-Treser-

Hi Guys I am struggling with loosening the center bolt of my right axle. Need to replace the inner cv boot but don't dear to use an air hammer on the center bolt.
Always heard the stories that you not allowed to use an air hammer on a car with ceramic brake discs. I tried searching Google for any information relating to these stories but can't find any information. Is this maybe a false story made up by someone thinking that ceramic and hammer doesn't go together? I understand the disks are made of long carbon strands with a polymer that is turned under extreme heat into ceramic.
I hope someone of you knows about anything relating to this matter and if I can safely use an air hammer on these ceramic disks.

03_AR_CO

If you are trying to loosen the center bolt, have the car sitting on the ground and use a long breaker bar. An impact wrench is not the way to go on those bolts.

SS_RTR

Yes, leave car on ground and use the long breaker bar to start. I did mine this way. You should only loosen with one 90 degree turn with wheel on ground or bearing will be damaged (according to Bentley manual). Tightened spec is 200nm without wheels on ground followed by the final 90 degree turn under load.

MP4.2+6.0

+3. Car on ground.

What I do yet more specifically is stick the large allen key socket through the wheel center hole, using a 6" or so socket extension. I support that extension with a jack stand placed along its shaft as close to the breaker bar (wrench handle) as I can. I use an approx. 2ft breaker bar AND slide a 5 or 6 foot pipe over it for the leverage. Hint: floor jack handle turned in reverse = the pipe, and it is presumably strong enough for those kinds of loads. And if it's not, I want to know anyway, and preferably not when I'm jacking... The torque is so high often I end up literally standing on the extended pipe/bar to break it free. Why the jack stand is especially handy to see the allen key socks head well centered even using a lot of force/leverage.

Same technique in reverse to get the needed leverage to tighten it to full torque spec.

I have broken a few extensions and breaker bars doing this over the years. Maybe 20%+ of the time. Thus be prepared body wise if standing on it for that scenario. If it breaks, I just head to Sears with the (Craftsman) bits and shrug my shoulders about how it broke. Definitely use a breaker bar (NO ratchet drives for first breaking loose or final torquing), and the sturdier the better.

Sci-fi_Wasabi

It sounds like you are describing some kind of Olympic diving technique, with you diving off of a 6 foot pipe

-Treser-

Thanks for all your info guys. I got it worked out by placing a bit more weight on the front after lightly jacking up the right rear side, and using a high torque ratchet wrench + a 1,5 meter long steel extension on the front right I got it loose.
Luckily it worked out as I was almost ready to ask my wife to come give me a hand and push the brake. I really didn't want to to that as I am way to scared to put to much force on the ceramic brakes and damage them.

@SS RTR you wrote "You should only loosen with one 90 degree turn with wheel on ground or bearing will be damaged (according to Bentley manual). Tightened spec is 200nm without wheels on ground followed by the final 90 degree turn under load."
Thank you very much for this information :-) Does the Bentley maybe also refer to how we can block the wheel from turning around when forcing 200 nm onto the center bolt when the wheel is of the ground?
I can't get my head around how do this in a way I don't damage anything else like the ceramic brakes or internals of gear box etc. Maybe I am missing something..

Yes @MP4.2+6.0 seen your trick with the jack to support the wrench head as a great help. Do I didn't need it in the end as the bolt came very smooth lose without a sudden snap or brake of anything that was rusted or lock tide ceased.
I just needed that extra length and some more weight on the front end of the car.
Yes I know I shouldn't have used the ratchet wrench but in the end it was the only tool that didn't bend from the point where it is connected to the socket extension and the extension.
2 other tools I had a bended so much I was going to destroy them when I had proceed and had not reached back to the high torque ratchet wrench. I definitely will update my tools and get a better wrench without ratchet to do these sort of extreme jobs. Thanks for all your info really appreciated :-)