Can I bleed brakes old fashion way?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by hendr1x, Dec 20, 2025 at 3:54 PM.

  1. hendr1x

    hendr1x Junior Member

    Joined:
    May 24, 2024
    22
    6
    2
    Location:
    US
    Vehicle:
    2011 Prius
    Model:
    N/A
    My 2011 Prius had the rear brake lines disconnected (changed rear axle beam) so there is air in there but I don't think there is a lot but I have to get it out. I reconnected them each quickly but it happened twice. During removal and installation. I figured I would also do the front and do a full fluid flush.

    Anyway...can someone confirm I can just bleed my brakes the old fashion way with someone pumping on the brake pedal with my battery disconnect. My battery has been disconnected since I started this job and computer has no codes currently. I'd rather not go through the process of invalid mode....never mind spending money on techstream.
     
  2. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    27,649
    18,246
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    The dependable answer is no. Only with a scan tool can you trigger the opening of various valves in the actuator that are otherwise closed and create dead ends that cannot be bled.

    If you're very sure the only air that entered the system is still localized back near the rear brakes, you might be able to succeed in bleeding air just from those lines, without a scan tool. That would be a specialized exception to the general rule. There's no guarantee you'll get away with it.

    You can't do it by pumping the pedal with the battery disconnected. That only uses the fail-safe hydraulic system, which doesn't include the rear brakes. So the system has to be powered. When it is powered, with a steady pressure on the pedal, you don't have to pump; pressurized fluid will come out the bleeder as long as you have it open (or until the reservoir is drained and air is sucked in up front).

    Without being in the bleed procedure or in invalid mode, though, that excess fluid flow is likely to trigger a trouble code that will leave that line valved off.
     
  3. PriusCamper

    PriusCamper Senior Member

    Joined:
    Mar 3, 2012
    12,786
    5,178
    0
    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    I've talked to several people who have successfully bled the brakes the old fashion way, even when replacing brake booster pump. But when I go down this rabbit hole I intend to use an Autel device's bleed procedure and if that doesn't do the final calibration I'll use Toyota Techstream on an old laptop.
     
  4. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    13,023
    2,332
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    If you had the rear disconnected at the beam? Fill the reservoir up I'm assuming you let it empty fill it up go to rest of car wait for fluid to come it is coming. Wen it do spin one caliper on bleeder open rt side . Go left add caliper close it's bleeder . Let rt side drip 20 minutes . Close same on left side . Whaddya ya got? No pumping .
     
  5. hendr1x

    hendr1x Junior Member

    Joined:
    May 24, 2024
    22
    6
    2
    Location:
    US
    Vehicle:
    2011 Prius
    Model:
    N/A
    If I have to start the car to bleed the brakes I assume I'm going to get errors in the system. Is that going to screw me. I read a lot people warn about errors that can't be cleared except by the dealer. Is that a concern for me?


    @Tombukt2 I assume that is gravity bleeding? I'll look into that. I didn't empty anything. I just separated the lines and immediately reattached...twice at each junction.

    @PriusCamper : But to bleed the brakes they had to put the car into invalid mode?

    @ChapmanF : Thanks for explaining, I didn't realize that is how it worked.
     
  6. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    27,649
    18,246
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Not 'start'. Just power to the brake system (what we often call "IG ON").

    You don't get errors if you are using a scan tool to make the bleeding happen, or if you enter ECB Invalid Mode first, using a jumper wire.

    If you enter ECB Invalid Mode using a scan tool, you do get a code (C1451) that can only be cleared with a scan tool—by going through the bleed procedure, which is what you're there for anyway, so that shouldn't be a deal-breaker.
     
  7. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    13,023
    2,332
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Yep gravity fills up whole actuator from mid feed to bottom and top of the aluminum block do fluid get in front and behind those opening valves that are not yet . I've lotsa issues with brake bleeding not happening no matter the scanner . Fails on first screen alot Park brake set ign on or ready and so on . Push next and fails fire it starts . But vehicles scan fine 8 can clear all take info etc do other things but not bleed . Had happened 4 times 4 different vehicles battling one today .
     
  8. Mendel Leisk

    Mendel Leisk MMX GEN III

    Joined:
    Oct 17, 2010
    60,307
    41,493
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    It’s not that hard.