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Having bad brake problems... please help

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by rmoon, Jul 2, 2014.

  1. rmoon

    rmoon New Member

    Joined:
    Jun 25, 2014
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    Location:
    los angeles, ca
    Vehicle:
    2004 Prius
    Model:
    Three
    I just recently purchased a used 2004 prius from a Toyota dealership. I am not sure if its the brakes but when I brake it is making a crazy screeching/grinding noise. This noise is not the normal brake screech and it does not seem to be a grinding noise that you get when the brake pads are worn out. The dealership does not seem to be able to find out what the problem is. I have a 1 month warranty and I have taken the car back 3 times for the mechanic to figure out the problem.
    The biggest disconnect is that the mechanic says everything looks fine and the brake pads are new. The ONLY time I hear the noise is when the car has been sitting for a long time. So basically when the car is not warmed up I hear this noise. After 5-10 mins of driving and braking the noise goes away and the brakes work great. That is what confuses me the most. If anyone has any insight please help, I only have a couple more weeks of warranty left. Thanks all for the help.
     
    #1 rmoon, Jul 2, 2014
  2. jdenenberg

    jdenenberg EE Professor

    Joined:
    Nov 21, 2005
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    Location:
    Trumbull, CT
    Vehicle:
    2020 Prius
    Model:
    LE AWD-e
    Your Prius only uses the brakes in emergency stops and when under 7 MPH. In all other cases regenerative braking (using the electric motor as a generator) slows it down as required. Your rotors then tend to develop rust on the surface which causes sticking and some "grinding" noise when the friction brakes are used. Cleaning the rotors periodically by putting your Prius in neutral (disables regeneration) at about 25 MPH and lightly applying the brakes (repeat if necessary) will control the symptoms.

    JeffD
     
    #2 jdenenberg, Jul 2, 2014
    rmoon likes this.
  3. Easy Rider

    Easy Rider Active Member

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    Location:
    N. Central Florida
    Vehicle:
    2013 Prius c
    Model:
    Three
    What he said ^^^^^
    In addition, you should give the rotors a close inspection.
    On a vehicle that old, it is possible that the rotors are worn or badly pitted......in which case they will be chewing up the new pads rapidly.
    The "surface rust" that appears on a healthy rotor usually does not cause noises as it is more of a "stain" than actual rust.
     
    #3 Easy Rider, Jul 2, 2014
    rmoon likes this.
  4. rmoon

    rmoon New Member

    Joined:
    Jun 25, 2014
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    Location:
    los angeles, ca
    Vehicle:
    2004 Prius
    Model:
    Three
    Thank you for your advise. Much appreciated
     
    #4 rmoon, Jul 2, 2014
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