In my 1986 300SDL there is a driver's side airbag. This device and all of the wiring and firing mechanism are now 30 years old.

What is the opinion here about continuing to have a small bomb ready to go off in your face with a 30 year-old triggering mechanism?

What are the alternatives for replacing the steering wheel? If I had to guess, I'm sure that it is against Federal law to remove the SRS mechanism (even on a 30 year-old car), but this has me a bit frightened. I've seen lots of odd electrically-controlled things happen on cars this old.

Feel free to discuss what you can/can't do in the People's Republic of Kalifornia, but that won't enter into my decision.

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Mike Frederick
1986 300SDL, 240K+ miles
1985 300D KaliKar, 270K+ miles

I am not going to tell you what you should or shouldn't do, as I think nobody can make that call but you.

However, take a look at the PDF file that I attached here, which is the service information for airbag units.

Basically, anything before '92 has a 15 year expiration date which you passed a long time ago. Anything after '92 apparently never needs to be replaced.

Even in modern cars, airbags can sometimes accidentally deploy, so age is not the only factor. Bad luck seems to play a part in it. Boy, it must suck to be on the receiving end of it.
I am always aware when driving a car with airbags (my daily driver) to not have my hand covering the airbag portion of the steering wheel. If it were to go off all of a sudden (or someone pulls out right in front of me or something), I'd hate to get a degloving injury, which can and does happen with airbags.

Attached Files

airbag life span.pdf (6.6 KB, 90 views)

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"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

It's possible it may not even work if you get into an accident.. Why bother removing it. Even if you did, I've never heard of a mechanic taking off the cover to make sure the airbag is there. That's completely unheard of and something no one is paid enough to care about.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Just unplug the wire harness going to it. It is about a 10 minute job.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

I agree. It's not a big deal. Strap the seat belt tight and drive defensively.

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

Found on w124performance.com (which I believe belongs to a member on this board)

http://www.w124performance.com/docs/mb/other/airbag_service_life_2009.pdf

This is a later version of the document posted above.

A little control system theory on what is happening with the air bag controller and the air bag ignitor.

The air bag control module has several diagnostic functions.

The first and most visible is the SRS light illuminating when the vehicle is powered up. On first gen 124s it is about 10 seconds, on later models about 4 seconds. This is the reserve capacitors charging from the vehicle bus. This provides the energy to fire the air bag if your electrical system is compromised during the impact. If the capacitors successfully charge, the light turns off.

The other thing that happens is a supervisory current is constantly sent through the air bag ignitor. This is a low value current that is not enough to heat up the ignitor but enough to confirm its continuity. If the air bag (or bags in later models) or the seat belt tensioner ignitors lose continuity, the SRS light will illuminate.

If you've ever shot an Estes hobby rocket then you are familiar with a solid fuel rocket and the ignitor. An air bag is basically a small solid fuel rocket.

The Estes system provides a supervisory system in the little plastic launch control box. The SRS controller uses a similar concept.

When you attach the clip leads to the rocket ignitor and pull the safety pin on the controller, you complete a circuit of battery -> light bulb -> ignitor. The light bulb limits the current through the ignitor to a value below which it will get hot enough to ignite the solid fuel. But it is enough current to light up the bulb.

The launch button is wired in parallel with the light bulb. When you press the launch button, the light bulb is shorted out, and the full battery voltage is placed across the ignitor, it gets hot enough to ignite the solid fuel, and it launches the rocket.

If you've never shot one of these then if you have a door bell with an illuminated pushbutton it works the same way.

Or an old school gas furnace thermostat with a heat anticipator.

Or a power switchgear circuit breaker control system.

I will continue trusting my W124's air bag.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Put this out there, from experience.

When a Nissan Sentra challenged the Volkswagen Squareback (the latter winning), was thrown around, but didn't hit anything. Being a corner impact, doubt an airbag or inertia belts would have helped.

The '85 300TD-T had S.R.S. seat belts. When the old lady decided to run into us and shorten the Mercedes by about half a meter, was glad for those belts, especially over airbags. Being have a medical condition which at times means have a Service Dog in my lap, if the airbag went off then, the $40,000 investment be dead. The S.R.S. seatbelt did just as good or better, as I did not go forward, nor get burned by the seatbelt since it locked up immediately (inertia wheels apparently leave burns). Believe in them so much, on the look out for another set, or hopefully can still get through Mercedes.

