Does Brake fluid ever need a flushing?

Any fluid can be contaminated generally the fluid in the Prius brake system is pretty isolated never changes color so it's pretty stout stuff I run.4 in all of my generation twos without any consequence there are test strips you can use in brake fluid to see moisture content pH in general how good a condition the brake fluid is in without somebody just telling you we think so on Why do they think that The fluid turning black dark brown they think there's a lot of water in it because why? And so on It's easy for me as a car guy to tell somebody that doesn't know much yeah you should probably change your brake fluid I can sell all kinds of things all day long doing these things course I'm not usually looking for the extra work but still but there's just a lot of times no need I have brake fluid that's 20 years old and several generation twos It passes the smell test it passes the strip test the brakes work great I'm not fooling with them until I think something is very old or about to break personally but yeah brake fluid it does get bad with time and exposure if it's got lots of time and no exposure been in a sealed canister sealed system so on for all of its time It's probably fine You can crack a bleed screw farther down the line let it all run down until it almost clears the reservoir then pour your new stuff on top of that The new stuff you just poured on top of that will push the old right out of the bleeder screw that's open and then the few tenths of an ounce that are left in the other three lines can be cracked and let that fall out too then bleed the brakes and you should be good .

 

Brake fluid degrades some over time, and can also pick up minor "debris" that result from normal brake system operation.

Periodic brake fluid replacement is a good idea. Some car brands recommend 3 years or 30k, while others say 5 years or 60k.

A few have no interval for brake fluid at all - keeps "cost of ownership" lower (at least in the short term) if you don't do fluid changes and such.

Me, I "flush" the brake system every 3-4 years. Basically pressure bleed the system (using a capable scantool as part of the procedure) until I've pushed a couple quarts of fresh fluid through the system.

I also drain and refill the transmission every 60k as well.

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If you ever had to replace the actuator, that is almost 100% flush . Buy a brake fluid tester (it is really cheap) and you can get an idea of the current condition of the fluid at the reservoir level.

You can use the blue (i think ATE) fluid to make sure that new fluid is in the system in full. With regular fluid, the color change is very close and hard to know when it is replaced completely.

What i learned is, DOT 4 degrades faster, the moisture content goes to 2-3% within 2-3 years here in North Dallas, TX area. DOT 3 goes may be 3-4 years.

 

I alternate between the blue and regular stuff, so I have an indicator when the old stuff is out of the line. I do a full systems flush every 5 years, even if it test OK - start testing at 3 years.

 

Toyota Canada recommends to replace brake fluid, every 3 years or 48k kms (roughly 30k miles). No need for contamination, just a routine change, like oil or coolant. Toyota USA says nothing on the subject.

2nd Gen Repair Manual doesn't have a non-Techstream instruction, so I'd be inclined to go to a dealership for that, unless the guy can demonstrate he's experienced with it.

I have DIY'd our 3rd Gen/s, but it's repair manual does include a non-Techstream instruction. I think there's a link in my signature about the Gen 3 procedure (on a phone turn it landscape to see signatures).

 

Yes; I remember reading a Honda or VW manual that stated 3 year changes also, but without the mileage requirement - I believe. Since I buy, repair, and sell cars as a hobby; I've seen plenty of 10+ year old cars with it's original OEM brake fluid - never changed. I flush out their system and check the brakes while I'm at it - car braking is much improved. The brakes simply fade very slowly, so owners/drivers don't really notice the longer stopping distances required over time. That is until the hit something!!
It's a built-in engineering design to prevent total brake failure. That doesn't mean someone should ignore basic maintenance, but most people do - because they still have some braking ability.

Enjoy:

 

3 years or 30k miles (whichever comes first) is Toyota USA recommendation, for more in-depth brake inspection (not the usual "visual" inspection). It definitely doesn't jump out at you, in the Warranty and Maintenance Booklet.

 

You might want to explain a little better what "capable" means in this context. For the OP, it means that the odds are nearly 100% that whatever scan tool/dongle you currently own will not be able to complete a bleed of the Prius brake system. The Autel AP200 can, and it is probably the least expensive device/software combination that will do this entire procedure beginning to end. I'm sure many of the very expensive tools used by professional mechanics can do this too, but very few of us own one of those.

 

A dealership will charge maybe $150 to do this?

Again, I’ve DIY’d my 3rd Gen, but there is an official non-Techstream brake fluid replacement procedure for that.