I got a used 2002 ES 300 with about 59,000 on it. The dealer installed 4 brand new brakes. I drove the car for about 300 miles now, brakes still make a lot of "scrubbing" or "grinding noise" at a low speed and when stopping. They told me to drive it for 500 miles and it should go away.
Will it go away? They brakes work fine, but the noise is bad, and it's embarrasing. I asked a mechanic at a Goodyear shop to check the brakes, he said the are all brand new, but the metal is very "hard" because the brakes are low grade. Is there such thing as "low grade" brakes? Did they put cheap brakes on my Lexus? Should I wait for another 200 miles for the noise to go away? Is it safe for the car?
Would appreciate suggestions.
Thank you

If he said "Low Grade" then maybe they ARE cheap brakes. And when he said the metal is hard? What metal is hard? Are the brake pads are hard or the rotors??? Oh and the grinding, that's usually the sound of the rotors wearing off from brake pads but I'm not sure if this is happening in your case. I sugggest you go to a friend who knows about this stuff. If not then get some new brake pads.

Take them back off one afternoon & apply some anti-squeak to the pad, shim & piston faces.
No medium-hard stopping on new pads for 100 miles. No meidum-hard stopping on new rotors for 1000.