Xantia - MOT failure, air bag light

[Jaf]

Don’t worry, got it off!

[Jaf]

Annnnd got the secondhand one on! Light went off but it’ll take a few starts and drives before I’m certain it’s good.

[xantia_v6]

To avoid another failure, it would be a good idea to check that your steering is correctly centralised.

Assuming that the steering wheel is stright when driving in a straight line, count the umber of turns and part turns from straight ahead to full lock in either direction. They should match.

[Jaf]

Thanks. Years ago I used to do wheel alignment as part of my job, it feels good to me. When the new tyres come they will also check alignment, I’ll get them to have a look at the track rods ends to see if they’re equal too. I saw some really bad ones. Hope I didn’t mess up anyone’s airbag!!

[xantia_v6]

The important thing is that the steering wheel does not rotate too many degrees from straight ahead in either direction. The designers did not allow for much tolerance on the length of the clock spring, and they fail much faster if they are slightly over-wound in either direction.

[Jaf]

Been for retest, all good! Thanks everyone for the help.

[Stickyfinger]

Just for info

How do you check a replacement clock spring is centred ?

[Hell Razor5543]

I think that (before fitting) there are a couple of arrow head markers that line up when it is centralised. If you rotate it one turn in a direction I think that one arrowhead moves 90 degrees round in the direction it rotated.

[van ordinaire]

I had a similar issue with the red Cherokee, which seems to have fixed itself (in itself a little worrying) but while I was trying to work out what caused it to come on - or possibly not go off - it got me thinking about what it actually means. If it's a check light to confirm the system's working, what does it coming on/not going off randomly tell me?

[Jaf]

Mine has 4 x 360% turns, you can feel the spring tension increasing at the extreme end of the turns each way. The secondhand one was at 1 turn, so I set it at 2 turns.