Brake Fluid Liquid Tester Pen with 5 LED Indicators, Calibrated For DOT3 DOT4 Brake Fluid

Except for the battery cover which needs some scotch tape to stay put (!!), this is indeed a very reliable and accurate brake fluid tester, and surprisingly so. Looking at the poor snap lock design of the battery cover I did not have high hopes for the rest of this device under $15. I was indeed very surprised by its accuracy to exactly measure water content in brake fluid, which is its intended purpose. I ran multiple calibrated tests with new and 3-year old brake fluid all stored in tightly sealed containers. Took exactly 5mL brake fluid samples each time being very careful in handling the sample so the sample's glass beaker was totally dry and any sample transfer syringe was also totally dry. Tested to a baseline of 0% water content. Added a drop of tap water into the brake fluid sample and thoroughly mixed it. A drop of water is generally 0.05mL, so achieves 1% water content with a drop of water added. It read exactly 1% on the tester! Then added another drop, thoroughly mixed it and tested, and it read 2% water content! Added another drop of water likewise and it read 3% water content! Added yet another drop (the 4th drop) and it read 4% water content, all as they should appear! The sensors are calibrated to be highly sensitive and accurate. Probably the only purchase I can ever recall less than $15 that is so darn accurate. Now if you all (nice manufacturer in China though they may appear German to some based on the German words on the tester) will only fix that battery cover so the AAA battery does not pop out during a test without scotch tape on it, you will really have an all-round superlative winner, and not desperately try to pass as German quality. I also looked at the brake fluid boiling point testers which are much more expensive and cover a wider range of brake fluids. Those are touted to be the most accurate. Question really is if those are even necessary for the most common every-day use with such a low cost and highly accurate electrical conductance tester available. Ultimately the boiling point of brake fluid is inversely related to its water content, and electrical conductance infers the water content based on known conductance testing references.

Works great, I used it on two cars, a 2022 truck, and a 2011 car. On the truck the device did not detect any water. On the 2011 car it did detect water, suggested to change the fluid, which i did. Highly recommend this product.

I bought this ITEQ Brake Fluid Tester to add to my garage toolkit, and it has already paid for itself. It’s incredibly simple to use—just dip the prongs into the master cylinder, hit the button, and the LED lights instantly tell you the moisture level in your brake fluid. ​It takes all the guesswork out of knowing when it's actually time for a fluid flush. The build quality feels solid for a pen-style tester, and it's small enough to keep right in the glove box or tool tray. Highly recommend for any DIYer who wants to stay on top of their vehicle's safety maintenance!

Works just about as expected. Just wished that it came with a battery & battery holder (for when the device is being stored for a long time between uses). Also wished that the cap was tethered to the rest of the device; my clumsy self dropped the cap into the engine bay within seconds of use, so I had to 3D print a replacement cap. Just some easy fixes to elevate the product without greatly increasing production cost that I think the design engineer should have considered.

Seems like a quality and easy to use product to check for moisture in your brake fluid. I live in Arizona so moisture isn’t a huge problem here.

Defective not too happy with this. First off this is my own fault. I should've spent way more time reading the reviews. The warning signs were already out there. And I even sent back three bottles of brake fluid to Amazon because everything brand new is testing to effective. And I bought three separate bottles at my local store and they tested defective. Oddly enough, I had an older bottle of brake fluid that tested in the OK range. Makes no sense. Just like all the car parts that we buy anymore. Nothing is built with quality anymore. So along no quality control automotive parts for our vehicles. We also have defective automotive parts and fluids detectors that are defective. I'm passing my window for returning. It's not the cost that bothers me. It's the fact that someone even can sell this. My advice to anyone purchasing this is before the return window is up. You better check it first and check it on multiple things. Check your neighbors cars if you have to. Make sure that it works. Is there ever gonna be a day again in America, where when we put an automotive part in our vehicle, it actually works like it's supposed to. And if we buy tools to test things, the tools are also going to be proper and work? This is absolutely disgusting. No wonder the younger generation doesn't want to work on any vehicles.

