PTE Brake Fluid Tester - calibrated for DOT 4 Brake fluids

This started when my dealer said “Hey! You need bring in your car for an oil change and to flush the brake fluid.” NOTE: my car is still under warranty, which includes all service; so I brought my car in because it was something I did not have to do myself this time. Anyway, I am also one of those people who does most of the service when I can. I admit, I am kind of old school and never flush the brake fluid out unless it’s dirty or smells bad. With that said, I came across this nifty gadget. Basically, you turn it on and dip the leads into the brake fluid and it immediately provides a break fluid reading. It lets you know the condition of your brake fluid – if it needs to be changed or not. Obviously, this brake fluid tester provides a more accurate reading than looks or smell, and for the $7 you cant beat this tester that simply works. If your one of those people who does not work on your own car and you have to rely upon someone being honest, this is a good idea for you too. It really is simply to use. Like I said, unscrew your brake fluid reservoir (which is under the hood), turn the tester on, and dip it into the fluid; you will have an instant reading and know if you have been provides honest information. Keep in mind that many vehicle manufactures are putting brake fluid on routine maintenance every two years of so.

Most cars use DOT 3 brake fluid, which is OK for around-town driving -- but if you enjoy mountain driving or other forms of more aggressive motoring -- or you live in a very damp climate, you'll need to get the DOT 4 brake juice. The difference is in the WET BOILING TEMPERATURE -- the DOT 4 juice doesn't absorb moisture as quickly as the DOT 3 stuff, so it boils at a much higher temperature than the DOT 3 stuff -- which means less brake fade and more reliable stopping power. The DOT 4 Brake Fluid Tester was checked against a new (unopened) can of DOT 4 fluid. Tester is easy-to-read and is very accurate. Test showed that my old DOT 4 fluid had picked up some moisture in the last couple of years -- I installed a 4-wheel set of RUSSELL Speed Bleeders (purchased @Amazon) , and pumped out the bad stuff. With new DOT 4 brake fluid installed, braking is more positive. Better pedal feel, quicker stops, no fade with the clean DOT 4 fluid. The tester helped find the trouble and showed the extent of the moisture absorbed in the old fluid. UPDATE: 2/19/I7 -- I saved the old brake fluid in a clean, sealed jar and waited for it to separate. There was A LOT of nasty stuff in the old DOT 4 fluid, just as the Tester had indicated. Excellent product !!

This brake fluid tester gets the job done and is a bargain compared to the more sophisticated meters. I was hesitant to buy this due to the reviews about the sensitivity (or lack of) of this meter but my experience extinguished these fears. The meter has led dots on it that range from 0% to >4%. You dip the prongs into your brake fluid reservoir to check its condition. I'm not an engineer so I don't have all the terminology to explain how this meter works but I do know from using it that the meter measures the electric conductivity of the fluid because of the presence of water/moisture. Brake fluid itself is non-conducting. Now, the LED's and probably the circuit board on this meter are "built" such that if the amount of water is in between the values (borderline) of the LED readout values then you can see the next LED faintly light up. This tells me that the meter's LED's are able to show me the moisture level in a finer "gradient" fashion than what is spelled out by the LED's. In short, this tester is worth the $7 bucks that I paid for it.

Well built, great price. My car's ~2yr old Motul RB660 fluid showed 1% moisture. Though have not calibrated this tester using new, unopened brake fluid to confirm accuracy. Takes just a second to measure the brake fluid moisture content by dipping the probes into the brake fluid reservoir in engine bay. With such an easy way to get this information, every vehicle owner should use this or other similar tools to make informed decisions about when a brake fluid flush is actually necessary, rather than blindly rely on the mfg's rule of thumb or recommendations of many shops/dealers who are all to happy to push this high-profit service. Even for DIYers, this saves time, mess, cleanup and cost of unnecessary flushes.

The ultimate test would really be to start off in some new, clean brake fluid, but I don't have any. However, the brake fluid in my mom's car was tested at a local quick lube place recently and they said the moisture content was at 4%. It's actually the reason I bought this tester, because I don't trust those places, and sure enough I got a reading of 4%. Tested the fluid in my truck and it was bouncing between 1%-2%, which sounds about right since I had the fluid changed less than a year ago. So really, I'd say this device is something that everyone should have. Whether you're a DIY'er who changes their own fluids or you take your vehicle(s) to a shop for someone else to change them and you want to make sure that they're being honest with you, the $20-ish you spend on this tester is a small and necessary investment. Quick tip: When testing, make sure the probes are fully submerged to the point where the brake fluid touches the plastic to get the most accurate reading. When I only submerged the probes halfway in either vehicle, it was reading 1%-2% less.

