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Clicking when foot is on brake & stopped

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by bk2049, Nov 10, 2022.

  1. bk2049

    bk2049 Junior Member

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    Looking for help diagnosing the reason that I'm getting fairly faint clicking sounds when I'm braking. I can't tell where it's coming from but sounds like front driver side of the car. Think it's been going on for a while but I'm not sure. I just started noticing it more lately. When I'm at a complete stop and press the brake harder, the clicks seem to stop. Typically they're every couple of seconds. Thanks for any help!
     
    #1 bk2049, Nov 10, 2022
    Last edited: Nov 10, 2022
  2. ChapmanF

    ChapmanF Senior Member

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    Does that mean you need both things (complete stop, and press harder) for the clicks to stop? So, if you're not pressing harder, the clicks do continue every couple seconds while at a complete stop?

    Sometimes a brake system can have a small leak. It doesn't have to be an external leak, with fluid dripping out from somewhere, though it can be. A lot of the leaks can be internal, say one of the small valves inside the actuator, and the fluid never leaves the system, just returns to the reservoir.

    The brake ECU is trying to hold fluid pressure in the brake lines at a certain target pressure, based on how hard you are pressing the pedal. If there is a small leak allowing the pressure to slowly drop, the ECU can need to click a valve briefly open every so often to send more fluid down that line and keep the pressure up. That makes kind of a repeating clicking, maybe even better described as thumping, noise. I don't know if that's anything like the sound you're hearing.

    If that is what's happening, you may also be hearing the short wind-up-toy or joy-buzzer sound of the brake pump, once every several thumps or so.
     
    #2 ChapmanF, Nov 10, 2022
  3. bk2049

    bk2049 Junior Member

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    Thanks for the response. Yes, to stop the clicks I need to be at a complete stop and push the brake hard. If I'm only pushing it lightly I get the clicks probably every 2 seconds. They're pretty faint. I have not heard anything that sounds like thumping. I absolutely can't describe sounds but I also sometimes get a deeper sound that lasts for a couple of seconds when I push hard on the break once stopped. Not sure if that's the "joy-buzzer" you're referring to.
     
    #3 bk2049, Nov 11, 2022
  4. ChapmanF

    ChapmanF Senior Member

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    Sometimes a recording is worth a thousand words.
     
    #4 ChapmanF, Nov 11, 2022
    Grit likes this.
  5. bk2049

    bk2049 Junior Member

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    Sorry for the delay. Here's a video. The audio isn't as good as I had hoped, but you can hear the faint clicks. When I recorded it happened to be the only time that the light (stability control warning) came on after I pushed hard to stop the clicking---that's the beep you hear toward the end.



    Here's another
     
    #5 bk2049, Dec 1, 2022
    Last edited: Dec 1, 2022
  6. nate358

    nate358 Junior Member

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    It sounds like it could be coming from the brake Booster.... Try going on the outside of the car, lift the hood, and listen for the sound back by the firewall on the drivers side...it would be behind the brake fluid reservoir.

    Posted via the PriusChat mobile app.
     
    #6 nate358, Jan 15, 2023
  7. bk2049

    bk2049 Junior Member

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    Thanks, Nate.
     
    #7 bk2049, Jan 19, 2023
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