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Should I change 17 y/o brake fluid

Discussion in 'Gen 2 Prius Main Forum' started by nancytheprius, Apr 11, 2024.

  1. nancytheprius

    nancytheprius Active Member

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    Just moved from Midwest to soCal. Brake fluid is original to 2006 Prius with 119k miles. Should I get the brake fluid changed at this point? Will new fluid worsen brake actuator like new trans fluid on a traditional ICE car if replaced too late?

    Need input


    iPhone ?
     
  2. Tombukt2

    Tombukt2 Senior Member

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    Yes but you don't have to do anything too crazy undo one of the fittings on the reservoir output over there on the passenger side of the car and bring the level and the reservoir down to almost nothing You see it disappearing in the connection for the lowest tube for output now clamp off that last hose that the fluid is just beginning to run out of clamp it off clamp off the other two disconnect the reservoir take it out of the car and clean it Wash it with soap and water whatever it is you do doesn't really matter You don't want to damage the plastic with super heavy crazy cleaners treat it like a plastic cup or mug Dawn will do or install a new one whatever trips your trigger once that's all cleaned renewed nice dry return it to the car He can put the three tubes on the three fittings on the jug that feed the components over on the driver side of the car now what I usually do is maybe unconventional I go to one of the front wheels and crack the zerk bleed fitting so fluid is now dripping out of that zerk fitting while I'm doing this so fluid is leaving the tube in the reservoir that you left some fluid in going through the actuator and coming out that one fitting so now I wait about 10 or 12 minutes and that should start moving the fluid that was in that tube that we left fluid in You should start seeing it run down if you try and look down the tube you might see it there's a lot lower than it was we'd like it to get all the way to the actuator when we think this sort of thing is happening then we can fill the clean reservoir up with dot four brake fluid all the way up to where the cap goes You're going to bleed it down and let it run down to the full mark this is going to take a while. If you don't like that methodology because old fluid is going to be in a few of the tubes going to the wheels that you don't have open you can manually bleed the brakes like you used to do except on the Prius you start in the front first pumping pumping pumping holding assistant cracks squirts repeat boring I know but it'll move the fluid quickly You can't take on any air now because the reservoir is full The clamps are undone and every time you pump fluid out of one of the wheel fittings that much more fluid is starting to leave the reservoir so you go around to each wheel and do the open and closing about 10 times per wheel and you should be at new fluid at the zerk fitting which is what you're undoing and closing and then that will net you new fluid through the actuator to the wheels and you're good there could be some old fluid still in the master cylinder the part that actually is connected to the pedal but it won't be much to talk about and eventually it will somewhat be mixed with the other You're talking probably less than an ounce of fluid mixed with that whole reservoir of new fluids so there's always that certainly this will outlast the car and your time together for sure.
     
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  3. PriusCamper

    PriusCamper Senior Member

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    I'd wait till 20 years, personally... Lol

    Or more to the point 50 years ago the short lifespan of your car could be dramatically extended by changing all the fluids often, but not so much these days.

    What's more, there's a theory on here that may be true, which is that your super expensive brake booster pump can experience just enough changes during a fluid change that it will fail soon after. This probably has more to do with the mechanic doing the job than the pump itself, but definitely something to consider.

    I'd like to know what @ChapmanF says about how a mechanic could possibly damage a really old brake booster pump doing a fluid change? How much of a risk is that?
     
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  4. ColoradoBoo

    ColoradoBoo Senior Member

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    I'm uncomfortable going more than 5-years.

    But you can do a test on the fuid that's in there with test strips. I'm guessing you'll want to get it changed out ASAP afterwards.

    So I guess we can't upload links or pictures...search on Amazon for:

    Phoenix Systems 8006-B Double-Ended Brake Fluid + Coolant Test Strips (15 foil wrapped test strips), 1 Pack
     
  5. nancytheprius

    nancytheprius Active Member

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    I got the test strip and the strip didn’t change colors. Not sure if my brake fluid is just too far gone or if the strip was defective
     
  6. ColoradoBoo

    ColoradoBoo Senior Member

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    Really? I test both my Tundra (which I just did a brake fluid flush and fill) and my wife's 2017 Prius and got good readings with both coolant and brake fluid. Did you use the correct ends that are marked?
     
  7. nancytheprius

    nancytheprius Active Member

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    Yes! The coolant showed up and tested okay but not the brake fluid!
     
  8. Mendel Leisk

    Mendel Leisk Luddite

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    Toyota Canada recommends 3 years or 48k kms, whichever comes first. Toyota USA doesn't say anything.
     
  9. nancytheprius

    nancytheprius Active Member

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    What does Toyota Canada recommend when it’s been 17 years and you haven’t touched it yet haha
     
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  10. Tombukt2

    Tombukt2 Senior Member

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    Actually if it's clear in the reservoir and everything looks good not turning black or brown it's probably fine I have 26-year-old pure silicone purple silicone brake fluid in a AE something one of the first A engine Corollas I can't remember what year 80 something and that fluid is still purple the brake still work The car somewhat runs We haven't done anything with it in a long time but I move it around the property when needed and the brakes are fine of course silicone won't eat up rubber and turn black or do any of that It's not also the proper brake fluid for the car. One of these days in a yard car I'm going to try the same fluid in a Prius probably with pretty uneventful results.
     
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  11. qmanqman

    qmanqman Active Member

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    You change brake fluid?
     
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