Ignition Switch problem 1981 300 SD. - PeachParts Mercedes-Benz Forum

firemediceric · #1 10-12-2006, 07:55 PM

Yet another hiccup with the 1981 300 SD.

I went to start the car this afternoon and the key would not turn. After a couple of tries, the key turned and I was on my way.

I remembered in all of my recent reading on this forum that this is a symptom of imminent cataustrophic disaster. I only had to start the car one more time to get back home. It worked fine that time.

Since then the car has been sitting in the driveway and I have been searching for threads on this issue. I have also read the Diesel Giant how to.

Do you guys feel that I only need to replace the key cylinder, or should I replace the entire ignition mechanisim.

Any advice, as well as direction to posts on how to do it as well as how to disassemble the dash will be greatly appreciated. Many of the links in the old threads no longer work. I guess I'll be doing more searching tomorrow

whunter · #2 10-12-2006, 08:55 PM

Ignition Cylinder Tumbler replacement; mixed diesel/gas
http://www.peachparts.com/shopforum/showthread.php?p=1065596

firemediceric · #3 10-12-2006, 09:53 PM

Thank you. All of those threads should give me plenty of reading tomorrow.

300SD81 · #4 10-12-2006, 10:16 PM

Check to make sure its your key cylinder and not your steering lock. I drilled a hole in my steering lock while the pin was inside and broke the bit in there when mine broke so it could never come out. No need to worry about it popping out when the car is on if the bit falls out since the internal mechanism still holds it in.

gregszustak · #5 10-12-2006, 10:20 PM

I had a similar problem. Found info on this site for a teflon based oil (brand??)
Whoever posted it said it was recommended by a locksmith, freed my ignition key and I am also able to use the passenger side lock.
Might be an easier fix.
WD 40 didn't do the trick.
Came in a small black bottle from a small hardware store

firemediceric · #6 10-13-2006, 09:07 AM

My eyes are blurry from reading all the threads relating to this, and I have many more to read. I haven't even started to search yet how to disassemble the dash on this '81 300 SD.

As I take a break for a while, I have a few questions. I have the 126 body style, I'm pretty sure. See how ignorant I am about this car? The Diesel Giant instructions are for an '85 300 D, same animal? What about the 123? Same instructions apply? I have also seen posts regarding E class cars and others.

I have seen some posts about removing the key cylinder and using a screwdriver in place of a key. I am not at all concerned about theft with this car. Is this an option for me? Other than the theft issue and the obvious "tackiness" about using a screwdriver for a key, what are the drawbacks? Would the steering wheel lock still cause me a problem?

If I can remove the cylinder and use a screwdriver to keep driving the car without fear of being stranded, that's what I'll do, for now.

I'm trying to digest all of the information I can before I tear into this. Thanks for all of your help. whunter posting the links to the threads was a huge time saver.

vstech · #7 10-13-2006, 09:21 AM

I think 80 was the last year for the 116 body style. I hope you don't use a screwdriver on the car, but it is yours to do with as you please...keep reading.
John

firemediceric · #8 10-13-2006, 09:41 AM

I've been looking at some pictures of other cars and I'm pretty sure I have the 126.

In my continued reading, I see that most MB dealers can have a replacement cylinder in ablut 3 days for me. That's not too bad, but the closest dealer is an hour away from me. Just a pain, but oh well.

I have read conflicting statements as to whether any trim pieces have to come off before removing the cylinder. Any clarification?

Do I understand correctly that once the new cylinder goes in, or if I use a screwdriver in the meantime, that as long as the ignition turns I do not need to worry about a lock up of the steering wheel lock causing me a problem?

Bill Ladd · #9 10-13-2006, 10:01 AM

After reading many links here and the DieselGiant pictoral, then talking to a buddy who is a AAA locksmith, I was able to fix his ingnition in about an hour.

The key absolutely would not turn. Wasn't sure if it was the lock tumbler or the entire assembly at fault.

After looking at all required to remove/replace the ingition lock assembly, I was praying for a simple tumbler replacement.

Anyway, after trying everything I'd read about and still not being able to get that key to turn, I called my locksmith friend. He suggested I flush, flush, flush the key slot with brake cleaner, contact cleaner or WD-40 until it runs clear (This to remove all the impacted grahite and other crud). Then tap on the bottom of the assembly whilst attempting to turn the key.

He said it was essential to tap directly parallel to the the key slot. After we flushed all the crud out of the tumbler, I crawled up under the dash and tapped with a large screwdriver and hammer while the car owner turned the key. Almost immediately the key turned.

After a few hoots and hollers, I then followed the Dieselgiant instructions for removing/replacing the tumbler. Now his key turns quickly and easily everytime.

I'd say replace the tumbler while you can still turn that key. As long as you are able to get it in the first position, you can easily get it out.

edit: If you can still turn the key, all you have to remove is the black plastic cover around the tumbler on the dash face. If the key is stuck, you'll need to take off the panels below the dash face to get to the assembly to tap on it. If the entire assembly needs to be replaced, well then you get to pull off all kinds of fun and exciting bits!

firemediceric · #10 10-13-2006, 12:19 PM

In my reading, I thought the "black plastic cover around the tumbler on the dash face" was screwed on and could only be removed once the cylinder was out. Is this a different piece?

JamesStein · #11 10-13-2006, 01:45 PM

It is screwed on. However, it holds the tumbler in. You need to get the key into position 1, then unscrew that collar while pressing on the dent. Then the tumber will come free.

#12 10-13-2006, 01:52 PM

I do not know what (if any) similarities exist between a 126 and 123 ignition, but my problem was that the shaft between the tumbler and the switch broke. This turned out to be a very BIG PROBLEM because the ignition has to be turned to unlock the connector from the switch. I spent three hours chipping my switch apart to release the connector. I had over fiver hours in the whole project. I recommend that you check for this.

Bill Ladd · #13 10-13-2006, 05:28 PM

Quote:

Originally Posted by firemediceric

In my reading, I thought the "black plastic cover around the tumbler on the dash face" was screwed on and could only be removed once the cylinder was out. Is this a different piece?

Not the piece I'm talking about. And that piece is not plastic -- it's hardened steel. There's a plastic surround on the dash of SD's that snaps off.

firemediceric · #14 10-13-2006, 07:54 PM

Thanks for the clarification. Just a screwdriver to pry it off?

I'm going to do more reading tomorrow and then I'll tackle it on Sunday.

If I have this right, and please correct me if I don't, I can snap off the round black plastic trim piece, put the key in postion 1, use the wire tool to press in and release the cylinder, and while pulling straight out on the key, the cylinder will come out.

At this point I can use a screwdriver to start the car and order my new cylinder which will just slide in. Right?

Bill Ladd · #15 10-13-2006, 08:46 PM

Quote:

Originally Posted by firemediceric

Thanks for the clarification. Just a screwdriver to pry it off?

I'm going to do more reading tomorrow and then I'll tackle it on Sunday.

If I have this right, and please correct me if I don't, I can snap off the round black plastic trim piece, put the key in postion 1, use the wire tool to press in and release the cylinder, and while pulling straight out on the key, the cylinder will come out.

At this point I can use a screwdriver to start the car and order my new cylinder which will just slide in. Right?

I'm not sure how the plastic piece is supposed to come off -- mine's busted and is held on with strategically placed electrical tape.

Once that is off, turn the key to the first position, stick a large staightened paper clip into the hole. This will push down the metal tab which then allows the black ring to thread off. Once that's off, you will be able to slide the old tumbler out and install the new.

Give me a sec and I'll post a link to the DieselGiant pictoral.