Brake fluid change and ac

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by EazyPeazy, Jun 3, 2020.

  1. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Where to do the test? Would results maybe vary, between from the reservoir vs at a bleed screw?

    10 year old car, I’d do it. @NutzAboutBolts has a helpful video. Takes about an hour and 2 pints of Toyota DOT3 will do, around $15.

    Addendum: 4th gen Repair Manual brake fluid change (with/without Techstream) info added. Reading through, I see the order (sim to 3rd gen) is:
    F/R, F/L, R/L, R/R

    Note also, while RM doesn't mention, it's good to baste out and replace most of the brake fluid in the reservoir at the outset, to jump-start the replacement. @NutzAboutBolts does this too.
     

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    #41 Mendel Leisk, Feb 26, 2021
    Last edited: Feb 26, 2021
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  2. PriusII&C

    PriusII&C Member

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    @Mendel Leisk: Hobbit did it at both the reservoir and the bleeder. Both show no degradation.

    Changing brake fluid on my Gen 3 is not a big deal because of @NutzAboutBolts' video to follow. My concern is my Prius C (model two). I have not seen any detailed description on how to do it without the Toyota scantool.
     
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  3. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Ah. I don't have Prius c RM pdf, maybe won't exist till someone get's subscrption and cobbles one; I think they quit making pdf and print versions as of 2012. You could get the shortest perscription length ($20 USD), at Toyota Tech Info, and double-check if there's a non-Techstream method. Download and make pdf's and share if you can. :)
     
  4. PriusII&C

    PriusII&C Member

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    Thanks.
     
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  5. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    I see a one month base subscription is $90 USD. I'm somewhat tempted to go for that, and download away, the merry plagiarist, the Prius c and v. Maybe if-and-when 5th gen Prius rolls out, 3 birds with one stone.

    Maybe someone has some tips? Would appreciate PM on how to. I'd especially like to know if there's someway to rework the links so they'd work in an off-line pdf version. Have full Acrobat if it matters.
     
  6. ChapmanF

    ChapmanF Senior Member

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    Yeah, I think the general assumption is the darkest and disgustingest fluid will be what's out at the cylinders, but if you've got a pack of cheap test strips, no reason not to dip both. And you learn stuff. And if you post what you learn then PriusChat learns stuff. (Especially if you find, say, that you've got a higher contaminant level than hobbit or I had at comparable miles, and we can start trying to puzzle out what made the difference.)

    There's always the alternative to go ahead and flush everything Just Because. It will give you peace of mind and feel virtuous, but you won't learn stuff (including whether that way of spending your afternoon was worth not doing the other stuff you could have spent it doing).

    Or you could have your eye off the ball during flushing for just that one moment that the reservoir gets low and a gulp of air gets sucked in, and then you're either using Techstream's long-form bleed procedure to get that sorted again, or asking yourself "great, have I got a paddle that works in this kind of creek?".
     
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  7. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    That possibility kept me completely on the the ball, the couple of times I DIY’d, using non-Techstream method.

    FWIW, Toyota Canada recommends tri-yearly or 48k kms for this.
     
  8. PriusII&C

    PriusII&C Member

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    What is the reason to put the car in "invalid" mode @NutzAboutBolts' video? What happens if one just does it as if it were a regular car?

    Any comments on the following video where the car is off? No need to keep pumping for the front brakes either.
     
  9. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    All I know is you’re supposed to put it in Invalid Mode, and it’s doable. I really wouldn’t want to tempt fate.

    One gotcha for getting into that mode: parking brake HAS to be on. Also, to shift from Park to Neutral, you have to have brake pedal depressed.
     
  10. ChapmanF

    ChapmanF Senior Member

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    During the replacement you're going to be relying on the brake computer to run the pump, open solenoid valves for you, and not notice large amounts of fluid escaping and declare a massive leak. Invalid mode sedates it so you can do that.
     
  11. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    In the couple of times I’ve done the non-Techstream method I didn’t hear any whirring sounds. I’d speculate if you’ve introduced air into the pumps (say due to replacement), then you need to be using the Techstream method.
     
  12. ChapmanF

    ChapmanF Senior Member

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    I'm not sure why you didn't notice sounds, but you are relying on the pump when you do the rear lines in the non-Techstream method.

    pump.png

    There is just the one pump in a Gen 3. Gen 4 is where the diagram got extra weird with plural pumps.
     
  13. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Hang on, you’re right about that. You can depress and hold brake pedal steadily when bleeding the rears; pump whirs away.
     