Update June 2023: (There is an interesting video review of this tester, indicating abnormally high contamination levels in various samples of new brake fluid. The test appears to use a nearby bottle of ionized electrolyte drinking water in an effort to decontaminate the tester's probes between measurements. The ionized water could have a concentration of ions thousands of times greater than that of the contaminating water in the brake fluid. Microscopic amounts of the ionized water, shedding off the probe tips into the brake fluid samples, could be enough to alter the outcome of the conductance tests. It would be interesting to see that test rerun, with de-ionized water used to clean the probes, in lieu of the ionized water.) Original Review: While I don't have the resources to conduct an exhaustive evaluation, I was able to test the unit to my satisfaction. I started by testing the DOT 4 brake fluid in two high performance automobiles. The testing was performed by completely immersing the unit's probes into the master cylinders. Both vehicles had a brake fluid flush less than a year ago. Before immersing the tester, I switched the tester ON and verified that its green battery check light illuminated. For both vehicles, the tester showed a single yellow light, indicating water contamination of less than one percent. After bringing the tester indoors, I tried to approximate the tester's accuracy using various concentrations of tap and distilled water. When immersed in undiluted DISTILLED water, the tester illuminated only the battery check light (the expected result). When immersed in undiluted TAP water, the tester showed all of the lights, indicating water contamination greater than 4 percent (also expected). When immersed in a mixture of one part tap water and 19 parts distilled water (5 percent), the tester showed the expected result of greater than 4 percent. When immersed in a mixture of one part tap water and 39 parts distilled water (2.5 percent), the tester correctly extinguished the >4 percent LED, showing <3 percent contamination. Based on my evaluation, I have confidence in the levels reported by this tester. However, I'll add a few notes of caution: My testing showed only the contamination of fluid in the brake fluid reservoir. Unlike other automotive fluids, the brake fluid doesn't circulate, and the lack of contamination in one part of the system does not prove a lack of contamination in other parts. In my opinion, to measure the contamination with any degree of confidence, a sample of fluid from each of the brake calipers would need to be extracted and tested. Also, a part of my fairly unscientific testing was done at room temperature, and another part with only a single type of brake fluid. I've yet to determine the tester's consistency over its specified temperature range, or with other brake fluids.

Great little tester, and it is accurate. I just flushed and filled the brake fluid in my boat trailer, so I used this in the reservoir and it showed 0% moisture content which is accurate as all of the fluid had been replaced. I then used it in my truck reservoir which needs some love, and sure enough it shot all the way up. I hate to admit but I am behind on replacing the brake fluid in my truck. Flush your brake fluid every time you do a brake job! Don't be like me and put it off. Get yourself a one person brake bleeder, takes less than 15 minutes for good peace of mind.

Muy fácil de usar, para uso personal está excelente, para un taller usaría uno mejor. Por el precio vale la pena.

Esse produto informa, com uma certa precisão, o momento em que o fluído de freio deve ser substituído.

Worked as advertised. It proved that my brake fluid was perfect, no reason to replaca all with all the work of bleeding brakes etc. I now only topped-up my brake fuid reservoir with a little fresh brake oil. So an immediate payback here.

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Usage: - you must clean the probes every time before you submerge the tips into the brake fluid reservoir for an accurate reading I tested against: 1) 3yr old car with 40,000 km on fluid (green) 2) 11yr old car with 140,000km on fluid (red) 3) Classic vehicle with unknown years and km (red) 4) Classic motorcycle with 18yr old brake fluid (red) 5) Previously opened bottle of brake fluid (Castrol LMA) with good cap (yellow) 6) Another previously opened bottle of brake fluid (ATE) with good cap (green) 7) Very old bottle of brake fluid with broken cap (red) 8) Water (4% red) 9 Distilled water (3% red) Pros: - green, yellow, red LEDs easy to understand - easy to read in the dark - appears to be accurate - inexpensive Cons: - green LED bleed into other LEDs which makes it look like all the LEDs are glowing green at first - battery door is hard to open by hand and I predict the plastic tab will eventually wear down At this price, it's hard to complain. Great product! Note: Amazon says battery not included and this is the case even though the package on the back says included.