I've seen this happen on so many late model cars. The rear rotors rust up because the sliders seize. The pads are like new but they say the rotors must be replaced. How do you get around repairing the surface of the rotors so the rear brakes function, which they never do and that is why the problem in the first place. This is on my Mini Cooper. Any great money saving ideas out there?
talking to a few people and the ones I've seen. the outside looks good but the inside is done, pad and rotor . Ive had a few with just some rust so i chucked them in the lath and knocked it off. maybe 10 thou a side. before sticking them back on. It will cost a dealer more to spend the time to resurface them then to replace them and they will lose money if they have to look at them twice. Most don't even cast in the Min thickness anymore remove and replace is the way its done. if it were me and I didn't have a lath Id just free up the slider sand off the rust and stick them back on. The older harley callipers used to stick on the sliders so every now and then Id give it a beating with a rubber mallet and that worked well but you didn't need to pull the wheel to get at it
That is common on most cars /trucks with 4w discs.. mostly happens for two reasons..very little use of rear brakes about 70-75% of the braking is done on the front discs..I have dome many with rear rotors as you described and do not have seized sliders..they just rust from little to no pad pressure to the rotors to keep them clean..Working the trade for many years and I have not seen a solution to the problem..I have always thought they need a little pressure to the rears but when I have tried to play with that I ran into my A$$ passing me on a slippery patch because they grabbed too much and I have tried several times to play with that with no luck.. It is a pain especially on a vehicle that is not driven daily..Seems like from my memory those old minis never had any brakes on the front or the rear... you could probably close off the fluid to the rear and never notice a difference when braking under any operating condition. I know I use wheel bearing grease to lube the pins and slides ,it seems to work better than any antisieze or store bought slide lube and as I say I still see the rear rotors severely rusted with sliders functioning just fine...