While unbolting the front Brembo calipers on a rotor change I noticed the 2 bolts that hold each caliper were giving me resistance all the way out, on both RH and LH sides.
I thought that was odd and upon removing the calipers so I could have a closer look at the vertical link (Swan Neck Wheel Knuckle) that the bolts were in I noticed the threads on the knuckle in poor condition and aluminium thread bits on the bolt when I removed it and thread bits in the thread shaft.

I cleaned out the thread shaft of all the loose aluminium, dry lubed the bolt and proceeded to screw it back in and out a few times.
I finally got a smooth screw action but 2 threads on both front sides remain damaged..
Not sure if this is connected in any way to the rotor run out I've lived with.

Not sure if I should crucify the local mechanics as yet?

I've never liked steel bolts in alloy and am unsure if I should now helicoil these threads?

I've managed to at least re-assemble everything and get some good torque on the two bolts on each side.

Has anyone seen this before?

 

I am not sure that I would be happy with a heli-coil in that particular application; my preference would be a Wurth Time Sert:

https://www.wurthusa.com/web/en/webs.../time_sert.php

 

+1 on repairing threads or replacing the vertical links, especially if the lower ball joints are in poor condition on a pre-facelift car.

 

Did the x202's have a different ball joint to the x204/x206?
Other than the dealers in its early life and they wouldn't had a need to remove the calipers, there's only 2 mechanics that've ever touched the vehicle. In fact to memory only one ever did the rotors; had them off many time re machining then and trying different pad combinations due to run out every time.
His workers nicely chipped the **** out of the paint finish on the Brembo calipers removing the pins and I suspect the use of the air gun everywhere has been the culprit on the threads here.
My advise to everyone, do your own brakes or supervise the so called mechanics working on the brakes.

 

Update.
I rang the workshop and they claim that this is a common occurrence when they first unscrew bolts out of alloy. The thread damage is due to the lock tight material binding on the threads which was first placed on the bolt at assembly... So of course it's the factory's fault for doing this...
He told me not to worry about it if the bolts are on tight; which they are.

 

The difference is between the X200 and X202 when the design of the upright link was changed. The X200 uses a ball joint that faces downwards.