Click on image for the product link My Rock Auto newsletter landed in my inbox this morning and I was educated on a tool that I have to admit I never knew existed; a brake fluid tester.
Over the years I must have gone through many gallons of brake fluid on my projects and vehicle maintenance in general. While the project bikes get a full fluid replacement as a matter of course, there are cases where more complex systems are not so easy to flush out, like cars or modern ABS-equipped bikes. For those tasks, it would be great to know if the brake fluid does, in fact, need replacement. That's when this tool would pay for itself. Owner's manuals like to suggest a two-year replacement schedule, but that's rarely followed and, in reality, is rarely necessary.
Here's an excerpt from the newsletter's article:
"Brake fluid absorbs water over time or relatively quickly if left exposed to ambient air. Under heavy braking, that water could boil, reducing hydraulic pressure in the brake lines and causing brake fade. Water may also acidify the brake fluid which can lead to internal galvanic corrosion of components in the brake system.
Acidic brake fluid can mimic the electrical properties of battery acid. The voltage of that weak "battery" can be used to approximately measure the moisture content of the brake fluid. Set a multimeter to DC millivolts (mV). Put the positive multimeter lead in the brake fluid in the master cylinder and the negative lead on a good ground or the negative battery terminal. A reading greater than 300 mV may indicate the brake fluid is contaminated with water and should be flushed and replaced with new fluid.
A dedicated brake fluid tester can provide another convenient way to test brake fluid moisture content. Submerge the brake fluid tester's two probes in the master cylinder reservoir. The tester measures conductivity between the probes and translates that data into a moisture reading. Generally less than 2% water is good and more than 3% water means the old brake fluid should be flushed out of the system and replaced. I found the dedicated brake fluid tester to be more accurate than the multimeter.
Another advantage the brake fluid tester has is the ability to test leftover brake fluid in an opened bottle. Leftover Johnsen's brake fluid I had in my garage since 2019 was still good with 0% water contamination. The bottle's lid must have been sealed tightly."
This tool will soon be finding its place in my toolbox, so that I can more accurately decide when my vehicle's fluid needs freshening.
Over the years I must have gone through many gallons of brake fluid on my projects and vehicle maintenance in general. While the project bikes get a full fluid replacement as a matter of course, there are cases where more complex systems are not so easy to flush out, like cars or modern ABS-equipped bikes. For those tasks, it would be great to know if the brake fluid does, in fact, need replacement. That's when this tool would pay for itself. Owner's manuals like to suggest a two-year replacement schedule, but that's rarely followed and, in reality, is rarely necessary.
Here's an excerpt from the newsletter's article:
"Brake fluid absorbs water over time or relatively quickly if left exposed to ambient air. Under heavy braking, that water could boil, reducing hydraulic pressure in the brake lines and causing brake fade. Water may also acidify the brake fluid which can lead to internal galvanic corrosion of components in the brake system.
Acidic brake fluid can mimic the electrical properties of battery acid. The voltage of that weak "battery" can be used to approximately measure the moisture content of the brake fluid. Set a multimeter to DC millivolts (mV). Put the positive multimeter lead in the brake fluid in the master cylinder and the negative lead on a good ground or the negative battery terminal. A reading greater than 300 mV may indicate the brake fluid is contaminated with water and should be flushed and replaced with new fluid.
A dedicated brake fluid tester can provide another convenient way to test brake fluid moisture content. Submerge the brake fluid tester's two probes in the master cylinder reservoir. The tester measures conductivity between the probes and translates that data into a moisture reading. Generally less than 2% water is good and more than 3% water means the old brake fluid should be flushed out of the system and replaced. I found the dedicated brake fluid tester to be more accurate than the multimeter.
Another advantage the brake fluid tester has is the ability to test leftover brake fluid in an opened bottle. Leftover Johnsen's brake fluid I had in my garage since 2019 was still good with 0% water contamination. The bottle's lid must have been sealed tightly."
This tool will soon be finding its place in my toolbox, so that I can more accurately decide when my vehicle's fluid needs freshening.
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