Update: I tried using the tester out again, but this time I pushed the button before i dunked the electrodes into the brake fluid (the instructions are clearly a translation from a different language and actually instruct the user to do it both ways: button then dunk and dunk then button) - it seems as though button then dunk is correct. However, I ran into the same issue a previous reviewer ran into: if the electrodes are fully submerged the meter indicated >4% water and partially submerged it showed everything in between 2 and 4%. I followed the instructions he provided and used shrink wrap to expose only 3/8 of the electrodes (cover 1/8 with shrink wrap). This resulted in a consistent 2% water reading which goes in line with what I would expect from 2 year old Motul RBF600. As such I'm raising my review to 3 stars. I tried the product out on my brothers car which hasn't had its fluid changed in 8 years and the product showed 4% water which seems to be correct. Once I try the product out on new brake fluid in the next couple weeks I may revise again. Due to the required fix I won't give the unit 5 stars, however. I'm giving this a 2 star review as it seems to be able to tell when there is water in brake fluid (although I have yet to use it on fresh brake fluid - I will do so in a few weeks). However, I don't think the rating is believable. Here's why: The first test I conducted was on my every day car which had the brake fluid changed 2 years ago on the dot with Motul RBF600. A word about rbf600 first: it's a racing brake fluid that is supposed to have a higher than 'normal' boiling point both dry and 'wet'. That being said, the fluid is considered very hydrophilic - water loving - more so than your standard brake fluid. The test on the 2 year old rbf600 showed that it had less than 1% water. I was delighted to see this, but thought it was a bit suspect to see that 2 year old racing fluid to have so little water. The second test, what really clinched it for me, was on my mothers car. A far as I know the fluid hasn't been changed since 2006 (she's had the car since 2008, but even then the fluid should be fairly wet). The tester showed that the fluid also had <1% water. I honesty can't believe that brake fluid that is 8-10 years old only has 1% or less water in it. 2 stars because it seems to be able to tell when water is present (to be updated once I try it on fresh dot 4 rbf600 soon)

This is an affordable accurate measurement for DOT 3 & 4 brake fluid. My family has four cars and three motorcycles using DOT4. I knew most had not been flushed in a long time. Sure enough the three older vehicles measured >4% meaning they need flushing soon. The two year old motorcycle measured 2%. Out of curiosity, I measured a just opened bottle of Prestone DOT4 and it accurately read <1%. So easy to test I will be checking all of our vehicles yearly. Packaged well with battery and protective cap. My only complaint is the labeling on the device is some sort of white paint that is superficial. DOT 4 is very caustic and will erase the labels if not careful. For the price it is a good value for what it does.

Depends on how you interpret the item description, your opinion might vary. This is what it says today (8/18/2014) " Easy and quick way to test for moisture content in the brake fluid LED light indicators show percentage of water in the brake fluid Only takes seconds to know the results Suitable for cars using DOT 4 brake fluid (found in most cars produced since 2006) Takes 1 x AAA/1.5V battery (included) " To me it means it works on DOT3 (which is on all the vehicle I have, including ones newer than 2006), and ALSO works (suitable) with DOT4. If you look at this other vendor for OTC testing, which states clearly that it's product ONLY works with DOT4 (http://www.amazon.com/OTC-4598-Brake-Fluid-Tester/dp/B005R3SSCM/ref=pd_sbs_auto_1?ie=UTF8&refRID=05D1V6KDY1B9ZE91PZ6F, honest vendor description), you will understand how this vendor's description leads you to think otherwise. I bought the product, it arrived quickly. It failed the new DOT3 fluid that was just brought from Autozone. Wait a few days till I have time, spend hour+ going to Autozone to get another fresh bottle. Still no good, test failed at 3%-4%, and it test good for my old fluid which is semi orange at 1%-2%. Emailed vendor to see if I was doing any procedure wrong or just got a bad unit. Vendor was quick to response and we quickly conclude it was because I use it on DOT3 fluid. Vendor offer to 1. update the ad "try to make it clearer for our future customers" that the product is for DOT4 ONLY. 2. allow me to return the product. That was 6/19/2014, and the ad is still misleading to me. If the ad sounds clear to you that only works on DOT4, then please ignore this review. If it hints that it works with DOT3 for you, please be aware of this misleading vendor ad.