My previous post about not cranking did not have any replies, but thanx to an old post from Metricman and a little patience I have removed the tumbler from my steering ignition column and found the internal coupling to the electrical side of the switch very loose and appears to not turn the electrical element.

Do I have to remove the whole steering lock assy to replace the switch? I still can not find this in the CD, so I assume with the steering lock disengaged and removing the single internal wrenching screw, the lock assy slides out and I can remove and replace the switch itself. I'll be tinkering on it tonite and any advice or hints will be appreciated.

By the way, here in Atlanta there was 2" of snow when I woke up and it is going to get down into the teens tonite! We have a small hill in the front yard and the kids sledded all day!

Best Regards,

You have to take out the pinch bolt that holds the lock assy in. Once it is out, you will have to turn the tumbler to position 2 (if it is out, you are in the correct position), then push the little button that holds in the lock. It is located toward the steering wheel and is small. I usually use a 90 degree pick to do the job.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

I found the section in the CD and thanks for the tip. I will try it in the morning!

I feel like an idiot coming to the board for every l;ittle step, but a bit an ounce of prevention is worth a pound of cure.

I found the release pin hidden behind the steering column shroud and it released as Benzmac promised it would. The wire harness plugg in the back of the lock assy is still engaged and I can not get it out for the life of me. I have grasped the plug with a pair of pliers and pulled pretty hard only to se it budge a tiny bit. Does the cylonder/lock assy have to be clocked to a certain position to remove the plug? I do not see any plastic locking clip on the plug either. I can not extract the whole lock assy while the wire harness is engaged, so I am kind of stuck at this point until I make it over this hurdle.

I am taking baby steps, which I guess is OK since it is 14 degrees F outside and in the garage. I drove my VW cabriolet yesterday as the backup vehicle, but did not put the top down! I am swinging by the MB dealer to ask a question, maybe they can help me.

Merry Christmas!

For those who are interested, I am better than half way done! It is disassembled and I am educated on the hard ware. There are a few interesting twists I will share with you that explain why I had a hard time taking it apart. It might help you some day.

There are three basic elements.. the tumbler, the steering lock, and the switch. As most of us already know from reading the posts, the key (tumbler) has to be in the "1" position to start the removal process. A jammed tumbler in the off position means a nasty surgical extraction of the whole steering lock assy with a die grinder. The tumbler engages a cam in the steering lock that retracts the lock pin itself. This cam in turn is keyed to the shaft in the switch. Lastly, the switch has a "tee" protruding out the back side which engages a slot in the wire harness plug. I guess this prevents a thief from just unplugging the wire harness and installing his own switch and driving off. So there four rotating pieces all in a line, end to end (the thigh bone is connected to the knee bone, the knee bone is connected to the shin bone...).

To remove the lock cylinder from the column, the system is still must be in the "1" position (tumbler removed, but system not rotated) and the wire harness has to be disconnected to allow the required rotation of the lock cylinder to pull it out.

It seems the common failure mode is for the cam in the steering lock to shear, which allows the key/tumbler to turn as normal, the cam to retract the steering lock, but then does not turn the ignition switch. Hence, even though my tumbler was in the "1" position, the tee in the wire harness to switch connection was not, and I could not get the plug off, not fully remove the steering lock (can you hear me swearing?). Carefully extracting the cam and then using a screw driver to turn the ignition switch directly allows for a very easy removal of the connector. My replacement switch did not have the tee, which furhter confused me, but I knew something had to be screwed up!

One word of caution, once the cam is removed, the steering lock spring loads to the lock position. If the lock assy is engaged in the steering column, which is almost required to have room to access the harness plug, you run the risk of getting the lock assy stuck in the column unless you can finagle the cam back in etc. Removal of the key buzzer switch allows a pick to be installed to help hold the position of the lock spring in place while the cam is pushed back in. The Maintenance CD warns about moving the lock cylinder to certain positions without hardware attached in that you can get into irreversible trouble, so be careful!

