Rusty Brake disc

[Mike'A]

The off side rear brake disc is rusty on the outside edge about a quarter of an inch, I'm up to speed on the fact that discs are made of milder steel to accommodate the fact that brake pads no longer contain aspestos and rust is quite comman place, however after returning home I've noticed the temperature of this disc is considerably less than the others, brakes slow the vehicle down fine, if I brake hard some of the rust disappears and the temperature is equal on all four discs, could this be a caliper or pad problem? I've been told pads do not float freely some times. Vehicle is 13 months old and has 11000 miles on the clock. I would appreciate any input, thanks!

Mike

[M1tchy]

How often do you drive it? How often is it stood static and for how long?

My brakes rust when I wash it and are orange before I've finished. I returned from 7 months in Iraq and they were rusted solid and took a 150 mile drive to fix (at high speeds). They were fine after that. For my subsequent deployments I sprayed them with WD40 and left them for 6-8 months then carefully drove around the barracks randomly braking as hard as possible until I was happy they were at full braking power again.

[Mike'A]

The rust on the outer edge isn't the same as that that may gather over night, its a different colour. If I brake hard and remove the majority of it the disc beneath is discoloured, I'm assuming the discolouration is ingrained rust. I'm intrigued in the fact that the temperature of the disc is different to the others and why this should be. Anyone else got an appinion?