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Loud clunk when braking?

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by Monday, Oct 14, 2015.

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  1. Monday

    Monday Junior Member

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    Hi all,
    I was having some issues with rattling sounds from my brand new (less than 100 miles) Prius C2--see my thread here.

    Well, a whole new problem has surfaced that is much more alarming--every so often when I brake there is a loud "clunk" that comes form the underside of the car. I hear the clunk again when I resume driving from the stop.

    I haven't been able to isolate when this happens--sometimes it's happened when I've braked gently and other times harder. Hills and speed bumps seem to bring it out, but not always. I'm also really trying to baby this car, so please believe me that I am not the type to drive aggressively and then slam on the brakes unless I have to!

    I took it in to the dealership and they could not find nothing wrong. Went for a drive with the tech and could not duplicate the problem.

    I can definitely "feel" the brakes in the Prius more than I could on my old car, even when they're engaging normally, and I'm hoping that's normal. This sound has me really concerned, though, esp. since other threads that discuss it have it cropping up on cars that have thousands of miles on them, not less than 100.

    Thanks for any suggestions you may have!
     
    #1 Monday, Oct 14, 2015
  2. bisco

    bisco cookie crumbler

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    it all sounds very normal to me. keep in mind that prius brakes are very different from a non hybrid. you have initial regeneration from the motor/generator to slow you down, then when necessary, the friction brakes are applied. there is a transition there that can be felt under certain f=driving circumstances.
    add to all that the abs and some uneven road surfaces, and you have a system that can take some getting used to. if you remain uncomfortable, ask the dealer to let you take another one for a good long test drive under varied conditions. all the best!(y)
     
    #2 bisco, Oct 14, 2015
  3. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Could be unrelated to the brakes, say a loose suspension bolt somewhere, makes a noise when you step on the brakes.
     
    #3 Mendel Leisk, Oct 14, 2015
  4. Monday

    Monday Junior Member

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    Thanks for your responses!

    bisco--"normal" is exactly what I want to hear. :) Thanks for that explanation.

    Mendel Leisk--I'm hoping the tech would have checked the suspension bolt, if that might possibly create this sound? I have no idea, not being a car person myself.
     
    #4 Monday, Oct 14, 2015
  5. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    When you're hearing a sound when you're braking, then accelerating you hear the same or similar sounds, it sounds a lot like something loose, with some play.

    Hey: bottle rolling around in the hatch? :ROFLMAO:
     
    #5 Mendel Leisk, Oct 14, 2015
  6. Beachbummm

    Beachbummm Senior Member

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    body in the boot not dead yet?
    muffler bearings?
    neighbors cat wrapped around an axle?
     
    #6 Beachbummm, Oct 14, 2015
  7. orenji

    orenji Senior Member

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    You could be hearing the transition from ICE to EV. This car does not behave or makes sounds like a normal car. What you seem to interprete to be problems sound like normal Prius sounds. You had it looked at and Toyota found no issues, so just drive and enjoy the car. What is the worse that could happen, you are covered under warranty.
     
    #7 orenji, Oct 14, 2015
  8. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    I do not know, suspension collapse at high speed?
     
    #8 Mendel Leisk, Oct 14, 2015
  9. orenji

    orenji Senior Member

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    What would collapse?
     
    #9 orenji, Oct 14, 2015
  10. Monday

    Monday Junior Member

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    Thanks, all.

    It made the sound a couple of times while I was on a drive just now. Both times when I was coming to a gentle stop at a stop sign on completely flat terrain. It just doesn't sound like it is a normal noise that the brakes should be making. Like, if it was a normal sound, it would be a well-known, commonplace occurrence for Prius drivers?

    I had the brakes go out on me in a car when I was a teenager and am super-leery of anything brake-related.

    Honestly, the only thing that might set my mind at ease would be to take a spin in a couple of other Prius C2s and see if they're making these same noises.
     
    #10 Monday, Oct 14, 2015
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