The MB dealer says the cam failure is common in this year car usually around 130,000 miles. The new hardware is beefed up. They also recommend replacing the switch at the same time as well as the tumbler. Switch is $30, steering lock is $80 (not in stock, so I am still sitting in the garage), and I did not get the tumbler price, but it seems I read it was around $60 in one of the old posts. I asked about the vacuum switch and he said don't bother unless it is oily, but I might change it anyway.

Hope the long post does not bore you, too much info is better than none! (andim finnnalee geting uzed to uzin the spll chacker!)

Hope to be running "Hot and Black" soon!

Deeze,

Thank you for the details and caution notes. I may have to use your instructions somedays. Hope you can get the car running soon.

Happy holidays!

David

David,

You are quite welcome. As I said when this thread started, the first step I take when doing something new, is search for previous advice. In general, many posts are brief and depending on the level of experience of the reader, may not give all the detail and confidence to do some work that is very doable at home. I try to give as much info as possible to help the next guy.

I will never forget the first time I posted a question (a year ago Thanksgiving and a few weeks after I bought the car, and I got the correct answer the next day (from Benzmac himself)!!!! The next saving grace was from you on the brake master cylinder reservoir and bleeding brakes! So I am just trying to repay old debts!

In the spirit of Christmas, it is better to give than receive!!!

What section is the switch removal on the CD ? I want to see if it is on my W123 CD.

__________________
David McDonald
1981 240D
1985 300D (wrecked)
1985 300TD 365,000 miles
1969 Mustang Fastback

Dave,
For the W124 CD, the info is on disc 2, Chasis, Steering, 46-8110. I overlooked it the first search, but found it later. I really dislike not being able to use search functions, but when you do find the correct section, the info is very good.

BTW, I also have a 4" x 7" book that is kind of like a parts manual. I think the official name is "Catalog of Illustrations". I never hear people refer to it in these forums, but I find it a nice compliment to the CD. I think I will do a post and advise members to ask the Partsshop if they have them.

Best Regards,

Maybe MB USA needs to get with Air GTI to help them on their manuals and parts lists being user friendly !

__________________
David McDonald
1981 240D
1985 300D (wrecked)
1985 300TD 365,000 miles
1969 Mustang Fastback

Deezel,

Does the "catalog of illustrations" break down every single part of the chassis and engine, with the part number? My friends 1980 450 SEL, came with a manual like that. Incredible! If PartsShop does not carry them, I see them in Performance Products catalog for $11.95.

I totally agree about the need for a search feature on the CD. I have the paper manuals also, and they are just as bad. There is no way to look up anything in an index. It is a lot of trial and error. For instance the vacuum pump rebuild section is in the chassis manual, not the engine manual.

The car is together and running, though I am waiting for a new tumbler as a preventative step. Here are a final few tips that may help future mechaincs.

Before disassembly, lock at the position of the tumbler relative to the trim. If it is not exactly centered, or even if it is, put some tape on the surrounding structure as a guide line for psotioning the steering lock during assembly. There is quite a bit of slop in the steering lock interface that is eliminated by the clamp. Proper positioning prior to tighttening this clamp will save you time. I had to take my bottom dash panel off three time to get my key positioned perfectly in the center of the trim panel.

For the two release pin W124 tumblers that pull straight out, vs the single release pin that unscrews, at 1 3/8 inches of insertion the release pins begin to to engaged the release springs, at 1.5 inches the pins have fully engaged the release springs. Put a piece of tape or nail polish on your pin at 1.5 inches so you will know you are in all the way. This will be especially helpful for the first timer, since once you know how all this works, things go much smoother. I do not know the dimension for the single release pin tumbler.

And yes Patsy, that is the wonderful little book I am talking about. I put a post on the Partsshop feedback alerting them to the tech page post. I think we should encourage as much business to be sent to the Partsshop to ensure the continued success of this tech forum!

Beep Beep from Atlanta!