Ohleats Brake Fluid Tester Pen with 5 LED Indicators, Universal Car Accessories

It seems to work well, tried it various times, and no difference in outcome. Aside from the battery door (Battery not included, just a heads up) being a bit of a task to remove, it's a good little tool.

Does the job and good price

This is fast and easy to use. Display is bright. Performance and quality in terms of accuracy is hard to measure. It can definitely tell the difference between brand new fluid and water. Those results were exactly as your expect. On my used fluid, the results ranged from 2-4% and I took several tests to conclude the mode reading of 3% was probably fairly accurate. For the price it's a reasonable value even if not professional quality. Battery required is a single AAA, and the re-closable bag is a good place to store both between uses.

I was highly skeptical that I needed one of these in my life. Then I opened up my brake fluid which was supposedly being done at the dealership for the last 3 years and it was green. No not black, green. Yes that's right, the brake fluid was green. I'm talking green like Green Eggs and Ham , yes Sam I am. I threw the test pen into the master cylinder and it said 4%, which I guess is red for dead. This is the easiest thing to use in the world, you click the button unscrew the master cylinder throw the tester into the brake fluid and look for the light. You have a 5 position light that indicates what percent the amount of water in the brake fluid is. Green for go, yellow for warning and red for dead. Looking at the brake fluid you could clearly tell it was very bad so obviously the tester itself is accurate. The build quality seem sufficient for what it is, it does not say it is waterproof so make sure to only immerse the testing probes. I recommend not storing a battery in the pen if you're going to not check anything long term. Oh yeah you need 1 AAA battery that should last forever. Now I'm spending $200 on Amazon for an automatic brake flushing machine so I never have to pay the dealership again. You should too, It'll help the economy.

Seems to work... Caught dealership lying with this.

Me being the skeptic i ordered one. It does actually work.

For good maintenance, I like to follow car manufacturer's recommendations. It was time to flush out OEM brake fluid on my Toyota Tacoma. Used this sensor to see if old fluid was contaminated. It showed a small, minor amount of water contamination. This was good to know. The sensor was easy to use and worked perfectly.

As you can see in my video, it doesn't register 100% tap water as having more than 3% water content so I wouldn't trust it to give you a correct reading with only 3% water in a solution with 97% brake fluid. I was originally planning on doing 4 tests. The first with 100% water, then incrementally add brake fluid and retest with ratios of water to brake fluid of 50/50, 10/90, and finally 1/99. Unfortunately it failed the test at 100% water so I discontinued testing and give it a failing grade. I'm returning the Oleats brake fluid tester due to it being inaccurate and will pick up another one for roughly $5USD more with the hopes it'll be accurate. I'll test it and try to remember to post the results here.