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Brakes makes "pssst" sound when applied

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Mixanoid, Jan 14, 2014.

  1. Mixanoid

    Mixanoid Junior Member

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    Hello i have a question: when physical brakes applied (at the end of the slight braking, or when speed is small, or when gasoline engine starts on parking car, or when i apply brakes on parking) i hear light "pssst" sound. It is like sound from back door stay assembly, when i open back door, or like suspension shock adsorber works. My local service bleed the brake fluid, but it doesn't help. When we bleeding rear brakes (left and right) and opens bleeding plug, that noise sounds continiously until we close bleeding plug. And there is no air in old brake fluid... Technican says, that sound is normal, but i also have Toyoyta Prius 20 and there is no noise while pressing brake pedal... I just want to ask: is that soud normal for Prius 30 or not?

    Sorry for my bad english...
     
    #1 Mixanoid, Jan 14, 2014
  2. bisco

    bisco cookie crumbler

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    welcome to priuschat! i don't think you can bleed the brakes without the special toyota software. you might have to take it to a dealer. is the pedal spongy at all?
     
    #2 bisco, Jan 14, 2014
  3. nh7o

    nh7o Off grid since 1980

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    From your description, I would say no, that is not normal. You should hear the pump in the brake actuator run, which sounds like a small motor. But "psssst" sounds like a leak, maybe in the brake actuator itself. How well do the brakes work? Good stopping power? If no warnings on the dashboard, then no worries for now.

    Welcome to PC, and your English is good.
     
    #3 nh7o, Jan 14, 2014
  4. Mixanoid

    Mixanoid Junior Member

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    The pedal is like in my 20 prius, but in 20 brakes seems like... sharper or quickier...
    I bleed the brakis with special toyota software. The dealer says "do not worry be happy" but you know...i live in Russia, dealers here do not worrying about clients.
     
    #4 Mixanoid, Jan 14, 2014
  5. nh7o

    nh7o Off grid since 1980

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    The brake control system has a very deep level of self testing and error reporting. It would not be a simple matter to attempt a repair without having definite error codes shown. You would be spending time and money for an uncertain result. I think that is what is meant by "no worries". I would only suggest that if you can use a stethoscope to locate the exact noise source, then you would be able to make a better decision.
     
    #5 nh7o, Jan 14, 2014
  6. Mixanoid

    Mixanoid Junior Member

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    Scanner does not show any errors in brake system. I just worrying cause the brakes is my life and health. Brakes must works perfect. Not just works somehow. It must works exactly as it must. And that "pssst" makes me not happy. I will use stethoscope or my wife's ears :) to find the noise source, thakx nh7o for tip.
     
    #6 Mixanoid, Jan 14, 2014
  7. nh7o

    nh7o Off grid since 1980

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    I understand about the safety issue. In the Prius, there are three modes for the brakes to work. There is first regeneration, then the assisted friction braking. If those two systems fail, there is still mechanical, direct connection from the pedal to the master cylinder which requires more force, but will still make braking possible. It seems to be a very reliable system.
     
    #7 nh7o, Jan 14, 2014
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