Corrosion on inside of new discs

[RichB]

Hi Guys.

Whilst changing the handbrake cables I noticed the inside of my ~6 month old discs have about a 1cm ring of corrosion around the outside of the disc like the pad isnt contacting properly. I used Brembo HC discs and Brembo pads when swapping them. What could be causing this? Not driving it hard enough?

Thanks

 

[Advikaz]

My 200 did this. Cleaned up the rear caliper & they've been fine since.