disk brake rotor with grooves
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.