Brakes almost unresponsive until ICE engine starts

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by SRQ, Jun 14, 2018.

  1. SRQ

    SRQ Member

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    If my 2008 with 190k miles sits overnight, when I start the car and roll backwards, there is insufficient brake pressure to stop the car until the ICE starts running for a few seconds. It's only a matter of time until I back into someone; what do I need to do to fix this?
     
    #1 SRQ, Jun 14, 2018
  2. bobodaclown

    bobodaclown Member

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    Sounds like a broken parking pawl or not adjusted properly parking brake.

    SM-T700 ?
     
    #2 bobodaclown, Jun 14, 2018
  3. fotomoto

    fotomoto Senior Member

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    When you first open the drivers door, do you hear the usual brake pump sound? Do you have normal brakes when the ICE is on or are they still weak? Do you have any trouble lights?
     
    #3 fotomoto, Jun 14, 2018
  4. SRQ

    SRQ Member

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    Yes when I open the driver's door there seems to be something actuating, although I always thought it was the thermos for the inverter coolant.

    I have normal brakes once the ICE has ran for a little bit.

    No trouble lights.
     
    #4 SRQ, Jun 14, 2018
  5. bisco

    bisco cookie crumbler

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    maybe a leak in the actuator. how is the brake fluid level?
     
    #5 bisco, Jun 14, 2018
  6. bobodaclown

    bobodaclown Member

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    Isn't there a TSB on the brake accumulator?

    Z981 ?
     
    #6 bobodaclown, Jun 14, 2018
  7. bisco

    bisco cookie crumbler

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    expired dec.2017.
     
    #7 bisco, Jun 14, 2018
  8. ChapmanF

    ChapmanF Senior Member

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    The sound when you open the door will be the brake pump. The thermos cycle doesn't begin until you ask the car to start.

    What happens if you open the door, get in, wait for the brake pump to finish, then start the car?

    -Chap
     
    #8 ChapmanF, Jun 14, 2018
  9. SRQ

    SRQ Member

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    I was wonder what that sound was. Makes sense though.

    The brake fluid level is fine; between the lines, a little on the low end. The brake system has have never been serviced, including topping off the fluid or even replacing the pads. As I said, once the ICE starts, the brakes are fine.

    I'll experiment a little more and report back here in a few days. This morning the brake pressure was fine but I wasn't empirically gathering any data on when this happens.
     
    #9 SRQ, Jun 15, 2018
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