  14. PriusII&C

    PriusII&C Member

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    But in the Youtube video I linked above, the bleeding was done with car off. I assume that the car was not in the invalid mode. It looks as he was working on a regular car except continuously pressing the brake paddle.
     
  15. PriusII&C

    PriusII&C Member

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  16. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Hand. Pretty obscure. And, rather than just say the procedure, and the order, in plain English, they repeat the procedure paragraph four times, with each instance changing just the acronym.

    For the record, the sequence is:

    Front right
    Front left
    Rear left
    Rear right

    This is as outlined in 3rd and 4th gen repair manuals.


    To put the car in invalid mode you make it “on”. This is two pushes of start button WITHOUT foot on brake. Ensure parking brake is set, and do the chicken dance.

    It’s easy to do, and the proscribed non-Techstream method.
     
    #56 Mendel Leisk, Feb 27, 2021
    Last edited: Feb 27, 2021
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  17. PriusII&C

    PriusII&C Member

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    Curious about the sequence. I would have started with Rear Right, the further from the reservoir.
     
  18. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    That’s from Toyota; see no point to second guessing. FWIW @NutzAboutBolts starts with rears too.

    if you’re on the fence, wouldn’t hurt to check a few dealerships too, see what they’d charge. Should be $100~150.

    I found 2 pints of Toyota DOT3 to be a reasonable amount when DIY’ing. Baste out and replace about 1/2 cup from reservoir, then try to spread the remaining on all 4 corners, and end up with an ounce or two, just in case you want to fine tune level later. Try to get level where it was beforehand is best I think.
     
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  19. ChapmanF

    ChapmanF Senior Member

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    When the car is off, all the valves in the system are set thus:

    off.png

    and what's open gets bled/replaced, and what isn't doesn't. Any flow you get to the rears in this case still depends on pressure in the accumulator, and the brake ECU is still watching that; the guy in the video even mentions you can hear the pump run to make up the pressure. (The brake ECU is never off even when the car is, as you'll notice any time you open the driver's door in the morning and hear it pump things up to get ready for you.) The guy only demonstrated a little bit of bleeding, nothing like replacing a pint of old fluid, and in his video he got away with it before the ECU said "schezbzflat! where is all that fluid going?!".

    The main caveat with youtube videos is some of them are posted by people who know what they're doing and some, well, aren't, and there is no youtube feature that tells you which ones are which.

    But the sad rule of thumb is that the ones with problems are often the majority. It comes down to the simple fact that a lot of people doing a job will find the manual, look up how it's done, do it competently, not have much problem with it, and not feel any pressing need to go post a video about it. Their thinking goes "what would I be adding? I just looked up the procedure and did that and it worked, isn't that what anybody else would do?"

    By contrast, people who have skipped looking the stuff up, or have convinced themselves they've figured everything out by thinking about it a little, or have had to improvise their way out of some difficulty they self-inflicted by starting from misconceptions, are often inordinately proud of somehow managing to get through it anyway, and feel the world needs to know how they did it, and boom, there's another video on youtube.

    Of course that doesn't mean there are no good technical youtube videos out there. Most around here know Prof. Kelly's Weber Auto videos, for example. I recently saw there's a technical channel from Toyota with good stuff on it. And there's a lot of other good stuff.

    But there's still this kind of psychological natural law that explains why there is so much to sift through on the way to finding the good stuff. One good sign, as a rule of thumb, would be if you find a video that starts by explaining how Toyota said to do something, and then maybe points out a specific difficulty you could run into, and suggests a way around that, and explains how it's consistent with the information from Toyota.

    On the other hand, when you find a video like this one, where the guy's basic argument for taking his shortcut is some handwaving about how the prescribed method is "kind of complicated and confusing" with "a lot of steps and, you know, a lot of focus required" and that's the reason you should just do the thing he guesses might be ok instead ... pass. :)
     
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  20. PriusII&C

    PriusII&C Member

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    @ChapmanF, thank you for the explanation. The method used in the Youtube here has a limitation on how much fluid can be pumped out before the ECU will shut the process down. On the other hand, the "invalid" mode employed @NutzAboutBolts does not have this limitation. Correct?

    RJParker commented in @NutzAboutBolts' video: "Toyota warns: Do not depress the brake pedal to operate the brake booster pump more than 100 seconds at a time. When performing the procedure continuously, release the brake pedal to stop the brake booster pump operating and depress the brake pedal again. Otherwise the system will set codes and disable invalid mode." Does this imply that there is also a limitation with the invalid mode?

    Just try to make sure I understand it correctly.
     
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