General Will beating a panel trigger airbags?

[Xen]

I know, a pretty bizarre question.

TLDR; If I take a lump hammer to the spare wheel well to straighten it out, could it trigger the airbags?

Longer: My mums 62 panda was rear-ended seemingly square-on whilst parked nearly 2 years ago.
Unluckily, driver drove away. Luckily, it must have been a very low-fronted car as no damage to boot or the boot lip. Fixed it up with a scrapyard bumper and reinforcement bar. Been through a couple of MOT's since and the mechanic is happy with it. The only problem remaining is that the spare wheel well is pushed up and a bit forward, so the boot floor isn't flat with the wheel in anymore because it doesn't sit in the well properly.
I figured the airbag system is probably just a couple of crush sensors on the front so I should be able to just beat it out with a lump hammer, but I haven't dared risk it. There's no sort of shock sensor or anything that could be triggered, is there?

 

[AndyRKett]

There's no sort of shock sensor or anything that could be triggered, is there?

Yes of course there is a shock sensor in the air bag unit itself.

It is unlikely you would trigger it unless you decided to do the work with the keys in the ignition, but that being said any issues can be easily avoided by disconnecting the battery while you work.

 

[Xen]

Yep, will definitely be disconnecting the battery! I'm probably overthinking it to be honest, but you know those jobs you wish you never started? Don't want it to turn in to one of those because I've not considered something.

 

[Herts Hillhopper]

The whole SRS Sysyem (supplementary restraint system, which includes the airbags but also seat belt tensioners, fuel cut off etc, as well as seat occupancy) is much more complex than ‘just a couple of crush sensors’. It uses a series of sensors to work out speed and direction of travel (including sideways), as well as rate of deceleration and direction of impact. This means, for example, the front airbags won’t go off if you’re hit from behind. If you are struck from the side, only the side bags ‘fire’. The whole system will only operate if the ignition is on.

To get the airbags to go off needs you to decelerate rapidly, eg by hitting something at some speed (over 30 mph I think) and that speed rapidly dropping, which you’re never going to recreate by ‘just’ hitting the wheel well with a hammer.

That said, it’s wise to disconnect the battery when doing many jobs in the car, as this takes away the risk of an accidental short circuit if you catch a wire.

Edit: for those who are interested, general SRS system info can be found here https://en.m.wikipedia.org/wiki/Airbag

 

[TTR]

Eh up

Can you use a Jack with blocks to push out the worst ?

More control this way - unless of course your good with hammer and dolly - not my strength body work but I’ve managed with this method

 

[Xen]

I worded that poorly - I'm aware there's a lot more than just crush sensors in the system I meant more that the only external sensors would probably be crush sensors at the front. The accelerometers will be integrated in to the airbag control module which I guess is probably up near the centre console. There's nothing near the back I could upset, is there?

That said, it has just occurred to me that if that was the case, they'd have probably already been triggered with the original impact!

 

[Xen]

Can you use a Jack with blocks to push out the worst ?

I tried that but because the well is slightly bowl shaped, the jack just pops up before its made any progress I also tried deflating the spare tyre, sitting it in and inflating it, but there's not enough force there. It's tougher than I expected!