Airbags in practical classics - dead weight?

[davebem]

Airbag light came on recently in one of the my 1990s cars, it happened since the battery died and had to jump start. The manufacturer fault code reader basically said the airbag ecu was dead. Luckily i had a spare one from same model/year in a parts doner car and got it swapped, the diags passed, light cleared in time for MOT. After dismantling the parts car some more it alarmed me how heavy the airbags units are, e.g. in the steering wheel and passenger side dash. As manufacturers usually advise to replace them after 10 years, what is the liklihood that they will actually work and be effective? Has anyone crashed a 25 year or older car and the airbags deployed ok? MOT test checks the airbag light, but is there any point maintaing the system if its expired and the parts are n/a?

[T6 vanman]

I'm sure it'll be fine ..............
Do you spin red and rely on 25 year old steel with the structural integrity of paper machie .. or
Do you spin blue and rely on the cushioning effect of shrapnel from an airbag by the manufacturer Takata

[Riley Blue]

Airbags deployed in our 17 year old Fiesta in a head-on. Mine (driver's) combined with seat belt tightening caused such severe chest pains I was x-rayed in case my sternum was broken. Fortunately it wasn't but I've never been in such pain. Standing up and sitting down was agony and I hardly slept for 10 nights. Very grateful we weren't in our Riley...

[sideways man]

As an ex-car mechanic,who was in the trade when the lifespan of airbags was first talked about, this is a question I’ve thought about.
Sorry, don’t have an answer though.

[davebem]

Riley Blue said:

Airbags deployed in our 17 year old Fiesta in a head-on. Mine (driver's) combined with seat belt tightening caused such severe chest pains I was x-rayed in case my sternum was broken. Fortunately it wasn't but I've never been in such pain. Standing up and sitting down was agony and I hardly slept for 10 nights. Very grateful we weren't in our Riley...

I guess thats another thing thats linked to the airbag ecu and loom which means the system must be maintained: the seatbelt tensionors. As they use some kind of pyro technics to fire usually, perhaps these go past their sell by date too and become dormant?

[MiniGraphite]

Fifth Gear has this one covered -

[kjs62]

I unfortunately ran into an unlit parked lorry on a dark road whilst being blinded by an oncoming car - wrote my 1998 E36 318is Bmw off - prob hit it at about 25mph - my airbag didn't go off which surprised me - maybe it had gone u/s though the light went out fine

[Decky_Q]

They usually dont go off below 30mph as they reckon you're better off without for <30mph shunts. At least that's what I was told by pretty knowledgeable people on an airbag training course, when they were telling us how to check that the system was 'ready'.

[T6 vanman]

kjs62 said:

I unfortunately ran into an unlit parked lorry on a dark road whilst being blinded by an oncoming car - wrote my 1998 E36 318is Bmw off - prob hit it at about 25mph - my airbag didn't go off which surprised me - maybe it had gone u/s though the light went out fine

Was the impact point higher than the crash sensors ... Hidden behind the bumper cover on the crash beam, If you struck the lorry at headlamp/grill height the sensors wouldn't have received the 'G' required to activate.
The ECU requires a 'go' signal from one or more sensors and despite an accident .. if the threshold for 'go' isn't met .. then deployment wont happen