Prestone max dot 3 brake fluid

[Chevy454z71]

How can Prestone claim 100,000 mile fluid life?

 

[Oro_O]

The exact same way automakers say that ATF is “lifetime.”

 

[zrxkawboy]

How? Well, the stock brake fluid lasts the life of the vehicle in the vast majority of vehicles, and that is usually well over 100k miles.

 

[E150GT]

It doesn't disappear. It still works after 100k. I'm sure they aren't saying it performs as new after 100k though.

 

[zray1]

Even in systems that are sealed, DOT 3 , 4 and 5.1 will absorb moisture . I can’t explain how it happens, but seeing the results is plain enough. Changing brake fluid every 2 or 3 years will keep the system much happier

 

[Chevy454z71]

Even in systems that are sealed, DOT 3 , 4 and 5.1 will absorb moisture . I can’t explain how it happens, but seeing the results is plain enough. Changing brake fluid every 2 or 3 years will keep the system much happier

That’s why I think it’s crazy they say 100,000 miles, how much moisture is that brake fluid going to have in it/all that moisture I think would cause pistons to seize and damage to abs units and maybe even brake fade/failure.

 

[zray1]

My service experience has primarily been with poorly maintained antique and vintage cars and motorcycles. Seals in the Master cylinder, caliper, and drum cylinder often look fine but they are shot, letting in air before they show signs of leaking fluid.

Z

 

[E150GT]

I bet a vast majority of cars with 100k on the road have original brake fluid in them. I can tell you the brake fluid in my 2016 is

 

[zray1]

highly accurate testers for moisture in brake fluid are only about $20 on Amazon, consumer grade can be had for $10 or less.

It’s easy to check for moisture, and then one will know for sure the level of contamination.

When I check it’s not uncommon for the moisture levels to be significantly different at the M/C , front calipers, and rear calipers / cylinders.

Z

 

[Chevy454z71]

highly accurate testers for moisture in brake fluid are only about $20 on Amazon, consumer grade can be had for $10 or less.

It’s easy to check for moisture, and then one will know for sure the level of contamination.

When I check it’s not uncommon for the moisture levels to be significantly different at the M/C , front calipers, and rear calipers / cylinders.

Z

Why do you think that is? I would think it would all have the same level. Where is it the highest and lowest moisture level?

 

[zray1]

Why do you think that is? I would think it would all have the same level. Where is it the highest and lowest moisture level?

I don’t know the cause, likely just a difference in seals integrity from one location to another. As the master cylinder fluid was often worse off, it could be related to just removing the cap to check or add fluid.

Unused fluid in a bottle that has only been opened once or twice will also show moisture contamination.

 

[Chevy454z71]

I don’t know the cause, likely just a difference in seals integrity from one location to another. As the master cylinder fluid was often worse off, it could be related to just removing the cap to check or add fluid.

Unused fluid in a bottle that has only been opened once or twice will also show moisture contamination.

What tester do you use?

 

[zray1]

What tester do you use?

Mine looks similar to this one, just an older version.

Brake Fluid Tester, High Precision Car Brake Fluid Detector, Hydraulic Fluid/Liquid/Oil Moisture Analyzer with LCD Screen Audible Alarm DOT3 DOT4 DOT5.1 Tester https://a.co/d/egkduXf

 

[willbur]

What tester do you use?

Just use a VOM set on mv dc scale. IIRC, less than 0.3 mv is ok

 

[KGMtech]

I've found the inexpensive BF testers on Amazon can be iffy - like much of their site. Did my BF 1 week ago in my Infiniti and the tester showed my brand new just opened bottle of KleenFlo DOT3 was at 1% water. Doubt it. FWIW the old stuff I drained was at 3% water for 30 months of use in SW Ontario per this same tester.