I have tried two different electronic brake fluid testers with Dot 3 fluid and found them both to provide incorrect readings with new fluid registering 1.5 or higher percentage of water. Seems unlikely new, unopened bottles of Dot 3 would read that high but I was wondering if DMS has one I could use to double check against and perhaps if folks have any feedback on electronic brake fluid test devices.
This guy did a pretty thorough test process on his particular model (for some weird reason he doesn’t seem to document or tell what make/model it is, though):
tl;dr: it worked well for him.
That’s one of the models I tried; consistently reads Hi, assuming that the multiple bottles of Dot 3 fluid I purchased new locally should read < 1%
I was looking into alternative approaches and found this item which may be what I’m experiencing.
There are 2 common tools used to test brake fluid. One is a conductivity tester, the other is a boiling point tester.
Bendix does not recommend using a conductivity tester as they have been known to fail when testing freshly opened brake fluid. Conductivity testers estimate the moisture content by converting the conductivity into an estimated boiling point. Since brake fluids vary from formula to formula, this test is not an accurate result unless the tester is calibrated to the manufacturer’s product when new.
Bendix recommends a tester that heats the brake fluid to determine the correct boiling point. Using a boiling point tester is the only accurate way to test brake fluid performance.
This is the cheapest boiling point tester I see on Amazon. No reviews but looks decent.
https://smile.amazon.com/gp/product/B09WHSDRSG/ref=sw_img_1?smid=A1VCW0Y348GQAN&psc=1
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I don’r think DMS has one.
Why would one be needed if the brake fluid / brake system is maintained and flushed every few years?
I use Alfred Teeves Super Blue in my fleet and change it every few years depending on the car.
I normally like to measure and then act rather than follow a set schedule. E.g. “replace fluid every x months regardless of it’s status” isn’t terribly efficient. If it isn’t broken don’t fix it …
You aren’t one of “those” car owners that only adds engine oil when the oil warning light illuminates on the instrument panel are you?
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Not Liqui Moly!? Have you repented? An apostate? Taken leave of your senses?
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LIqui Moly and Motul are my preferred Oils yes…
ATE for brake fluid.- even though the idiots in our DOT banned the “blue” brake fluid that I use in my fleet.
LOL, nope. Even lightly driven over the requisite time period the oil always looks dirty enough to need changing!
Brake fluid though is interesting; can look brand new at the specified interval, hence the testing query. And yes, brake test strips are another way to go!
I disagree on the oil - in a petrol engine…at least not for my experience.
My Diesels are completely different of course. Black engine oil is the norm shortly after a new change with filter.