Kia says to flush brake fluid every 4 years?

[The Critic]

@slacktide_bitog

See below. They say to test and replace as needed, or something along those lines. So Toyota seems to believe in the scientific method instead of just a set time or mileage. Most dealers you Google are 2-3 years.

https://support.toyota.com/s/article/How-often-do-I-need-t-7743?language=en_US

Lexus vehicles have it listed as a required maintenance item every 3 years or 30

What is the Gold Standard for brake fluid testing devices?
Or at least the best of the best for a consumer>

Probably the test strips, which measures the effectiveness of the corrosion inhibitors. I am
not convinced that moisture is an issue with modern brake systems.

This is Prestone DOT3 Max fluid after 3 years:

 

[csandste]

When I replaced front pads on my '17 Soul, since given to my daughter, the Meineke guy used a test strip, declared my fluid good to go and said fluid replacement was mostly a money maker.

 

[John105]

I turkey baste the reservoir annually, pressure bleed flush whenever I do brakes.

I use this on 2/3 cars

https://a.co/d/6d4IQ8Z

The reason is it is perfectly sized to extract one reservoir, and zero chance of spilling or of any backwash.

I get that it’s a lazy way when I have Motive adapters for Toyota and GM, but Dot 3 is $5.98/qt. Cheap enough to do 4x per car per year.

The BMW I bleed each caliper every 2 years.

This is from this AM on the Lexus. It’s more amber maybe due to light. Sometimes it’s clear.

 

[slacktide_bitog]

Kinda false. Subaru recommends every 2. It's in the maintenance manual. I don't think my Toyota does. But it recommends inspecting the fluid. And, logically speaking, why would you inspect something if you weren't going to fix the issue if there was an issue? So while I couldn't find it explicitly stating to replace the fluid, it wouldn't make sense to inspect it if replacement wasn't the result of finding it was bad.

@slacktide_bitog and Mazda. So, I searched for 3 random Japanese brands and they all seem to list fluid replacement. I'll stop now, but I'm noticing a different pattern than you mention.

https://www.mazdausa.com/static/manuals/2022/mazda3/contents/07020600.html

@slacktide_bitog

See below. They say to test and replace as needed, or something along those lines. So Toyota seems to believe in the scientific method instead of just a set time or mileage. Most dealers you Google are 2-3 years.

https://support.toyota.com/s/article/How-often-do-I-need-t-7743?language=en_US

There's at least one more. Subaru says brake fluid every 3 years/30K and technically it should be changed every 15K in high humidity areas.

I did not know that!

 

[edyvw]

Kinda false. Subaru recommends every 2. It's in the maintenance manual. I don't think my Toyota does. But it recommends inspecting the fluid. And, logically speaking, why would you inspect something if you weren't going to fix the issue if there was an issue? So while I couldn't find it explicitly stating to replace the fluid, it wouldn't make sense to inspect it if replacement wasn't the result of finding it was bad.

Toyota likes more Lexus drivers than poor people who buy Toyota, bcs. in Lexus, they do recommend brake fluid flush

 

[4WD]

Toyota likes more Lexus drivers than poor people who buy Toyota, bcs. in Lexus, they do recommend brake fluid flush

New meaning of Car Care …

 

[E150GT]

Every two years. In the spring

 

[yowps3]

I'm all for fresh fluids, but sometimes with brakes and coolant changes, you run the possibility of introducing air into the system which results in a worse situation than just leaving the factory fill in there.

 

[slacktide_bitog]

I'm all for fresh fluids, but sometimes with brakes and coolant changes, you run the possibility of introducing air into the system which results in a worse situation than just leaving the factory fill in there.

for the brake fluid, speed bleeders are awesome

for the coolant, the Lisle coolant funnel is awesome

 

[vavavroom]

Bosch suggests a 3-year service interval for ES6I DOT4. Maybe there are some other extended service DOT4 fluids with longer service intervals out there. Brake fluid is cheap. I replace it every two years or so when the car needs new pads.

 

[vavavroom]

That seems crazy to me. Nobody does that. Even at four years, most owners won't do it.

Ever seen a Bell curve?

 

[HowAboutThis]

I turkey baste the reservoir annually, pressure bleed flush whenever I do brakes.

I vaguely remember that brake fluid doesn't really mix. So this method might not do much as the nasty fluid filled with crud is near the bleeders, from my experience. Unless you're doing brakes and bleeding every 2-4 years.

 

[brandon9715]

I don’t know of anyone that changes brake fluid at all. I keep up on things because I’m picky about maintenance, but I would say there are lots of vehicles on the road with OEM fill that’s 20+ years old.

 

[DemoFly]

I vaguely remember that brake fluid doesn't really mix. So this method might not do much as the nasty fluid filled with crud is near the bleeders, from my experience. Unless you're doing brakes and bleeding every 2-4 years.

I don't baste it with the intention of it mixing. It doesn't have to. Brake fluid is hygroscopic. I also don't care about appreciably effecting water content near the calipers. I care about the seals in the master cylinder and ABS module.

 

[edyvw]

I don't baste it with the intention of it mixing. It doesn't have to. Brake fluid is hygroscopic. I also don't care about appreciably effecting water content near the calipers. I care about the seals in the master cylinder and ABS module.

Thank God there are no seals elsewhere but master cylinder. You don’t care about moisture levels close to calipers? At the point where actually boiling point matters ?

 

[DemoFly]

Thank God there are no seals elsewhere but master cylinder. You don’t care about moisture levels close to calipers? At the point where actually boiling point matters ?

Calipers are cheap and easy to replace. Changed as SOP long before a failure anyway. I don't have a water contamination worry, regardless. I pressure bleed with every pad replacement. No clue why you are so upset about less than a dollars worth of brake fluid.

 

[edyvw]

Calipers are cheap and easy to replace. Changed as SOP long before a failure anyway. I don't have a water contamination worry, regardless. I pressure bleed with every pad replacement. No clue why you are so upset about less than a dollars worth of brake fluid.

In not upset about fluid. I am not talking about water contamination. I am talking moisture levels that can lead to air pocket due to low boiling point.
I cannot remember how many times it has being said here, moisture gets into brake fluid through porous brake lines, not just through fluid reservoir.

 

[Mechanician]

A current recall on Hyundai and Kia is due to a leak in the ABS module. Seals in the ABS can start to leak fluid onto the circuit board, and cause a fire.
https://www.pbs.org/newshour/nation...th-a-dangerous-defect-most-remain-on-the-road

They say it's due to dirt or moisture in the fluid.
So it may be a good idea to err on the side of caution.

"Both companies also said dealers will fix brake fluid leaks found during inspections. Fluid can leak if O-ring seals lose strength when exposed to moisture or dirt in the fluid, according to Hyundai documents filed with NHTSA. If the brake fluid level drops significantly, Hyundai said, the driver would see a warning light."

 

[The Critic]

In not upset about fluid. I am not talking about water contamination. I am talking moisture levels that can lead to air pocket due to low boiling point.
I cannot remember how many times it has being said here, moisture gets into brake fluid through porous brake lines, not just through fluid reservoir.

I don’t believe moisture to be a legitimate issue anymore. Systems are well sealed. I think corrosion, due to depletion of the additive pack, is a bigger concern.

 

[edyvw]

I don’t believe moisture to be a legitimate issue anymore. Systems are well sealed. I think corrosion, due to depletion of the additive pack, is a bigger concern.

Systems are well sealed. But microscopic pores still exist in rubber hoses.
If people think that is not the case, they should change fluid go to local track, and do it with same fluid after 6 months.