Damaged Locking Head

[Dormouse]

I have just fitted a set of Michelin Primacy 3's to our 3008 and I had difficulty locating the locking bolt adaptor on the osf wheel. What I found was a cracked ring.

has anyone had this before and can it be caused by using an impact gun?

[Sloppysod]

First things first, as you have found a cracked wheel bolt, don't use it as you dont know how deep the crack is! And, are there any other bolts affected by cracks you can't see?

I had to replace mine on my C5, one of the pins in the adapter sheared off, I repaired the adapter just enough to enable my local tyre fitter to remove the affected bolt with his impact driver, it was not easy!!
If you buy aftermarket bolts, which I did, make sure the length is right, too short and you will strip the threads. Another problem I now have is the security head is slightly larger on the locking bolt than the others so I had to buy another set of chrome covers for 19mm bolts, from the outside you would never know and I have 20 of these larger covers collecting dust!!.

[Dormouse]

Don't worry - all 4 locking bolts are now replaced. The crack is all the way down the collar so the collar has swollen ever so slightly. That is why I knew there was something wrong as the key would not just slip on. I tore my knee ligaments about 4 months ago and had to entrust the car to a local garage to fit two new front springs for it's MOT. I had found one was cracked but I just fit pairs while I am at it - just how I do things. I am suspicious about impact wrenches and locking nuts/bolts. I have never used powered tools on wheels - ever. My question is " can impact wrenches damage locking bolts like this" or is it just a coincidence that the first time I trust anyone else to touch my cars this happens?
Looking at the rust in the crack it is not fresh and the collar was ok when I put the winter tyres on last October. They should have been changed long ago but my knee has put paid to a lot of things this year and I hate having my cars worked on if I can't at least see what's happening.

[Dormouse]

I have had "discussions" about impact wrenches for over 40 years now. It all started in a friend's garage in Aberdeen. I was put up against the young mechanic to take two wheels off a Cortina against the clock. He had an air gun, I used my own power bar. He had the rears (handbrake on), I had the fronts. Loser made the coffees (my main reason for visiting the garage on cold winter's days).
I was beat - by 6 seconds!
In all my time as a rally service mechanic I never used power wrenches either to change wheels, even in the workshop between events. I trust the feel I have over the tightness or otherwise of the thread.
Don't get me wrong, I have used impact wrenches to good effect. I just don't go to them first as a matter of course.

[white exec]

I use an air wrench at home to quickly remove road wheels, and lightly spin on the bolts again — if doing more than one wheel. All tightening is done with a torque wrench.

Crazy the tightness tyre bays inflict, along with the 3bar+ pressure in refitted tyres. Car rental outfits no better...

[Dormouse]

If everyone was careful with an air gun I wouldn't be so bothered but most don't seem to realise just what they are doing let alone check the torque setting on the gun.