W126 Passenger Airbag Retrofit - PeachParts Mercedes-Benz Forum

tinypanzer · #1 12-02-2014, 07:44 PM

Hello all,

Here's the deal - recently scored a very nice condition dashboard with airbag from a member here. My 560SEL has every single option except dual airbags. Whether or not adding the second bag is even feasible is what I wish to find out, I don't want to stir the whole debate about the pros/cons of airbags in general.

There are several questions I have...

1) Will the passenger airbag work with my SRS module, or do I need to swap?

2) Apart from the bag, the dash, and the passenger side ignition wire, what other parts would I need?

3) Should I just not do this because it could be unsafe? I've torn down and reassembled a W126 dash before, but never tried a conversion. Is it as straightforward as it seems, or am I playing with fire?

Thanks,

-tp

pwogaman · #2 12-02-2014, 09:00 PM

It is somewhat involved.W126 Dual Airbag Retrofit Project

tinypanzer · #3 12-02-2014, 11:30 PM

Quote:

Originally Posted by pwogaman

It is somewhat involved.W126 Dual Airbag Retrofit Project

Thanks for the reply. Actually, I read that article and it seemed to me that he was doing a retrofit from a car without airbags. My car already has a driver's airbag, and therefore an SRS module, seat belt tensioners, etc. The part about the sensors in the the belt buckles interests me, I wonder if there is one that would need to be added on the passenger side or not, I'll try to dig that up.

At any rate, most of the stuff he had to do probably doesn't apply in my case, but some of it very well may.

Thanks,

pwogaman · #4 12-03-2014, 08:41 AM

You do need to change the module and harness. The w124 and w126 use the same modules. Read through this thread.

W124 Passenger Airbag Retrofit Project Completed (with pics)

tinypanzer · #5 12-04-2014, 01:18 AM

Quote:

Originally Posted by pwogaman

You do need to change the module and harness. The w124 and w126 use the same modules. Read through this thread.

W124 Passenger Airbag Retrofit Project Completed (with pics)

Hey, thanks for the reply. I've looked over your threads, and it seems like you had about as much fun as I did when I rebuilt the hvac box on my 300. Yikes. I still recall that out of all of it, the hardest part was reconnecting the bicycle cables on the vent levers. My hands were scratched up for weeks afterwards.

So, I've got the donor dash, the bag, and the bracket that mounts the bag to the dash - the whole thing was shipped in one piece. Not having taken the parts out myself, I'm unclear what I may be missing. The fellow (a member here) wisely included the vent tubing. So I think I have all the pieces north of the bag. Are there any supporting brackets or bars that need to be swapped out, like on your w124? I should mention that the 560 recipient is an '88 (2nd gen w126) so I don't think it'll be as tough as your '85 was.

I should probably contact him about the other parts. Gee, would the forces encountered in shipping "trip" the sensor module, or damage its inertia detector? Then I need the wiring harness I suppose.

Is there a second seat belt sensor I wonder? Man, this is sounding like a real pain in the butt. Anyway, the old dash is pretty cracked and there are a few reasons to go in there already piling up, so I'll have to deal with it somehow. My donor dash has a passenger bag, so unless I find another one as perfect as this, I might as well plunge in. Too bad I can't just pull the bag out and attach my old glovebox, I'd probably just do that at this point.

Anyhow, it'll be spring before I tackle this swap, so just in the research phase now.

Cheers!

BenzEnthusiast · #6 12-04-2014, 01:40 AM

Glad to hear you are happy with the dash.

I spoke with my friend who has done this before and he basically told me, aside from one bracket/brace, the whole upgrade is plug and play, so long as you have a passenger airbag dash.

According to him, the only additional parts you'll need are the new SRS module and the wiring that goes with it and a bracket/brace. The seat belt pre-tensioners and buckles don't have to be changed and neither does anything to do with the driver's airbag.

Apparently, the bracket/brace that has to be added goes from the bottom of the dash near the center console to the side of the transmission tunnel on the passenger side of the car. You'll have to use a self-tapping sheet metal screw to attach the bracket to the transmission tunnel as there won't be the threads to use the factory bolt. Then you might want to add the passenger knee bolster which is also fairly simple to install.

I'm pretty confident that it will turn out nicely since you won't be modifying the dash itself to fit the airbag like some have had to do.

One last thing, he also told me that he once tried to fit a glove box into a passenger airbag dash and said that it was very difficult to get it aligned properly.