The car is a 1981 300SD. About a month ago the ignition key seemed to have one less click and feel easier to turn. At that time, the headlight warning buzzer would remain on with the headlights off when the key was in the ignition. I figure that a switch got worn out. Today a mechanic parked the vehicle and turned the car off with the steering wheel perfectly straight. We couldn't get the key to turn after several tries until we added some WD-40 and it still took a couple of minutes. Can this problem be remedied with a new tumbler and key, or is the problem with the locking pin?

BTW, I always turn the wheel 45 degrees before I turn off the car to avoid having the steering wheel lock up, but sometimes I forget and don't want to be stranded if I forget again.

Thanks

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'81 300SD

Hmm, usually the key tumblers wear out and that causes the key to become very difficult to turn. Usually you would replace the tumbler, and you are good to go. However, I think you may have a problem with the actual steering lock where the ignition switch and key tumbler mate together. That being said I have a feeling that you might have to replace the whole steering lock mechanism as well as the tumbler.



Number 1 and 7 mate together, and there is a small metal connecting shaft which sometimes gets broken. That would explain why you are missing a click, either that or the ignition switch needs replacing.

From here you should remove the key tumbler, followed by the steering lock assembly to inspect them out of the car. Hard to diagnose over the internet, but I think one or more of these items is failing in your case.

A few like myself have had the innards of the steering Colum lock mess-up. The symptoms are the same.

On my 1984 you need the key in the tumbler removal position in order to remove the Ignition switch on the bottom.

If it happend to me again I would remove the tumbler and the steering coulum lock and check inside for broken parts.

Also when I had the Steering Colum Lock apart I found that the Ignition Switch had contacts that were burned off. A new Steering Colum Lock comes with a new Ignition switch.

My steering Colum Lock thread
Steering Colum Lock (Ignition Lock Housing) causes Ignition Switch Failure

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84 300D, 82 Volvo 244Gl Diesel

Will grinding the pin off the lock fix this?

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84 300SD
85 380SE
83 528e
95 318ic

I've owned Mercedes diesels since the early 1980s and have run into this problem at least 3 times.... In fact, in my case, the key got stuck and could not be removed.... I used piano wire to stick into the small release hole while jiggling the key and was able to finally pull the assembly out ..... Also, it's been my experience that you don't want to ever put WD-40 in any Mercedes Benz lock!,,,,, use graphite lock lubricant..... generally, if it gets to that point more than likely a replacement is in order...... I feel you pain, good luck

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Currently Driving
2006 E320 CDI
1999 E300 Turbo Diesl
2002 ML500
1995 E320 Station Wagon


MBs I've owned
1997 E320 Assassinated by Pine Tree
1987 300E Wife Killed Engine
1981 300D Stretch Limo Total Loss
1970 250 Coupe 212,000 mi.
1974 450sel 184,000 mi.
1974 240D 377,000 mi.
1977 300D 204, 000 mi.
1979 280se God Only Knows!
1983 240D 130,000 mi.
1972 220D 280,000 mi.
1983 300SD 244,000 mi.

Replace the steering lock and tumbler now. If not, you can plan on drilling and grinding out the lock on your back for hours.

The tumbler is basically ruined now since you sprayed WD40 in it. All that does is attract dirt and dust from everything and it will only make the tumbler stick worse before it locks up.

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'80 300SD - '83 240D - '00 E55 AMG - '02 G500

If you are speaking of the Pin that locks the Steering Colum Lock top the bracket no. The Pin keeps you from removing the Steering Colum Lock unless the key is in the same position you need to remove the Tumbler.

When I got the new Steering Colum Lock I opted to push that pin in and epoxy it into the depressed state. That holds the Steering Colum Locking Bolt in the retracted position and keeps it from ever locking the steering Colum and with the pin epoxied in the retracted position even if my Lock Tumbler malfunctions I can get the Steering Colum Lock out with out grinding that pine.

