1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Add brake fluid

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by jason petter, Apr 25, 2015.

  1. jason petter

    jason petter Junior Member

    Joined:
    Sep 30, 2012
    13
    1
    0
    Vehicle:
    2012 Prius
    Model:
    Three
    I have question for add brake fluid, are there any techniques to add on the brake fluid? Or just open the cap and pour it in? I searched online, they told do not shake the break fluid before pour in to vehicle because the air bubbles…etc. and discard unused or old break fluid. Thank you
     
  2. NutzAboutBolts

    NutzAboutBolts Senior Member

    Joined:
    Mar 5, 2013
    1,476
    1,551
    0
    Location:
    Bay Area
    Vehicle:
    2012 Prius
    Model:
    Four
    its simple as just putting in the brake fluid... not sure how the bubble would reach the brake lines if you already have fluids in the reservoir...
     
  3. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,270
    15,068
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV


    You haven't mentioned why you're thinking of adding brake fluid. Do you have a leak, or have you done work on the brakes that caused fluid loss?

    The brake reservoir has a min and max line. The only time you should ever see the fluid near the max line is when (a) brand new pads have been put on at all 4 wheels, and (b) the brakes have been pumped with electric power off until hard, so all the fluid from the pressure accumulator is back in the reservoir.

    Any other time, the fluid level should not be at max. As soon as the booster pump wakes up it uses some of the fluid to fill the accumulator, and as pads wear, more fluid goes to the calipers. If you add fluid under those conditions, you will have too much.

    If it is comfortably above min and you're not losing any, you're good. If you're losing any, you need to fix the leak, not just add fluid.

    -Chap
     
    CR94 likes this.
  4. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,662
    38,207
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    ^ what he said. Unless you've got a leak, no reason to add fluid. Level will drop as pads wear, and likely return to top mark with install of new pads.