Kia says to flush brake fluid every 4 years?
- Thread starter Klutch9
- Start date
My experience is mainly GM, not much with AISIN. I'll take you word for it Astro!
In GMt400 master cylinders there is a large rubber "diaphragm" which serves as the seal, below the cap. All the way up to 2001 in the C3500HD models. The black thing with the pluses is the part under the cap.
Speaking of brake fluid changing, for my Civic, I bought a Motive pressure bleeding pump and an adapter cap. I found this so much easier to use than a vacuum bleeder.
4WD
$50 site donor 2025
I guess if enough things are correct here: a periodic top change is better than no change - and one can flush whilst doing pads …
The Turkey baster doesn't do a whole lot.
I can scientifically prove otherwise, but I’m always open to new information.
edyvw
$50 site donor 2025
You tested moisture % around pistons?
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.
Still looking over the manual and learning things about our Carnival. The maintenance section recommends flushing the brake fluid every 4 years. It specs DOT 4 LV, aka SL.6, etc. This fluid tends to be slightly more hygroscopic than the older stuff, yet Kia still recommends 4 years. I'm not sure I've had a vehicle that recommended an interval that long. I usually do flushes between 2-3 years, and I'm pretty sure our Explorer, which uses the same fluid, recommends 2 years in the manual (too lazy to check).
New here, not new to vehicle maintenance. Curious why anyone would let their brake or clutch fluid go so long? I flush all my trucks brake lines / reservoirs about every 3 months, but they also see extreme severe duty.
Brake / clutch fluid is cheap. Even the synthetics. Only takes a few minutes to pressure flush the system. A 50 gallon drum of brake fluid lasts a few years, and you get a couple hundred flushes / refills on all your trucks / cars / etc.
As a bonus, the used dirty fluid is fantastic in a waste oil burner. Burns HOT
Hot testing. The pens are better than nothing but not very accurate, years ago we used a device that looked like a miniature hot plate, you small amount of used fluid on and it heated it then gave a reading, they were very expensive. New units are much less expensive and do a good job.
The one from Hazet is pricey but cheaper ones works dare I say just as well and are accurate. Probably worth the money for a commercial brake shop.
https://hausoftools.com/products/ha...Rjr5ZabTVP8FWI37kAhTowZZLk9dP3sHfGpISa-fYW3-3
A good alternative for under $100 and good for a small shop and DIY.
https://www.amazon.com/Precision-De...pcontext&ref_=fplfs&psc=1&smid=A3N6NMITXL6Z86
Yup…bought one. I usually try and make brake fluid changes coincide with a brake job but the Tundra didn’t need brakes until 4 years and 50k miles, however, the moisture content remained acceptable during that time. The RX 350 needed brakes by 2 years and 25k miles and it already had significant moisture in the fluid so I had them change the fluid.
OP, as the owner of a Kia, I’m going to again try and make the brake fluid change coincide with the first brake job but I will also test the fluid for moisture to see if that makes sense to wait that long. It is 2 years old and has 30k miles and my guess is it will need brakes in the next 10k miles or so and no matter what I’ll have them change the brake fluid too.
This is a falsehood
Glycol absorbs water and for a reason, it performs a function of keeping the system dry. When changing the brake fluid you are removing the moisture. If the brake fluid didnt absorb moisture (such as silicon 5 brake fluid) you end up with water in the system and why you RARELY ever see silicon 5 in a consumer vehicle.
edyvw
$50 site donor 2025
This topic comes every few months, and it is filled with posts where people justify themselves their own habits fishing for confirmation bias.
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
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
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
@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
https://www.mazdausa.com/static/manuals/2022/mazda3/contents/07020600.html