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A little more detail about your car would have been very helpful, I'll try my best to help you out!
You seem to have a problem with the brake pads, either they are worn out or if it was replaced recently is not fit properly, I would advice you to go to the mechanic asap.
If it is worn out, or it the disc brakes have lost its integrity, get it changed soon, make sure you install genuine parts from an original dealer.
Make sure the chassis are fine and are not touching or brushing against other metal parts, it could also be a possible reason. Make sure all the bushes are fine and are not worn out.
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