Hi folks, new user here. I joined to ask a question for a friend of mine.
Impala, 2004 I believe. He's got 5 distinct, rather deep, grooves in his left rear brake rotor.
All the other rotors appear fine.
He noticed the problem when he heard scraping. The pads appear to have plenty of life left in them, and I'm not sure how many miles, but he's well within warranty.

He took it to the dealer, and they just "polished" the rotor and sent him on his way. The scraping seems to have abated for now, but the grooves are still very much there.

What level of concern should he have? I told him I would take it back, and insist the two rear rotors be replaced. Come time for a brake job (certainly out of warranty by then), the grooves will surely required rotor replacement. Searching the net, I see it's recommended to replace them anyway, as these are composite and turning them is not recommended.

i would most definatly take it to the dealer and insist they replace them thats why they have the warranty. sounds like the dealer is just trying to get out of doing somthing that they wont make any money from.

Thanks for your prompt reply! Any other thoughts? I think it's beyond just a small rock or something that got caught between the pad and rotor, since there are five distinct, rather deep grooves.

sorry bout not getting back sooner. it realy sounds to me like the pads on that side wore to the point that the rivits that hold the pad on were grinding into the pad. the rear brakes on any car/truck with disks seam to be a bit more of a problem becuse they dont get used as hard as the front ones. the caliper may have been sticking and draging the pad on the rotor i would be fighting this out with the dealer becuse like u say when it comes time to do the brakes i would rather not have to pay for rotors that the dealer should have replaced in the first place.