spare cylinder for my '91 350SD in 2019, they no longer cut the cylinder for VIN matching, although they could still cut the key.

If you haven't already done so, verify that the key that came with the new cylinder works with the rest of your car and that your existing keys work with the cylinder.

Yes, cut to VIN and works with the rest of the car. They needed the VIN, registration of the car and my ID.

Had to change the tumbler on my old 300CD fifteen years ago and needed to change all the locks because I wanted to use one single key for the locks and ignition and not a different key just for the ignition. Back then they couldn't cut it to VIN for the W123, did cost me $750 for the tumbler, three cylinders and two keys.

Thanks Jorn I knew it wasn’t cheap that’s why I asked the price where did you buy it ? Did you buy it at the dealer in downtown LA ?

Yes, Downtown LA. You have to order it in person.

Yes, I think we did. We did the same on my son's 190D 2.5.

As for the type of grease, I cannot remember but it may have been silicon or white Lithium.

Both come in a spray can.

However, inside the lock itself, into the key hole, I think we used some graphite powder that is favoured for locks. I've also used this on doors and boot.

R

Jorn, I just happened to have written down the exact procedure to get the cylinder out of my '91 300se - built in Oct, 1990. I bet they are the same.

1. Get a 2 mm piece of wire or rod, about 6 " long or so.
2. Grind a 70 degree angle on one end.
3. Turn key to acc position 1.
4. Insert the wire into the hole/slot just to left of the top of the key (approx 12:00 o'clock).
5. Turn the ground side of the wire inward.
6. Press the ground end of the wire outward to pass over the top of the lock cylinder.
7. Then press ground end of wire inward and push in to unlock the pin.

It's been several years since I did it, but I remember messing with it a minute or two getting the feel, then it popped right out.

DG

The hardest part of this job seems to be to find the right 2mm metal rod to make the tool...

We used welding rod.

If that makes sense. I had to buy about 20!! But a single rod did the job.

R

Had to order 10 2mm rods from Amazon.