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might be a neat tool but all brake fluid will absorb some moisture and suck up some dirt. i myself always look at the fluid and if its dark i just replace it with new. it never hurts to keep your fluid clean.
How are you going to test the moisture at the calipers? The brake fluid won't be consistent from reservoir down to calipers. It doesn't circulate and mix.
Yep, it measures resistance and probably fairly accurate. I saw one on Amazon for $10 and then the same one from China (where no doubt the one on Amazon was from) for ~$2 free shipping on eBay. Ordered for fun as I thought I would check the fluid as I did the Ranger Method for clutch fluid.
These are the results:
My first drain fluid showed 3% moisture. At 4% requires changing. On the 7th drain it was zero, the same as the new fluid in the container!
Brake fluid is very hygroscopic (picks up water like a sponge!) That moisture will diffuse though the fluid from calipers to reservoir and will NOT be significantly different!
SIDEBAR
The product I received was in an obviously designed for US in a sealed blister pack. All US English no other language. Probably excess from a lot made for a US supplier who paid $1 and sells for $10! The Chinese give free mailing as a way to increase exports! Real fair completion! For me to ship a small item to China in a small Priority Mail Box it cost $35! Crazy.
Yeah my brake fluid after two and a half years and 10k miles showed <1% but the clutch was 4%. I flushed brakes today and had to get a turkey baster today to do the clutch later this evening.
Oh, and I also used it to check a can of brake fluid that I had opened some time back to see if it was ok. It measured zero so I figured it should have been fine.
Yep, it measures resistance and probably fairly accurate. I saw one on Amazon for $10 and then the same one from China (where no doubt the one on Amazon was from) for ~$2 free shipping on eBay. Ordered for fun as I thought I would check the fluid as I did the Ranger Method for clutch fluid.
These are the results:
My first drain fluid showed 3% moisture. At 4% requires changing. On the 7th drain it was zero, the same as the new fluid in the container!
Brake fluid is very hygroscopic (picks up water like a sponge!) That moisture will diffuse though the fluid from calipers to reservoir and will NOT be significantly different!
SIDEBAR
The product I received was in an obviously designed for US in a sealed blister pack. All US English no other language. Probably excess from a lot made for a US supplier who paid $1 and sells for $10! The Chinese give free mailing as a way to increase exports! Real fair completion! For me to ship a small item to China in a small Priority Mail Box it cost $35! Crazy.
Color is NOT a good indicator! You can buy test strips but these meters are cheap and work. Frankly I do the Ranger Method once a year so no need to measure as I do it whatever! I bought the meter because it was so cheap (just checked eBay and saw several for $2.99 free shipping from China!) I wanted to perform those tests when I did the Ranger Method!
GM says the color in the clutch fluid (DOT 4 brake fluid) comes from staining by the seals cause it to turn black quickly (I assume the graphite -or whatever- seals on the throughout bearing. Brake fluid dissolves paint so assume it will pick-up other "stuff" as well.) My color change is from draining the old fluid, putting in new and pumping the clutch 30 times. Repeat that ~7 times. Uses most of the 12 once containers I buy. Like to start with a new container ($4) where there is an unbroken aluminum foil seal on the new container.
The problem with using a brake fluid tester is it might work better if it is calibrated for the type of brake fluid (DOT3 or DOT4) you are using to get proper results. Here is a DOT4 calibrated unit on Amazon:
Brake Fluid moisture tester
