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Weird burping noise when braking

Discussion in 'Gen 3 Prius Main Forum' started by DerBuchster, Dec 11, 2010.

  1. DerBuchster

    DerBuchster New Member

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    My 2010 Prius has been making a weird grunt or burp when I stop. I thought it was the anti-lock brakes being oversensitive, but it happens so often now that I can't believe that's true. I live in San Diego and it is NOT wet here. I mentioned this problem when I had my first oil change and the dealer said they had never heard of this issue.

    The noise goes away sometimes, but comes back if I do anything other than come to a gentle, slow stop. Now it has started happening even when I am applying the brakes while cornering. It has also changed from a single grunt to a couple of coughing sounds sometimes.

    That alarmed me, so when I took it in for its 10K service. I asked the dealer to test drive it. They can't have actually done the test drive because I was easily able to produce the noise again on the way home!! They claimed that the noise was due to a nut on one of my wheels that fell off because they failed to tighten it properly when they rotated my tires. NOT. It has been intermittently making this noise since it had less than 1000 miles.

    What the *&# is causing this sound?
     
    #1 DerBuchster, Dec 11, 2010
  2. 32kcolors

    32kcolors Senior Member

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    Are you familiar with what regenerative braking sounds like?
     
    #2 32kcolors, Dec 11, 2010
  3. DerBuchster

    DerBuchster New Member

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    I also own a 2005 Prius, so yes, I am extremely familiar with regen brakes. This is a very loud grunt. When it first happened, I was alarmed, so I visited this forum and decided that maybe it wasn't a big deal. But then I drove a loaner 2010 Prius identical to my own while my 2005 was in for service, and it didn't make this noise.

    It used to occur only when at or near a complete stop. It was also a single noise. But now it has started occurring as I corner and has changed. Sometimes it is now a cough - cough, as well.

    Frankly, if Toyota designed a brake system that makes this kind of a sound under normal operating circumstances, I would be astounded.
     
    #3 DerBuchster, Dec 11, 2010
  4. 32kcolors

    32kcolors Senior Member

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    Doesn't sound normal. Next time, be inside the car with the technician when they take it for a test drive. That's the only way to ensure they hear the sound.
     
    #4 32kcolors, Dec 11, 2010
  5. DerBuchster

    DerBuchster New Member

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    This morning it made the sound when I applied the brake BEFORE I even started the car!
     
    #5 DerBuchster, Dec 12, 2010
  6. jdenenberg

    jdenenberg EE Professor

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    The Brake "Bark" is a known problem in 2004-2007 Prii (do a search). There was a TSB (TSB BR001-07) covering it. The noise is generated by air bubbles in the hydraulic fluid going through the brake "Actuator" that is mounted on the firewall (passenger side). It was eliminated in my 2004 by bleeding the passenger front brake, but in some cases (where the actuator is letting air in) you need a new actuator (???).

    I have not heard of this problem in later Prii, but it could occur.

    JeffD
     
    #6 jdenenberg, Dec 12, 2010
  7. wagdaddy

    wagdaddy Plugin Ready!!!

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    Mine's doing it too. Exact same thing. It's not all the time, just when I press the brakes with some force. It pretty much does it all the time when I activate the brake assist.
     
    #7 wagdaddy, Dec 13, 2010
  8. DerBuchster

    DerBuchster New Member

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    Thank you so much, JeffD! I think that this might be the source of the problem. I will post back again if it is resolved by bleeding the brakes/replacing the actuator. Weird that this problem would be identified and addressed, but then reappear in a later Prius model.
     
    #8 DerBuchster, Dec 13, 2010
  9. Eoin

    Eoin Active Member

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    My 2010 also makes this sound when I brake fairly hard. My 2005 is fine. Should I mention it when I take it in for the free 15,000 mile service?
     
    #9 Eoin, Dec 13, 2010
  10. Fstr911

    Fstr911 Member

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    #10 Fstr911, Dec 13, 2010
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