Ignition switch failure in 1965 190D

[roy]

Hello. I am new and I wanted to post a question. I am not sure I am on the right path as I have been unable to find full instructions on what I am doing. My 1965 190D ignition switch died (the tumbler fell out and all the pins are missing). I ordered a new ignition switch and key but am having a very difficult time replacing. So far, I have removed the instrument cluster, removed the bolts to lower steering column which freed the ignition switch. But I am stuck now trying to remove the unit so I can replace the key switch. The diesel starter knob is attached to the switch and I just can't seem to remove it. Does anyone have advice on what steps I need to take next.

For a brief moment I though I could replace the switch through the space where the gauge cluster was, but the little screws on the sides of the switch are too hard to get to.

I would love any advice. Otherwise, next steps appear to me to try and disconnect more items under dash to try and make room. I'm fearful I will not be able to put all this back together and that there is another way that I am missing! This is my Thanksgiving weekend project!

Thanks, Roy

[Cth350]

I can't speak with experience on the diesel, but for a gasser, I'd first be disconnecting the battery cables and then I'd be removing the wiring from the switch at the back and removing the gauge cluster from the front being very careful with the two lines that carry oil and alcohol and then with the key turned to position 1, where it would sit while driving. Doing that does two things...
1. the shiny chrome cover is freed so it can be pulled up a little
2. the heavy metal pin that's hiding in the steering column would retract.   You know it's free when the body of it can turn with that stem as a pivot.

You very much want the big blue book titled "passenger car models, starting 1959".  It's also available on a much bootlegged CD, but I like having the book in hand.

-CTH
PS. the oil line goes to the oil pressure gauge and a 10mm flare wrench will remove it.  The alcohol line is for the temperature gauge. Both are hollow and fragile, don't bend them at a tight angle or they will be dead. The alcohol line is sealed at both ends, the oil one is open at both ends (so be sure to tighten it or the dash will get a fast lube job.

[roy]

Thank you for the words! I will try again tomorrow. I did forget to mention that I did disconnect the battery first! Which is a good thing considering all the wiring I'm touching.

I do need to get the blue manual. I saw one on eBay. Or at least the cd or pdf. Going blind is not a good thing with this car!

Roy

[roy]

Worked on the ignition some more. Lot's of wiggling and disconnecting of various bolts and wires. And then I figured out how to disconnect the diesel starter cable from the ignition switch along with the wires attached to the switch. Here is a pic hanging under my dash and then out on my table. Only two two hours this morning!



Now here is the next craziness in this stressful project. The new switch comes with a new chrome bezel and attaches with two very tiny screws. But the old switch does not have the two screws, but instead just two metal stumps where the screws should go. So now I'm really clueless as to how to remove the chrome bezel so I can replace the key switch mechanism. All fun.

[roy]

Hi everyone. I was able to finally replace the ignition switch within the steering lock. It was not fun and I had to do this in baby steps as it was frustrating and I was flying blind. But now I know how to do it and I wanted to write down the instructions here in case anyone else ever has to attempt this repair. All in all, it's a good afternoon's project.

Here is how I did it (as an amateur) on my 1965 190D. I also put in a few pics. I should have taken more but wasn't thinking I would get this actually finished. My steps:

Disconnect the battery.
Disconnect the wiring plugs under the dash that the ignition switch wiring plugs into.
Unscrew the diesel starting switch handle.
Remove the gauge cluster. Follow the Mercedes shop manual for this as it was pretty accurate. Mainly about disconnecting the speedometer and oil pressure gauge.
Remove the two nuts holding the bracket that holds the steering column in place. Nuts are in the space where the gauges were.
Remove the long bolt that screws in under dash into the steering wheel lock.

Now this was the hell part. Somehow with one arm through the dash where the gauge cluster was, and another under the dash, grab the ignition lock and somehow finagle it down enough where you can unscrew the three screws attaching the round wiring connection to the back of the steering lock. For a diesel you will also have to disconnect the diesel starting pull switch. It's just one bolt. Then pull out the steering lock from under the dash.

Now we have to remove the ignition lock from the steering lock. There are two pins in the side holding in the ignition lock. These have to be drilled out (I don't know how else to get them out). Then I drilled a small hole into the ignition lock. Then I used a slide hammer with a long metal screw. I screwed the screw into the small hole I drilled and slide hammered it a few times. I had to use a couple screws but after a few hard whacks, it started moving and then came right out.
I oiled the inside of the lock along with the sides where the ignition lock assembly will reside and then took my new lock assembly and placed in in the open whole. It's a very tight fit so I had to tap it in using a small socket fit over the lock (to not damage the lock) using a rubber mallet. A few gentle hits and it started moving in. Once it was in, I tested it and it worked. I will admit the key has slight resistance but I don't know if it's possible to rectify this as to remove the lock again would cause too much damage and another $200 to replace it!

Getting this back in the car was basically the reverse of above but it was not fun. It took me a couple hours. Over an hour of this just getting the steering lock back into place. Not a fun job but I was ecstatic when I hooked up the battery and the key turned and started the car. The first time it ran in a couple months.
I think I wrote down everything I did. Hopefully no one here will ever have to do this, but at least now here is one way to do it. Maybe there is a much easier way, I just couldn't figure it out!

Thanks. Roy