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2007 Prius - To Flush or Not to Flush Brake Fluid

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by sdrocker, Jul 20, 2018.

  1. sdrocker

    sdrocker Member

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    I read some literature someone else posted regarding how much longer the Dot 3 in a Prius seems to last. I honestly have no clue, I was just about ready to flush and use new Dot 3 but I read from others that this increases the likelihood of causing issues with one of the brake actuators... who's right and wrong here? I'm sure both sides have good arguments. Is the risk of leaving the fluid in there as is higher than the risk of flushing and causing actuator problems? Or is it the opposite where leaving the fluid longer causes the actuator to fail sooner.. No idea.
     
  2. sdrocker

    sdrocker Member

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    True... do you use a particular type of test strip to check the fluid? Or is it something generic from any parts store? I remember there was an article written regarding this topic where a particular type of strip was used (Phoenix??) I can't recall.
     
  3. ChapmanF

    ChapmanF Senior Member

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    You might be thinking of this page by hobbit, which describes the test strips about 1/3 of the way down the page. Those were from Phoenix Systems, as you say. Per his description, they seem to test for dissolved copper, and some evidence was gathered that that's a particularly good test. There may have been earlier/other strips that simply indicated water content. If I buy some, which I probably will at some point, I'll probably go with the Phoenix.

    -Chap
     
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  4. frodoz737

    frodoz737 Top Wrench

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    I suggest both of you consider flushing your brake fluid. "Any car" that has the original brake fluid 8 or 11 years exceeds any service duty cycle. While it's likely neither of you will heed this advise, know this friendly comes from someone who has worked on cars, aircraft and most every common machine out there for decades...and still does. In fact, the safety of the flying public is in my hands every day.

    Respectfully, the question was asked and has been answered.
     
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  5. sdrocker

    sdrocker Member

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    Yes that was the page and article I was referring to. The Phoenix systems strips are $20 for just two of them on ebay. I might be better off just changing the fluid. I already have $43 of Toyota brand Dot 3 sitting on my shelf.
     
  6. sdrocker

    sdrocker Member

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    Hmmmm... well I have $43 of Toyota brand Dot 3 sitting on the shelf. I don't feel like spending $20 for just two of the Phoenix strips. I have the mini VCI techstream tool. I suppose I could just do it... I wanted to get expert opinions on why I should not change the fluid and how it causes brake actuator problems but I don't have a solid feel for why it does.

    Do you have any idea why people claim it causes issues with the actuator? Here's what someone wrote last week in another forum:

    "Brake flush unnecessary. In fact the dealers down here don’t do it as many reports of abs failures because of brake flushing.

    Prius is very very easy on the brakes and the fluid. Regen works really good. It’s not anything like a regular car.

    Yes techstream is the software to use to manipulate the proportioning relays And dot3 fluid is fine."
     
  7. JC91006

    JC91006 Senior Member

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    The car we are talking about here is the Prius, not some super car that requires to stop going 150 mph.

    The pros for changing fluid in a Prius.

    1. The fluid gets changed

    The cons for changing fluid in a Prius

    1. You can contribute to ruining a $1000 part, which the dealer will quote $4000 to fix.

    So you decide which is best for you.
     
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  8. ChapmanF

    ChapmanF Senior Member

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    Same subject just happened to come up recently in another thread: here you go.

    That thread is Gen 3-specific. In Gen 3 it matters to keep the words actuator and accumulator straight, because in Gen 3 those are two separate parts, and the concern is actually the longevity of the accumulator.

    For your Gen 2 the distinction is less important, because you only have one replaceable assembly that combines those two parts.

    That discussion avoids the other issue of possible outright mistakes during the process, like letting air get sucked in while replacing, which can turn a simple procedure into a complicated one. Toyota provides a Techstream procedure for a complete system bleed, but it isn't clear whether even they are convinced it always succeeds. In their Gen 3 recall campaign for the sometimes-failing-too-early accumulator, they had a rule that if any of the nitrogen had already escaped into the actuator, to just unconditionally replace that too, not to try to bleed it.

    -Chap
     
    #28 ChapmanF, Jul 23, 2018
    Last edited: Jul 23, 2018
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  9. frodoz737

    frodoz737 Top Wrench

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    So there you have it. Preventative maintenance, reactive maintenance (wait until it brakes), afraid to do maintenance (I heard it might break) and cheaping out. My signature below says it all...and I earned that "Top Wrench" title by the way.

    I will leave you folks to it now, because this is like an "oil thread"...and I should've known better. Best wishes sdrocker. I further suggest, if not already done, you have the transmission drain and fill and have both coolants replaced. Those are not lifetime fluids either.

    Peace Out. ;)
     
  10. JC91006

    JC91006 Senior Member

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    I think the argument is "if cost is not a factor", you should always replace your brake fluid every 3 years or so. Just as preventive maintenance.
     
