Left: Oversized German helmet I'll call the bezel
Center: Old ignition lock
Right: New ignition lock
Got in my car and key won't turn. Check forums and tried everything short of the vibrating sander trick. Walk over to my MB dealer and order the part.
You'll notice the same part #'s. Upon installation discovered that the circular washer like tab at the end of the old lock makes it slightly longer than the new part. New lock works without the bezel but not with. Key won't turn at all. Has anyone else encountered this?

My replacement was the exact same size as the old one....maybe they ordered the wrong part #? Might be for a different vehicle.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

You're kidding me, right?

buy a new key, I swear I have posted this very same answer a couple of times...for no reason my key wouldn't work on my 1990 300, simply overnight for no reason. went and bought a new key and it's worked fine for 2 years plus. i still have the old key and look at it and compare to the new key...looks the same to me but the old key will not work and the new key does....swear to god that's the truth....

The new key works fine in the new ignition as does old key and the valet key. The problem seems to be the cylinder is shorter so it goes further into the lock. When you put the bezel on there is a gap between the head of the cylinder and the the edge of the bezel. The key will go in but it is binding against the bezel and will not turn. You can see from the photos the difference in length due to that ring at the bottom end of the old cylinder.

Looks like the part # on the cylinder on the right starts with 126, the one on the left with 124.

__________________
Question Authority before it Questions you.

Is the key face on the new one curved inward instead of flat? If so, its a W126 cylinder. W124 cylinders are flat and longer....W126 are indeed shorter. Looks like you've ended up with the wrong part.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I'd not risk it....my W124 cylinder was broken, and it was by sheer luck that it held together without jamming until I replaced it. It fell apart in two pieces in my hand once removed. Replace them! I went with an unmatched unit to the car and it was only $23 with two keys.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

And that's the part I got after giving them my VIN number.
Thanks for the help.

Went back to the dealer and explained the situation. He showed me that the original part # had been superseded by 4 other newer #'s and that the one I have now is the latest correct part. He thinks there maybe a shorter bezel or one of the the 3 other cylinders may fit correctly. Will update as the situation develops.

When the ignition cylinder in my '87 300D (124, concave face) was acting up, I installed one from my '91 350SDL (126, flat face). No difference, fit perfectly.

__________________

Gone to the dark side

- Jeff

do whatever it takes, all I know is what I mentioned worked .... you want the whole ignition assembly..do it...best of luck

Too true, sometimes it is a worn key, not the cylinder (or a combination). Also, a worn key wears out the cylinder faster.

__________________

Gone to the dark side

- Jeff

Interesting, the older W126's have an inward curved face on the cylinder....

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

So, if you have a 1987 300E and need to change the ignition cylinder out with a new one from the dealer, get replacement part 124-462-28-23 also. This is the bezel that surrounds the cylinder. It's about $16.