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Brake Accumulator Pump Buzz Seems To Be More Frequent Than Usual

Discussion in 'Gen 2 Prius Main Forum' started by Kizzy, Nov 16, 2018.

  1. Kizzy

    Kizzy Member

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    I've just begun to notice that the "buzzing" from the brake accumulator pump on my '08 Prius seems to happen more frequently than usual, or perhaps I'm just noticing it more. So I thought I would ask how often you think is "normal" to be hearing the pump come on? It seems to kick in about every other time I press the brakes. Sometimes also as I'm accelerating after a stop. I could be wrong but I think it used to do it less frequently, like maybe every three or four times on the brakes.

    There have been no warning lights on the dashboard, so I take that as a good sign. I also checked for error codes on the ABS system with Techstream and nothing comes up. So maybe I'm just being paranoid, but I'm hoping for someone to confirm such. :)

    As a side note, I am probably due for new brake pads. So perhaps due to the pads being worn, and the pedal consequently needing to be depressed further to come to a stop than if the pads were new, could be causing the pump to have to reprime the system more often than usual?

    Seems logical to me, but would be curious to hear your sage opinions and advice on the subject.

    Thanks in advance!

    Cheers,
    Kizzy
     
    #1 Kizzy, Nov 16, 2018
  2. kens97uber171

    kens97uber171 Active Member

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    Brakes being worn does not change pedal height like other cars. Fluid level will be lower..
    Make sure when you out new pads on to follow the procedure...
    Or the car can actuate the brakes and pop the Pistons out of the calipers.
    Also.. when you compress the calipers.. it will push fluid back to the reservoir.. if it's too full now.. it can overflow.

    I changed my accumulator this year.. the faster cycling of that pump may be an indication of an issue .. or not.
    Mine got REALLY REALLY bad before I got any warning lights...

    Posted via the PriusChat mobile app.
     
    #2 kens97uber171, Nov 16, 2018
  3. Skibob

    Skibob Senior Member

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    When is the last time the brake fluid was flushed?
     
    #3 Skibob, Nov 16, 2018
  4. John321

    John321 Senior Member

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    I too drive a 2008 Prius. In June of this year I noticed the same symptoms you are having. My brake actuator was running much more frequently. I had no codes showing. A few months later I got the abs vsc brake lights all coming on. It was indeed the brake actuator that was failing and it finally reached the point of no return and began throwing warning lights. I replaced mine. I bought a new brake actuator from Oalthe Toyota for $1134 and installed it myself. I have Techstream software that I used calibrate the brake actuator after install and bleed the brake system. This is an involved repair and there are many wonderful post here on how to do it. I used these posts as well as the factory manual when I did mine to get me through the repair. The Toyota dealership estimated $3,800 for replacement. I live in Kentucky and am sure some areas would be cheaper some more expensive.It took me 7 hours to do the job. From my experience I think you should begin planning for the brake actuator repair. Much better to prepare for this rather than be caught by surprise by this expensive and time consuming repair.

    I do hope yours is not the brake actuator but your description is an almost exact replay of what my car was doing.
     
    #4 John321, Nov 16, 2018
    Last edited: Nov 16, 2018
  5. Kizzy

    Kizzy Member

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    I don't recall ever having the brake fluid flushed. The car has only 50K miles on it (has basically been a short-distance grocery getter its whole life), but I know that despite the low mileage it is overdue for a comprehensive brake inspection and service, and I absolutely plan to do that within the coming week. Do you think flushing the brake fluid (or perhaps bleeding the system) could help make the brake pump need to kick in less?

    I should mention that the car has no problem stopping. The brakes are solid. Other than the brake pump seemingly kicking in more often than usual as of late (again, could be my imagination but don't think so), I have not noticed any problems at all with the brakes.
     
    #5 Kizzy, Nov 16, 2018
    Last edited: Nov 16, 2018
  6. JC91006

    JC91006 Senior Member

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    If you can hear the pump go on while stopped at a light, you probably have an internal leak. I notice my 2005 doing it more
     
    #6 JC91006, Nov 16, 2018
  7. Kizzy

    Kizzy Member

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    I haven't noticed that. It will make the noise as I'm coming to a stop, or sometimes as I'm accelerating out of a stop, but not repeatedly while just sitting at a light with my foot on the brake pedal.
     
    #7 Kizzy, Nov 17, 2018
  8. JC91006

    JC91006 Senior Member

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    So you are probably still good with the actuator. When it starts leaking to the point where you hear it at a stop light, then you'll have to think about a replacement.
     
    #8 JC91006, Nov 17, 2018
  9. Kizzy

    Kizzy Member

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    That's what I was hoping to hear. Thanks for putting my mind at ease! I'll keep an ear out and lislten if it worsens over time.
     
    #9 Kizzy, Nov 17, 2018
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