Scrapping noise from wheels when driving slowly

[mazda3guru]

Hi there, I bought a used Mazda 3 2010 a few weeks ago (new brake pads, checked by another mechanic) and the car has no noise when driving for the first 15-30 minutes. After that you start hearing this noise at low speeds (similar to when your brake pads are gone) even when you don't push the brake pedal. This is especially pronounced when I turn right. I brought it back to the dealer to look at it but there was almost no noise during that time so he thought I'm just too finicky. It comes and goes and I'm not sure what to do. When the noise is present, it concerns me as it doesn't seem trivial. I don't understand how/why there is no noise when you have just turned the car on? What should I tell the dealer this time around? any idea on what's wrong? Please help me.

Thanks
p.s. I'm not car savvy

 

[leeharvey418]

I had the same problem on my RAV4... took it to three different shops before one of them actually bothered to take the caliper off and discover that one pad had broken up and a piece of it was scraping against the rotor.

 

[Schwamm]

I haven't owned a Mazda 3 for long, by my protege has had similar symptoms when wheel bearings are going bad. Jack the car up and listen for noise in the bearing when you spin the tires, and for play in the wheel (it should be rigid when you pull on the top or bottom). Just a thought!