Brake Fluid Liquid Tester Pen,2PCS DOT 3 DOT 4 DOT 5.1 Brake Fluid Liquid Tester Pen, Car Diagnostic Testing Tool with 5 LED Indicators, Hydraulic Fluid Liquid Oil Moisture Analyzer

Simple to use and effective in providing results. Great way to extend the Maintenance Interval on my Tesla Model Y

What this tester tests for is moisture in your brake fluid. This is a cheap tester, but it does a very good job testing for moisture. The size is very small and it can fit in your pocket like a pin the light on it or bright so you shouldn’t have a problem seeing what your test result is it fits a triple AAA battery so the battery life depends on what type of battery you put in it and I honestly would recommend anybody who works on their own cars to have one of these in our toolbox. It’s not like it will break the bank because it’s very cheap but this does work if you put it on anything with water on it, it will go red. I bought this to test my brake fluid and my brake fluid needs to be changed because it has a high moisture level and I would’ve not known, unless I had a tester like this one

This is my second one of these. They work great, easy to use and seem to be accurate. However, you have to be careful not to dip the probes too deep. The plastic will eventually start to crumble. Apparently it is not resistant to brake fluid. Just insert the probes enough to measure and then wipe them dry. My first one lasted a couple of years, but the last time I used it, it was on a vehicle that I couldn't see where the fluid level was and accidentally got it too deep. I dried it off, but some must have entered inside. The next time I used it was a few months later and when I pulled the cap off, the plastic around the tips just came apart. As cheap as they are, I just bought another one. I'll be more careful this time.

It’s supposedly working but where I tested - in the reservoir it showed no water. Brake fluid tends to be worse closer to brakes themselves. Which I didn’t test.

Garbage. Received it in multiple pieces. Shipping box fine and cap still on the tester pen. Pulled cap off and the sensor section under cap was in pieces with one probe detached. Am I going to climb into my diesel truck and drive 30 minutes round trip to return this $6 item... No. What I'm gonna do is learn a lesson and hope you do also. Let my loss be a clear message to you... DO NOT BUY THIS HUNK OF TRASH.

I hesitantly bought this Brake fluid liquid tester to see if it works or a gimmick, and to my surprise, it actually works. My initial test showed that I needed to replace my brake fluids due to water being in the line. So I bled my brakes, retested my brake fluid, and it passed, indicating no water. I am amazed and pleased that it actually works. Saves me a trip to the mechanic shop.

After my mechanic told me my brake fluid needed to be changed, for a nominal fee (haha), I bought this tester and found that my brake fluid was okay... a small price to avoid a larger price for replacing all my brake fluid.

The price was right so I thought that I'd take a chance. It appears to work and I tested it against straight water and then olive oil to be sure. However, after I had my brake fluid changed it still showed 4+percent moisture in the reservoir. I returned to the auto shop and the mechanic and I used it to test the brake fluid straight out of the bottle. It tested fine. Later, I found that if I used a toothpick to push down the floater in the reservoir, it tested fine. If I let this device push down the floater while testing, it registered over 4% moisture. So, I'm not sure if it's a fluke, if I still have a high moisture content or if it's fine.