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I've got a Mazda B2300 pickup that's started making a grinding sound whenever I come to a stop. Braking at a high speed doesn't make any noise, but once I get under 25-30 MPH, the grinding sound gets progressively worse until the truck comes to a stop. What's the most probable cause of this?

Update:

I replaced the front brake pads on Saturday and discovered that one of them had worn completely down to the backing. I had to replace the rotor as well, since there was severe wear on the mating surface.

Doresoom
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  • Were your brake pads bad? I have the same problem, but I looked at my pads and they are fine. My next thought is that my broken wheel stud has something to do with it. Any suggestions? –  May 12 '11 at 23:13
  • @phlip: See the update section in the answer. Yes, one of the pads was bad. – Doresoom May 12 '11 at 23:32

2 Answers2

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Consider the possibility that the brakes make the noise at all speeds but that higher speeds mask it.

The most likely cause is worn pads/shoes. You should check their remaining thickness against the manufacturer's recommended minimum. (Look in a repair manual if you have one, or search the Web.) Check the thickness of the brake rotors, too.

If the car has been left to sit for a few days, corrosion on the brake rotors can cause brake noise until it is scraped off by the pads.

With some brake pads, particularly metallic or semi-metallic ones, it is normal to hear a mild grinding noise when braking.

William Cline
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    Good point about the possibility of the noise being present at all speeds. I've got a friend who's done brakes before who has offered to help me this weekend. He said it was most likely the pads as well. – Doresoom Apr 15 '11 at 16:15
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if it sounds like you're grinding rocks it's probably because your CV joint has gone bad and needs to be replaced.

Sam Rosario
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  • Nope, it was a completely worn down pad that was damaging the rotor. Your suggestion may be useful for someone else though. – Doresoom Nov 29 '15 at 05:19