A mystery braking sound, please help!

Hello all,
I’m stumped. I have a 2010 hyundai elantra touring with the 2 liter engine. I’ve had a weird sound that I cannot figure out what is causing it. When the car is cold, the brakes make no sound when being used, within a few miles of stop and go driving, the brakes will make a sound when coming to a stop (Not a high speed, only from about 15mph to 0). A loud humming sound. It happens more if I brake hard, and if I brake lightly it will make a less loud sound.

things I’ve tried:

  1. I’ve removed all four wheels to inspect the disc pads, plenty of meat (plus wouldn’t they make a sound braking at any speed and when the car is cold?)
  2. The passenger disc had a chip in it, so I replaced it. Didn’t help with the sound.
  3. The driver side cv axle boot was ripped. Replaced it. Didn’t help.

The car brakes perfectly fine, other than the sound. No pulling to one side or chattering. I’m stumped. Thanks for all your help.

If the car stops fine, can you ignore it? Some pads are noisier than others. This seems minor. My only sugbestion is to change the pads to a different brand or OEM… or live with it.

If I had that problem I’d probably just accept the situation, figuring eventually I’d have to replace the pads and rotor with oem parts, routine maintenance job. If the sound was so annoying I couldn’t ignore, I’d try some 150 grit sandpaper, test if radial oriented sanding marks on the rotor helped.

I suggest replacing the other rotor.
Always change brake parts in l-r pairs.


I wonder how a rotor would get chipped? I’ve never seen that effect myself. Maybe something in the road got thrown up and smacked into the rotor.

Thanks. I guess I should replace the other rotor. And try changing the pads, I think I used Napa, I’ll try a different brand.

Not sure, I’m thinking it may have been damaged during a tire change? Actually I forgot that the garage had overtightened the lug. So they had to replace the lug stud. Could that do anything with the sound?

Unlikely, but worth checking. Ask shop to check rotor run-out.