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Bleeding brakes from 2012 Prius with pneumatic bleeder

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Ryan Gallo, Sep 3, 2024 at 8:19 PM.

  1. Ryan Gallo

    Ryan Gallo Junior Member

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    I’m replacing the brake pads and rotors on my 2012 Prius and am going to bleed the brake fluid as well. I purchased a pneumatic brake bleeder from Amazon, linked below, and was wondering if this can be safely used on both the front and back brakes as long as I first put the Prius into INVALID mode?

    I’m mostly worried about the back brakes as I know they have the electronic pump system.

    And I won’t need a friend, right?

    Bleeder:
    EWK 23 Pcs 2L Pneumatic Vacuum Brake Fluid Bleeder Extractor Pump Kit + 1L Refilling Bottle
     
    #1 Ryan Gallo, Sep 3, 2024 at 8:19 PM
  2. MAX2

    MAX2 Member

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    You don't need this.
    Brake bleeding is done by the Prius itself. It re-pressurizes the system with a slight pressure leak.
     
    #2 MAX2, Sep 4, 2024 at 1:32 AM
  3. Ryan Gallo

    Ryan Gallo Junior Member

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    Sorry, I got my terminology mixed up. I’m looking to flush my brake fluid. Not bleed them. Would this kit work well, on the back brakes too?
     
    #3 Ryan Gallo, Sep 4, 2024 at 4:03 AM
    Mendel Leisk likes this.
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    I’ve done a couple of brake fluid replacements so far, using the non-Techstream method (proscribed in Repair Manual). My tools were very rudimentary, no external vacuum used, apart from a baster to initially extract/replace reservoir fluid.

    when doing brakes, specifically when retracting caliper pistons for new pads, I’ve never opened bleed screws, and never had subsequent problems. Brake fluid replacement is worthwhile, but I would leave it for another day, and be careful to do it by the book.

    there’s links in my signature, one for brake fluid change, the other about rear brake drag; both have relevant info. (On a phone turn it landscape to see signatures).
     
    #4 Mendel Leisk, Sep 4, 2024 at 8:34 AM
  5. Ryan Gallo

    Ryan Gallo Junior Member

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    Thanks all. The wheels are off, so I’d really like to flush the brake fluid now. I really just need to know whether it will be safe to use the vacuum pump on all calipers, so long as the car is in invalid mode.

    I read somewhere that failing to put it into invalid mode and trying to flush the brakes could damage the electronic braking system for the rear wheels.
     
    #5 Ryan Gallo, Sep 5, 2024 at 1:15 AM
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Guess I’m saying you don’t have to use suction. OTOH NutzAboutBolts did, in their video.
     
    #6 Mendel Leisk, Sep 5, 2024 at 10:06 AM
  7. Ryan Gallo

    Ryan Gallo Junior Member

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    @Mendel Leisk - Another related question: would it be safe to use the pneumatic vacuum pump on the rear brakes without putting the car into invalid mode - and only disconnecting the 12v battery?

    I've replaced the rotors and pads and the car is still up on jackstands. I would like to avoid turning the car on at all, since I've heard brake fluid sediment from the calipers (which had to be pushed into accommodate the thicker brake pads) could recirculate through the system and cause problems. Now is the time to flush, I figure, but I'd like to do it without powering anything back on.

    I just want to make sure I'm not going to damage the electronic pump by sucking from the rear calipers while its completely off.
     
    #7 Ryan Gallo, Sep 7, 2024 at 3:49 PM
  8. ASRDogman

    ASRDogman Senior Member

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    Yes, you can use a vacuum pump. And if you open the bleeder screw while you screw the
    pucks back in the fluid likely go out the bleeder screw... path of least resistance...
     
    #8 ASRDogman, Sep 7, 2024 at 3:55 PM
  9. Ryan Gallo

    Ryan Gallo Junior Member

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    Thanks - so:

    * car off (native terminal disconnected)
    * not in invalid mode (obviously, it’s off)
    * normal brake flush routine with vacuum pump
     
    #9 Ryan Gallo, Sep 7, 2024 at 4:00 PM
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    I would save the brake fluid for another day, and do it by the book. Bleeding the rear brakes is a walk-in-the-park by the proper method: if you've got someone pressing the brake pedal the rears will continuously pump out fluid, without suction, just a tube pushed over the bleed screw, crack it open, run it to something to catch it. Do close the bleed screw BEFORE assistant releases brake pedal.

    Again, I've been changing brake pads for decades, never touched the bleed screws at the same time.

    There's a link in my signature on rear brakes: you want to be careful with the caliper piston orientation, and ensure it doesn't have a chance to rotate, till you've firmed up the brake pedal. Then take a short drive and test. More info in the link.
     
    #10 Mendel Leisk, Sep 7, 2024 at 4:36 PM
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