'95 E34 525 airbag steering wheel into a '90 535???

[Wallabee]

I have a 90 model 535is (built 4/89), which doesn't have an airbag steering wheel. I have aquired a '95 525 as a donor car for parts, which has an airbag. Does anyone know of any dificulties in fitting this airbag wheel to my older car?
I have found the 'airbag sensor' under the rear seat of the newer car. Are there any other components involved in the airbag system? Is it just a simple connection between the sensor and the airbag?

Cheers, Colin.

[632 Regal]

Can't answer but there are also sensors under the hood on both inner fenderwells up front.

[Wallabee]

OK. Thanks for this. I'll see if I can locate them on the donor car, and have a look at a wiring diagram.

[ltflint]

Pretty sure that the wheel won't even fit. 95's are secured with a 16mm (I think) bolt and the early cars have a 22mm nut to hold the wheel on.

[Wallabee]

Thanks ItFlint. I can probably overcome that as I have a lathe and could do some mods, or replace the whole steering column in my car with the one from the donor car.

[Ross]

There is lot's more to the airbag system, the steering column itself is different, a processor, several(3?) crash sensors and of course lots of attendant wiring. Not something you want to try to retrofit, especially given it controls an explosive device a few inches from your face.
There are two different steering shaft spline sizes on E34s. I'm unsure of the change date but it's a simple enough item to test fit if you prefer the asthetics of the airbag wheel.
You'll find a ready market for the non-airbag wheel in the states if it's in good "nick".

[Wallabee]

Thanks Ross. A check of the Bentley manual indicates that there were two airbag systems, "Airbag I", with just the driver's airbag and sensors on both front fenders and "Airbag II", with driver and passenger airbags and a sensor under the rear seat. However, my donor car seems to have a system thats something inbetween these, with just a driver's airbag, but with a sensor under the rear seat and none on the front fenders.
To retrofit I'd need to swap over the steering column and wheel, fiit the sensor and controller and wire it all up. As you suggest, not something to be taken lightly.
My motivation is safety, not aesthetics. My 535iS has an M Technic sterring wheel (in excellent condition) and looks better than the airbag wheel.
Cheers, Colin

[Ross]

Thanks Ross. A check of the Bentley manual indicates that there were two airbag systems, "Airbag I", with just the driver's airbag and sensors on both front fenders and "Airbag II", with driver and passenger airbags and a sensor under the rear seat. However, my donor car seems to have a system thats something inbetween these, with just a driver's airbag, but with a sensor under the rear seat and none on the front fenders.
To retrofit I'd need to swap over the steering column and wheel, fiit the sensor and controller and wire it all up. As you suggest, not something to be taken lightly.
My motivation is safety, not aesthetics. My 535iS has an M Technic sterring wheel (in excellent condition) and looks better than the airbag wheel.
Cheers, Colin
The SRS system's harness is integrated into the main harness, not a discrete bunch of wires easily swapped. Changing the wire harness is a monumental task.
If airbags mean that much you'd be better served finding another car.