OEM Brake Fluid Intervals vs. ATF Intervals

Don't put words in my mouth or assume anything about me. I said nothing about what I do. I do brake fluid exchanges, own a Mityvac tool, and my preferred brake fluid is Pentosin LV.
I am talking in general that it is absolutely ridiculous to have discussion about whether there is a need to flush brake fluid. And of all things, we are talking most important safety feature that is dirt cheap to keep running properly.
 
This is a "Guess" on my part, but it could be that with all the sensors in the braking system any amount of water above a certain % may cause problems by bringing rust into play. This % may be quite small, but as I said it's a guess. My MB required it every 2 years and my Lexus every 3.
Not just water, it also gets contaminated with copper and other metals and becomes corrosive. Sure you probably could ignore brake fluid changes just like transmission fluid but don't come crying to me when in 10-15 years your brake lines are rusted out, calipers and wheel cylinders frozen etc.
 
I tend to change my brake fluids every 3 years and just recently got a fluid tester as well. Have never got a reading past the first notch. Does that mean it's safe to extend my fluid change intervals?
 
No. Read post above. It is other contaminants that are present too.

If it's a tester that measures the conductivity of the brake fluid, the other contaminants (metal ions) will increase the conductivity of the brake fluid. These testers fail the brake fluid when it is too conductive.

A refractometer brake fluid tester can only measure how much water is in the brake fluid.

So it depends on what kind of tester is being used.
 
@edyvw How do you know flatlanders ride their brakes? Just curious. Perhaps define "flatlanders"?
Regarding @The Critic geography, yes there are mountains around here; the Sierra Nevada and the Santa Cruz ranges.
But as compared to the majestic Rocky Mountains, they are mere dirt mounds.

And then there are regen brakers like me who barely use our brakes; they will easily last 100K.
All good.

By the way, I do brake fluid and ATF services.
 
@edyvw How do you know flatlanders ride their brakes? Just curious. Perhaps define "flatlanders"?
Regarding @The Critic geography, yes there are mountains around here; the Sierra Nevada and the Santa Cruz ranges.
But as compared to the majestic Rocky Mountains, they are mere dirt mounds.

And then there are regen brakers like me who barely use our brakes; they will easily last 100K.
All good.

By the way, I do brake fluid and ATF services.
Bcs. I can read license plates.
 
I'm thinking that the lifetime transmission fluid accomplishes two things: lower cost of maintenance for the first owner and it also discourages the quick lube places and DIYers from messing up the transmission by servicing it incorrectly.
Yep, let the dealership service the transmission incorrectly.
 
I have no idea why our Lexus GS350 F Sport has "lifetime" ATF while Aisin, who made the transmission, recommends services.
Oh yeah, Lexus does not define "lifetime", so there's that...
By the way, after servicing brake fluid, I always get a better pedal. Placebo? Perhaps. Piece of mind? Absolutely.

I had the same nonsense with an 08 BMW 3 Series and my 17 Outback. None of the manufacturers actually define "lifetime." I don't fret brake fluid changes by the manual. I end up doing brake fluid at the time of brake/rotor replacement. I live in a rather hilly area and summers see high humidity July and August.

Just me but I see the owners manual recommendations from two lenses. Lens 1 is will I sell/trade at anypoint under 100k miles? If so, I would only do oil changes at the specified mileage in the manual. If I'm keeping it past 100k, and I almost always do, I believe what you do maintenance-wise in the first 100k sets up the next 100k. The manual does not address my needs as the consumer holding a vehicle long term mileage wise.

You're scaring me Jeff!!! I have the same bizarre feeling I have a "better" pedal after a brake fluid change.
 
I understand most cars in Japan get ATF D/F service every 40K km which is less than 30K mi. I stick with 30K mi D/F sched myself regardless car make.
As far as BF - I do it every 30K mi as well, regardless.
 
I have not seen a car crash attributed to 'lack of BF changes' but I still change mine at 30 month intervals because it's not difficult or expensive and it goes with the meme of BITOG membership. Ditto for transmission fluid changes.
 
I have not seen a car crash attributed to 'lack of BF changes' but I still change mine at 30 month intervals because it's not difficult or expensive and it goes with the meme of BITOG membership. Ditto for transmission fluid changes.
Brake fluid can impact longevity of calipers. One caliper that has issues can contribute to problems on slick surface etc. No one puts on forehead: “i had accident bcs. brake fluid.” Add to that master cylinder and other components.
But in Europe, you won’t be able to register car if fluid is older than 2 years, and there is a reason for that.
 
I understand most cars in Japan get ATF D/F service every 40K km which is less than 30K mi. I stick with 30K mi D/F sched myself regardless car make.
As far as BF - I do it every 30K mi as well, regardless.
Japanese cars in Europe are running ACEA C3 oils, here they run 0W16 water.
 
I have had 2 calipers fail from lack of maintenance by previous owners. One was a slight pull while driving the other one I lost all brakes while driving. Many don't change it and have no issues but its not something I will put off, stopping is more important than going.
 
Most Japanese automakers are requiring brake fluid changes every 2-3 years and these vehicles are using DOT3. I have tested several vehicles with original DOT3 brake fluid after 10 years and moisture reads
On the other hand, transmission fluid changes are commonly lifetime fill with the exception of Honda.

Why are OEM's considering brake fluid services to be essential, but not transmission fluid? I have always considered brake fluid replacement to be a "nice to do" item, but hardly mandatory....especially since it can open a real can of worms for people living in the rust belt.
An honest question, where are you measuring the moisture? At the master cylinder reservoir, the slave, or the mix after a flush?

An observation, the fluid near the slave gets hot, and no organic fluid is immune to chemical breakdown.
 
An honest question, where are you measuring the moisture? At the master cylinder reservoir, the slave, or the mix after a flush?

An observation, the fluid near the slave gets hot, and no organic fluid is immune to chemical breakdown.
At the master.
 
I was about to change pads and rotors until I flushed my brake fluid, and it felt night and day. I'm sure its mostly air but the fluid came out pee yellow and the new stuff was clear. Sure the brakes probably could work fine for many years, but I brought confidence back into my brakes and deleted the dead travel space. ATF on the other hand, I wouldn't leave longer than 60k with factory fluid for longevity. Of course OEMs don't want you to touch anything until you're off warranty.
 
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