Attached Thumbnails

 

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84 300D, 82 Volvo 244Gl Diesel

I think that he's speaking of the pin that DieselGiant grinds away at with a Dremel in this link: http://www.dieselgiant.com/repairignitionlock.htm

I'm thinking that this will be my first course of action before I order a new tumbler. I can get a Febi tumbler for $25 with keys, any idea how much the OEM tumbler from the dealer will cost?

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'81 300SD

Perhaps a minority opinion but I use WD-40 on all of the locks in my Household, Cars and especially out door Pad Locks.

It is pretty dry here in S. CA some dust but nothing heavy. I have had sticky outdoor pad locks but hosing them out with WD-40 has never failed to free them up.

WD-40 has some rust inhibiting capacities but it is on the poor side because it evaporates with in a Month.

Unless it is suspended in a liquid and pressurized Graphite will not flush anything out of the lock mechanism and Graphite itself has zero rust inhibiting to it.

I have been using the WD-40 or similar generic products on locks since the 1970's and I am satisfied with it.

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84 300D, 82 Volvo 244Gl Diesel

Prices reported are rather old $65 (about 4 years ago) on up for the Dealer Generic one, that means it won't fit your key.

I say on up because different dealerships seem to charge different prices for the same item.

The aftermarket Tumblers have been known to last only a year or so.

I bought a Meyle Tumbler before I came acoss a real Mercedes one that matched the Part number of the one that came off of the Car for $50 but with only one key on eBay and I also bought that as the price seemed resonable.

But, I installed the Meyle one (it fit fine) to see how long it will hold up and the experiment has been working since Sep 2017.

Also it seems like Dealer parts for the older cars is drying up.

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84 300D, 82 Volvo 244Gl Diesel

The Classic Center will sell you the correct lock cylinder with the matching key for LE$$ than any Dealer will plus they'll mail it to your door.....

DW40 is a solvent and nothing more.

Using it in any key lock is foolish to the extreme, graphite is the proper thing to use and will ensure decades of easy operation .

As a Mechanic I've replaced many locks ruined by WD40 .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Still it has kept my locks working since the 1970s.


Here is the material data sheet. There is Base Oil in it.
https://www.wd40.com/files/pdf/msds-wd482671453.pdf

https://www.wd40company.com/files/pdf/sds/mup/wd-40-multi-use-product-aerosol-sds-us-ghs-7-20-14.pdf

Previous to the WF-40 use I had used powdered Graphite in a plastic tube that you squeezed and it blew the powder into the lock.

What WD-40 does not do well is as a penetrating oil.

I have used it on lots of squeaky metal parts that hinges and since the squeekie went away I assume there is some lubricating quality to WD-40

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84 300D, 82 Volvo 244Gl Diesel

WD-40 was for water displacement. It's right there in the name. That's why you used to spray it on the distributor points at the spray wand car wash - when you foolishly washed your engine and then it would not start.

But, truth told, I use it for squeaks.

I paid $60 at the dealer about five years ago. You must drive there and present ID and proof of ownership of the car then drive back and present ID to pick it up. They won't ship.

Actually, the ignition and four new keys cost me a little over $80 total. I think they give you one with the purchase of the tumblers.

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84 300SD
85 380SE
83 528e
95 318ic

First off, it's a cylinder, not a tumbler. Remove it and check it's condition. You may indeed have a problem with the lock itself.

Here is my technique for repairing ignition cylinders. If you have access to new wafers, you can replace them rather than grind, but I have no idea where you would find them. Grinding has always worked for me:

Lock190

This shows a 201 lock being repaired, other models are variations on the theme. I think the mechanism is best left dry, as long as it's very clean. Graphite is repeatedly recommended here, and I repeatedly explain that everything solid that goes into the lock stays there: graphite deposits will gradually build until it's a problem. An oily spray will attract dirt, but at least it can be flushed out a solvent. And the very worst results will occur if you use graphite on a dirty cylinder. If a lubricant is used, I suggest a dry silicone spray which can be obtained at a locksmith. But no matter what, you want to start with a clean lock.