I recall having same problem some years ago on my '85 300D (similar, I believe). It's been a while, but I do remember first using a mirror to get a good look at the screw heads. I tried various screwdrivers, but in the end bought a mini ratchet wrench that would accept a short screwdriver bit. Something like this one:

Mini Ratchet Set | eBay

 

A mirror might help but it is easy to remove the entire assembly. Remove the tumbler and lock assembly. Good time to clean and lube the tumbler while it is still working.

 

I was assuming John was trying to remove the electrical switch of the back.

I stopped short of removing the whole assembly after reading Diesel Giant's page.

Rowdie - Is there an easier way to remove the whole assembly?

By the way John, there is a good picture on Diesel Giant's site (above link) that shows the location of those screws (plug removed). Too bad they didn't use a different head!

(Assuming MB used similar switch on 107s)

 

On the 107 you just have to remove the tumbler. (instructions in the manual) Then loosen the collar on the lock assembly and pull the entire unit. It really is easy.

 

Rowdie,

Which section and page of the manual? I looked but did not see anything except for a reference to the switch as S1/2.

Thanks,
John

 

Thanks MB Graham and Rowdie,

Yes I was trying to remove just the switch to replace it as part of a process of elimination for a no start condition. MB Graham, I like your idea and tried but I just could not get that tactile feel. I like Rowdie's remove-the-whole-thing-and-lube-it but I could not see how I could do so as the dash seems to block that area. Besides, patience is thinning like the paint on my trunk lid:grin

Took a break and then had a fresh go and was able to get it out. I installed the new one with Phillips head screws! I tried so many combos of drivers that I'm not even sure which worked. Then I noticed it was loose. Yay. Noob luck, I guess.

I appreciate your responses.

BTW, the new switch is much stiffer when turning the key. Normal?

Many thanks guys,

John

 

Thanks, MBGraham!

 

M-B person who worked on my 1978 450sl, told me there was a problem with the electrical part of the ignition key. Said he had to 'wiggle' the key to get the blower motor to come on. PO had someone install new tumbler with off brand key. The key for my VIN number will not work. M-B says that they can't sell me a new tumbler. Do you have to take the steering wheel and instrument panel off to remove the electrical section of the ignition switch? I have the manual and it appears you do. And what do I do about the bogus tumbler? M-B person said it was possible that a new tumbler would solve the electrical problem.

 

There is no electrical part of the ignition key. The only electrical part is the switch. The assembly consists of the tumbler, lock and switch. The first two are mechanical. The key turns the tumbler, releases the lock mechanism and engages the switch contacts simultaneously. If you need pics search or I can post in the AM.

 

J..I went through this on my '79. Give me a call..Jerry..870-847-5771..

 

J...Any luck with Tom ?..

 

Hey, J. Called Tom yesterday but he is out until Monday. Will call him then. Scouring the internet to see if I can find a NOS generic tumbler but no luck yet. Thanks--look forward to talking with you more.
Jim

 

Thanks, Rowdie. I'm hoping to find a NOS tumbler and have it re-tumbled to fit the new keys that M-B sent me. Going to call Tom Hansen on Monday. If anyone has a NOS tumbler, please let me know. The keys are VIN specific to my 450sl and if I can get a new generic tumbler redone, it would also be VIN specific. George Murphy has been helping me and we know that the electrical part may also have to be replaced. We're hoping that a new tumbler and key will do the trick. We've been unable to get the blower motor to come on without wiggling the key. But, I'm guessing that if the electrical part is off again/on again, more things than the blower motor are being affected. I have this bad feeling that removal of the entire dash is in my future. Wonder if there is a step by step video on that?

 

Removal of the ignition switch is not that difficult. Steering wheel is probably the hardest part. I prefer to remove the whole lock assembly rather than using a mirror or trying by touch to find the three screws.

 

Classic center has no access to tumblers for any cars before 1981. I tried for many months and all manner of hoops. No tumblers from Classic Germany or Irvine. Not made anymore. Dealer wasted 10 months of my time on that pursuit.

If you want a viable tumbler, source one out of a parts car from the era. I was able to use a w115 tumbler while my OE was being rebuilt by the local locksmith.

 

Classic center has no access to tumblers for any cars before 1981.

Not exactly true the 450SL as of chassis 047076 uses the same tumbler as one for an '81-'85 model. Around 1978-79 MY.

It is a moot point anyway. The tumbler is NLA for any models prior to the 1986 production.

 

Was helping an owner on Peachparts, so looked up the shop manual section on www.tonk.ca. Posting here for future reference!

For the shop manual, go to www.tonk.ca.

If ever I need to do this job, maybe I will find this post!

The ignition switch is not covered in an obvious place! It is under steering, section 46!

https://www.tonk.ca/r107CD1/Program/Chassis/46-640.pdf

 

Was helping an owner on Peachparts, so looked up the shop manual section on www.tonk.ca. Posting here for future reference!

You guys are great