Bleeding fluid flush

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by kehyler, Apr 1, 2019.

  1. kehyler

    kehyler Junior Member

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    Hi All,

    I have done this maintenance before on other vehicles, but apparently the gen 3 prius has some oddities with regard to setting diagnostic trouble codes. I have three questions;

    (1) Do these two sources show how to flush the brake fluid?
    Anyone used a Gen3 Youtube process to bleed brakes? | PriusChat


    (2) Can you flush the fluid from the rear brakes by applying the brake pedal with the rear bleeder valve open? (In the video, nutzaboutbolts uses some kind of electric pump, which I don't have.)

    (3) I'll be using valvoline dot 3 & 4 fluid synthetic fluid, any concerns with that?

    Thanks!
     
  2. tankyuong

    tankyuong Senior Member

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    All you have to do is pump the brakes while the bleeder screw is open
     
  3. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    I loosely followed @NutzAboutBolts video, except I did the brakes in the order proscribed in the (attached) Repair Manual excerpt. I didn't use a vacuum source, apart from using a syringe at the beginning to baste (old) fluid out of the reservoir.

    The front brakes are pretty traditional, which makes them labourious and tricky to do. Watch the video carefully, in the split-screen they show the action of pumping the brakes, then quickly opening/closing the bleed screw.

    The rears are easier, in that you can press the brake pedal, then open the bleed screw and let it pump.

    To be on the safe side, I would stick to Toyota DOT3 fluid. The alternate you mention is probably fine, but who knows. I used two pints, fwiw.

    Apologies, neglected to add the attachment earlier.
     
    #3 Mendel Leisk, Apr 1, 2019
    Last edited: Apr 2, 2019
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  4. The Critic

    The Critic Resident Critic

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    I HIGHLY recommend that you do not attempt to flush the brake fluid if you do not have access to Techstream or an equivalent aftermarket scan tool with the automated brake bleed function. If anyone errors are set while following the process described in the video, you will be left with an undriveable car and most shops will want an outrageous amount of money to diagnose and clear the codes.
     
  5. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    @The Critic I respect your opinion; you may well be right, still the attachment I posted is an excerpt from the Repair Manual, specifically for brake bleed without Techstream, involves a chicken-dance. @NutzAboutBolts outlines the procedure in his video as well.

    I followed it, no problems. I think the main thing is, you want to ensure you do not drop out of "invalid mode". The ways this can happen are outlined, and one of them is simply turning a wheel. So yeah, be careful.
     
  6. The Critic

    The Critic Resident Critic

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    From the 5 or 6 of these that I have done, after every brake flush, there will be several stored fault codes related to the process that have to be cleared. Usually it is a pressure-related fault code.

    For that exact reason, I simply cannot recommend performing the brake flush without having access to the proper scan tool. The risk of an inoperable car is too high.

    Perhaps when the car is in ECB invalid mode, some of the detection logic is ignored? I don't know...
     
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  7. NutzAboutBolts

    NutzAboutBolts Senior Member

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    I’m not sure what you did from those 5-6 brake bleed you’ve done to cause the brake issue, but I’ve been driving my Prius without issues.

    The only thing I can see wrong is if you’re doing the brake bleed with the bleeder valve open and accidentally cause the vehicle to get out of the invalid mode. That will cause an issue. Other than that, it’s a closed system, you’re only messing with the bleeder valve opening and closing, and pumping the brakes to push the brake fluids out from the lines.

    It’s basically a conventional brake bleed without techstream, except the rear brakes which is controlled electronically. If you can’t do that, I’d suggest bringing it to the dealership.
     
  8. The Critic

    The Critic Resident Critic

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    I have never done the brake flush using the ECB invalid mode.

    I have always performed the brake flush using the guided function in Techstream or with the Maxisys Elite.
     
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  9. NutzAboutBolts

    NutzAboutBolts Senior Member

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    That is much easier if you have access to that.
     
  10. kehyler

    kehyler Junior Member

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    Just to update this thread, I appear to have successfully flushed my brake fluid.
     
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  11. kehyler

    kehyler Junior Member

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    I know I did not take your advice, but I appreciated you giving all the less. It heightened my sensitivity to prevent exiting invalid mode.
     
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  12. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    Yeah the one sneaky one is turning a wheel, supposedly will kick you out of invalid mode.

    I did the brake fluid change in invalid mode, 2.5 years back, no problems. Will do it again this fall.
     
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