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Current fleet:

1985 Mercedes-Benz 280TE - Waiting for heart surgery.

1985 Mercedes-Benz 300TDT - Rear ended 23 September 2016 and now looking for a new home.

1979 Mercedes-Benz 300TD - Parted out.

1964 Volkswgen Beetle - Vater's since September 1968 and undergoing a restoration.

1971 Volkswagen Sunroof Squareback with F.I. - in need of full restoration.

1971 Volkswagen Squareback automatic with F.I. - Vacationing with her caretaker until he is in better health.

There's is an MB document floating around somewhere that supersedes the 15 year expiry of airbags with a much longer date based on their longer testing and experience since the initial 15 year expiring was imposed. Personally I'd leave it in place.

My 97 SL320 and 97 C280 have stickers on the door jamb listing air bag expiration. At least on the SL there is an update sticker for the drivers wheel bag as this was replaced during some sort of recall.

Air bags were originally designed to save the unbelted so they could continue to be stupid. Early bags were designed to catch an unbelted male weighing ~ 200 Lb, as a result they had to inflate quickly with much force to catch the person accelerating towards the steering wheel.

On the 91 Dodge Spirit I bought for Mom in 95, I disconnected the driver air bag because the risk of injury from the old high power bag is greater than belts.

I'm not sure if the high power bag was used in MB cars or not.

Adriel; You drive around with a dog in your lap? Are you nuts? A lady wiped out both of our cars parked in front of the house when her worthless little dog got excited and tangled up in the steering wheel.

Don't make it a regular occurrence, only when needed medically. The 70 pound Golden have her back legs tucked under and front legs between the seat and the door. Never got stuck, knows to stay laying down. As for the 50 pound Golden retriever mix, even easier as can fold up tighter. He too knows to stay laying down and be calm. If am an hour from home, not like can have someone else drive me, and the pressure allows me to continue on home.

Am also offended you think my Service Dog is worthless. Ember allowed me to drive and volunteer two hours away day after day for several months. Learned too much for us, so don't do it anymore. But, now and then when do make an hour drive, know if do need it, Daithi can help also.

Not any law against it, plus need it medically. Out here, either you drive, or you are S.O.L. and have to stay home and starve; already applied for assistance and was denied (apparently only take those in wheel chairs despite what the publicly posted guidelines are). No friends or family here, so am on my own, absolutely no one to help. Just me and the dogs.

Sorry both your vehicals were totaled. What a bummer, especially if classics.

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Current fleet:

1985 Mercedes-Benz 280TE - Waiting for heart surgery.

1985 Mercedes-Benz 300TDT - Rear ended 23 September 2016 and now looking for a new home.

1979 Mercedes-Benz 300TD - Parted out.

1964 Volkswgen Beetle - Vater's since September 1968 and undergoing a restoration.

1971 Volkswagen Sunroof Squareback with F.I. - in need of full restoration.

1971 Volkswagen Squareback automatic with F.I. - Vacationing with her caretaker until he is in better health.

Don't think he was saying your dog is worthless, he was mad at the ladies dog who caused her to total his car.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Jake, thank you for clarifying. Sometimes even my Autism frustrates myself...

And not just one totaled, but two, F.Y.I..

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Current fleet:

1985 Mercedes-Benz 280TE - Waiting for heart surgery.

1985 Mercedes-Benz 300TDT - Rear ended 23 September 2016 and now looking for a new home.

1979 Mercedes-Benz 300TD - Parted out.

1964 Volkswgen Beetle - Vater's since September 1968 and undergoing a restoration.

1971 Volkswagen Sunroof Squareback with F.I. - in need of full restoration.

1971 Volkswagen Squareback automatic with F.I. - Vacationing with her caretaker until he is in better health.

You make some good points. A device that's been in place for 30 years might be unreliable. This site says that going with the old 10 and 2 hand position on the wheel could be hazardous to your health in the event of an airbag deploy.

How holding the steering wheel at the old '10-and-2' spot could tear off your hands in a crash | Daily Mail Online

I must admit, never heard of or considered the possibility of a degloving injury from an airbag deploy. What a revolting development that would be.

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1986 300SDL, 362K
1984 300D, 138K

True dat Jake12. Thanks.

Her dog was a poodle or ****zu or some such. Just had to try for that squirrel.