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Air in Brake Accumulator

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Tom in Maine, Aug 8, 2016.

  1. Tom in Maine

    Tom in Maine Junior Member

    Joined:
    Mar 14, 2013
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    Location:
    Searsport, Maine
    Vehicle:
    2005 Prius
    Model:
    II
    Got a nice 2005 from Florida. The brake accumulator had to be replaced. We installed a used unit.
    Had a local garage bleed the air from the system with their $7000 Snap On Scantool.
    All the lights are out and the car brakes okay.
    But, upon starting, the accumulator pump comes on and sounds like it is cavitating.
    It stops after about 2 seconds.
    In the interim, I got my hands on a PC with a Mini VCI and Toyota Techstream.
    I have bled the system a couple times but still have this noise.
    Did pick up a pressure bleeder to try to push fluid back through the system and get the air out of the Accumulator. Have not done that yet. Not sure which lines to do and what to actuate.
    At this point, I am cavitating and would appreciate any insights.
    At this point, there are no codes and no lights, just the noise which is intermittent as the brakes are used.

    Tom in Maine
     
    #1 Tom in Maine, Aug 8, 2016
  2. miso03

    miso03 Junior Member

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    Location:
    Bratislava, Slovakia
    Vehicle:
    2006 Prius
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    N/A
    Hi Tom,

    this behavior is perfectly fine, every Prius does it. You can read about it through whole internet. Just keep calm and enjoy new to you Prius ;)
     
    #2 miso03, Aug 9, 2016
  3. Qamar

    Qamar New Member

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    Vehicle:
    2010 Prius
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    Hi Tom,
    I agree with miso03 ,I got accumlater leakge code in my 2010. Checked from multiple mechanics including of toyota's.
    Got air bleed multiple time manually and also from scanner. Then changed accumlater as just bleeding wasn't working.
    Now all lights gone and breake is normal again. But every time step on brake paddle accumlater start making sound with a little vibration.
    I thinks it's normal working of accumlater to do it's job.
    Still testing ,as for the lights don't pop up again and brakes goes abnormal.
     
    #3 Qamar, Oct 8, 2016
  4. Tom in Maine

    Tom in Maine Junior Member

    Joined:
    Mar 14, 2013
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    Location:
    Searsport, Maine
    Vehicle:
    2005 Prius
    Model:
    II
    I seem to have some air stuck in a replacement accumulator.
    No codes, but I would like to clear it if possible.
    Have a spare accumulator but would prefer to not go that route.

    I have been studying the plumbing of the system. I do have Techstream but cannot purge the air with it.
    Been wondering about pressure bleeding by putting pressure on the fluid reservoir and running the pump to push any air out of the accumulator.

    Thanks,
    Tom
     
    #4 Tom in Maine, Nov 10, 2016
  5. JDenyer232

    JDenyer232 Member

    Joined:
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    Location:
    Maine
    Vehicle:
    2016 Prius
    Model:
    Two
    The noise you hear is normal. The accumulator is an air pump that pumps up the pressure in a nitrogen charged tank. On the other side of the tank is the hydraulic fluid. When you open up the car door this pump starts up to get the braking system ready. It sounds like an aquarium air pump when it runs. If you aren't getting any codes and the brakes work fine then you are good to go.
     
    #5 JDenyer232, Nov 10, 2016
  6. valde3

    valde3 Senior Member

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    Why? Have you tried all the different bleeding options in it?
     
    #6 valde3, Nov 11, 2016
  7. Tom in Maine

    Tom in Maine Junior Member

    Joined:
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    Location:
    Searsport, Maine
    Vehicle:
    2005 Prius
    Model:
    II
    I have done all the bleeding options. This is a car that I have sold to a customer. Just trying to make it work as good as possible.
    Have sold a lot of units and none with this kind of noise.
     
    #7 Tom in Maine, Nov 11, 2016
  8. JDenyer232

    JDenyer232 Member

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    Hmm, hard to figure out what's going on without actually hearing it. Any chance that the used replacement accumulator is bad?
     
    #8 JDenyer232, Nov 11, 2016
    valde3 likes this.
  9. douglasjre

    douglasjre Senior Member

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    Location:
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    ----USA----
    Tom:

    What code did you have before replacing accumulator? Did you replace master cylinder too?
     
    #9 douglasjre, Mar 11, 2018
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