dargeth

hi there all, im new here. i own a RX300 10 months old the problem is, after i drive it for 2mins the back brakes(i think) become noisy, like metal to metal sound but not screeching, my dealer said it was the compound that the brakes were made of, he cleaned them but a week later they r the same, my dealer is puzzled?? has anybody had this problem b4? thanks