  11. qettyz

    qettyz Active Member

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    So, i live at Finland where there is 4 seasons. We change our brake fluids every 2 years. Still even if i live at one season coutry i would follow that. Just to make sure that fluid is good for ABS. Brake fluid change every two years cant be too much but buying few cases of beer is ok for example:)
     
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  12. sdrocker

    sdrocker Member

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    Yea.... I saw that thread. If I follow the procedure carefully and don't let any air get sucked in from the master by checking the fluid routinely during the process... I wonder if I can pull it off. My hesitation is in messing something up that is delicate. I can tear through my old hotrod and mess with small block chevy motors but Prius cars give me a bit of hesitation.
     
  13. sdrocker

    sdrocker Member

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    Makes sense.. on paper, 3 years to replace Dot 3 fluid sounds great. I do it routinely on my old 66' c-10 and my 53' Chevy custom hotrod which has a Ford master cylinder I adapted and installed with my own two hands.... I'm just unsure about this newer stuff with Prius cars.. For instance if I follow the techstream instructions carefully will I be fine? It's not about the cost of the Dot 3 fluid.. I already have $43 of fluid sitting on my shelf... However ruining a $1000 part and having to pay $4000 for Toyota to fix is also not a pleasant thought as JC91006 pointed out.

    By the way I changed the coolant not too long ago when I did the water pump... I have to look at the history of the transmission drain and refill. It was done by the previous owner but not by me since I've had it 3 years now. How often does that need to be replaced?

    Next car I buy will be an older toyota tacoma in ok condition, or i may buy a new crate 350 motor and stick it in my 66 c-10 to make it a daily driver and stick to the really old stuff for the next 5 years despite being only in my mid 30s :)
     
  14. Kenny94945

    Kenny94945 Active Member

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    Flush it!
    Bleed air from the system.

    Flush every 2 or 3 years to minimize the amount of moisture in your brake system.
    Toyota OEM fluid is fine, or use top quality fluid...noting the dry and wet boiling points and DOT rating.

    Following the Toyota maintenance schedule is good practice.

    Yes, you can test with special stripes of paper you soak into the current fluid...but I would just change the fluid instead of testing based on fluid age.
     
  15. JC91006

    JC91006 Senior Member

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    I have not changed any of the fluid on my gen 2 cars in California and I have not noticed any braking issues. . Here are some examples

    1. 2006 with 266k miles
    2. 2005 with 207k miles
    3. 2005 with 211k miles
    4. 2005 with 173k miles

    All working properly with no issues
     
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  16. Mendel Leisk

    Mendel Leisk Senior Member

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    I think it's trickier replacing gen 2 brake fluid. Gen 3 Repair Manual has a specific instruction for changing without Techstream, by just putting the car in "invalid" mode. It is sanctioned. I've done it, no problems.

    Gen 2 OTOH, has only an instruction with Techstream. I'll attach the gen 2 instruction.

    Regarding "to change or not to change": Toyota Canada recommends every 3 years or 48K km's (30K miles), for all their vehicles. Since maybe 2012 model year?

    Maybe ask a dealership how much they'd charge, are they experienced with second gen brake fluid change, and let them know you can supply them with brake fluid; perhaps that'll reduce the cost?

    A typical vehicle, it's $100~200 to have a dealership do it, my experience. A bit of caution: the last pro brake fluid change I had done, they misplaced most of the bleed screw caps, AND managed to leave one rear brake completely inoperative. I'm thinking they had an intern mechanic do it, something like that. A return visit rectified everything, and they did a test drive after.
     

    Attached Files:

  17. sdrocker

    sdrocker Member

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    That's impressive. My 2007 prius has 200k on it right now. I honestly don't think I want to keep this car more than another 2 years..... hmmmmm... I drive about 13k per year.
     
  18. sdrocker

    sdrocker Member

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    Thanks, I had seen those instructions before. They look very long.... I don't know if it's an easy job for a DIY'er or not. I do have the techstream tool. Also I only have four Dot 3 12 FL Oz bottles... I think you said I need two pints? If so maybe I have enough?
     
  19. Mendel Leisk

    Mendel Leisk Senior Member

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    Two pints is a quart, 16x2=32 oz. You have more, at 12x4=48 oz. OTOH I hope I'm not having a brain bubble about the Toyota fluid I got being pints (aka 16 oz and 473 ml): I recently got some Honda brake fluid, and it was 12 oz. of course translated to some incomprehensible ml measure, like everything up here.

    Bottom line: I think you have plenty. For me the big concern would be is this DIYable? It seems like going from 2nd to 3rd gen they smartened up a bit, made the process more friendly and doable.

    It'd be nice to find a DIY video for second gen, before diving in.

    Again, low hanging fruit would be to first price it out, having it done through dealership.
     
  20. sdrocker

    sdrocker Member

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    Thanks... I can call the dealer and find out how much if I use the same Dot 3 they sold me for $43... they might lower the price ... hopefully... I do have the inclination to do things carefully following instructions but what if those instructions have issues to begin with? hmmmm....
     
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