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I just had all my brakes, calipers, and something else related to that replaced. Brand new. And they're working perfectly. So why are they squealing whenever I touch the brake pedal?

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3 Answers 3

up vote 3 down vote accepted

Sounds like they didn't put any disk brake quite on the back of the pads, or used cheap pads without shims, or just didn't use them.

See my answer here for more information

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You could try breaking in the new pad and rotor combination with several hard stops from 50-60 mph. Or better yet go back to the shop and ask.

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1  
I wouldn't do that. You risk causing damage because they are not broken in that can result in your rotor warping earlier than usual. –  denver Apr 28 '14 at 13:25

Sounds like the brake pads and/or disc brake rotors have become "glazed". There are many types of brake pads and rotors on the market from after market suppliers but not all are the same, each range has there own pros and cons. Typically brake pads require a particular bedding procedure as outlined by the manufacturer, but some pads such as TRW's Cotec range boast a less rigorous bedding procedure than their competitors.

Other brake pads may contain ceramic based compounds for better resistance to "brake fade" which occurs at higher temperatures when repeated braking takes place. Normally if you take your car to a workshop they will follow a stringent procedure for preventing them from squeaking afterwards such as below:

  1. Remove the old brake pads
  2. Remove excess brake dust from the remaining assembly
  3. Skim or replace the old rotors (skimming uses a brake lathe and turns the disc brake rotors to make the surface responsive to the new pads during bedding)
  4. Place the new pads in with an anti-seize compound around the sliders and where the brake pads mount
  5. Spray disc brake quiet on the rear of the brake pad to prevent excess vibrations and noise on the brake pads during braking
  6. Ensure the assembly is complete with original shims or replacement shims etc
  7. Bed the brake pads in correctly as in the procedure mentioned by Joel H above

If the mechanics who changed out your brakes followed this procedure or something close to, your brakes shouldn't be squealing. Brake pads normally become glazed if the they are not bedded in correctly and the surface becomes very shiny like glass. If you want to fix it yourself, take the pads out and lightly sand them with emery paper.

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