how do I check an old airbag?
 

Has anyone had any experience of replacing airbags? At 18 yrs old, some hot years in Singapore when new, the rest in NZ, I doubt the airbags can be trusted.
I am already a tad suspicious as my Daimler has a Jag 'Cat' in the steering wheel centre instead of the "D". There may not even be an airbag in there anymore..the dashboard check lights behave however, so there probably is.
I want to drive my car in the 'press-on' way for which it was designed, so I'd like a functioning airbag should I meet a tree.

I think the only way to check them is to meet a tree. lol

I don't think they can be checked.

I agree with Mike. As I recall from the service manual there's not much that can be checked. There are a couple wiring/resistance checks that might condemn an airbag but nothing that proves one is still good.

Cheers
DD

Have a look at this video from Airbag Systems on testing Airbags and Seat Pretensioners:


This looks to be along the lines of what Doug describes. I've posted it here for information and discussion and not in any way as a recommended procedure.

I'll NOT be interfering with mine. :eek:

Graham

At Jaguar Training classes we were instructed NOT TO DO THIS!!!!!!!!!!!!!!!!!!!!!!!!!!
The proper way is to read the resistance with WDS or PDU through the SRS module.

It is not likely (BUT POSSIBLE) to induce enough current to deploy the airbag but when you have the correct tool, why take a chance.

The moving coil meter is an even worse idea because it can provide more current than the DVOM.

Just my opinion.

bob gauff

^^Yes Bob, but that doesnt guarantee there is a air bag, and a resistor soldered in place(seen it before on salvaged cars) you can always make a test rig with pins to fit the terminals and10' of wires and a car battery. With the air bag face down and the wires pinned into the back. momentarily touch leeds to battery. If the air bag blows up into the air, It WAS good, if it doesnt recheck leeds, if okay then the air bag is NOT good:)
But does anyone remember the decals on older Jags that stated, "REPLACE AIR BAGS AFTER 10 YRS SERVICE" No longer the case anymore, but it does make you wonder huh?

+1 Bob. Depends entirely on what current your meter puts out.
VERY unlikely to set off the igniter but these need treating with caution.
The other point is that all the test does is check the igniter heater is not open circuit.
There's a lot of energetics downstream of the igniter and the bag envelope itself.
After 18 year's cooking just replace it.
Bob will correct me but I believe the service life is ten years.
Disconnect the battery and wait 5 minutes before messing with air bags or you might find they function better than you expect.

Right, and I wouldn't be fussing about with mine, either!

Since this guy/this company appears to specialize in airbags I'll give them credit for (probably) knowing more on the subject than I ever will.

However......

I'm a little nervous and disturbed at (what appears to me) as over simplification of the testing and conclusions.

As Bob said there is some degree of risk involved in checking air bags. The guy in the video makes no mention of this. I'm not a nervous-Nellie type generally but messing about with airbags is an area that I make an exception.

And I disagree with his conclusion that passing two resistance tests is outright confirmation that an airbag is "still good". The only way to confirm an airbag is "still good" is if it has deployed when it was intended to deploy.

Cheers
DD

another way to test an old air bag is this.
check pulse at neck or wrist, and or put a mirror under nose to see is she fogs it:)
LOL Cheers, Im off to the country

The gas generator in an airbag of that age is Sodium Azide which has the same toxicity as potassium cyanide.
Later models use a smokeless propellant which is less toxic and much less dangerous chemically.
Sodium azide explosively decomposes into metallic sodium and nitrogen gas.
One of the funniest things I've ever seen not involving Jehovah's Witnesses was someone lobbing a large azide inflator cartridge (for inflating boats) into a swimming pool.
It took off like a demented torpedo. The sodium metal, of course, reacted violently with the water producing loud bright yellow explosions.
After two lengths it hit the shallow end so hard it shot out of the pool and exited through a window.
It's astonishing how quickly people can get out of a swimming pool when the need arises.

Back in my dealership days we occasionally had to deploy air bags and made a bit of an event out of it, calling everyone from all departments (and any customers who were interested) into the shop are to witness the big event.

Good fun...and most were surprised at the amount of explosive force involved.

Cheers
DD