I seem to have the opposite of rear brake binding, as the outer surface of the rear discs are covered in rust spots. I’ve been out for a drive and carried out some harsh braking but the rear discs aren’t getting ‘shiny’. Also measured surface temps after the 40 minute drive. Rears 50-60deg C, fronts were 90-120deg C.
Vehicle has been sat for a few months, but even before that they’ve always had rusty looking surfaces.
Any ideas?
2010 5.0SC. 2010 Supercharged

Check for seized sliding pins and piston. Brake bias is however very much to the front so difficult to remove rust once it’s formed without prolonged driving. 2012 TDV8 Vogue (L322)