Recent Topics
2007 Ford Fusion Cam Pics
by tig1 - 08/23/19 05:31 PM
Cloning a Lexus key
by Nayov - 08/23/19 04:23 PM
2011 GMC Acadia Shock/Strut Replacement
by panthermike - 08/23/19 03:49 PM
Confusion on oil to use on BMW 328i 2010
by goldenjava - 08/23/19 03:21 PM
Oil Confusion for 2010 BMW 328i
by goldenjava - 08/23/19 03:16 PM
ProSelect 27356 cut open
by Sayjac - 08/23/19 03:04 PM
Electrolux - Dryer reliability warning.
by pezzy669 - 08/23/19 02:37 PM
Microfiber Towels for different applications?
by Quattro Pete - 08/23/19 01:53 PM
Coated vs. painted rotors
by atikovi - 08/23/19 01:13 PM
New spark plugs, occasional misfire
by avacado11 - 08/23/19 12:34 PM
clean or replace o2 sensor?
by bionictony - 08/23/19 12:15 PM
Supertech equivalent
by Bettez88 - 08/23/19 12:06 PM
Federated OF Now Made in China
by Mr_Luke - 08/23/19 11:47 AM
Sourcing Particular Brembo Rotors
by RamFan - 08/23/19 11:22 AM
Intermittent Braking Vibration?
by Gebo - 08/23/19 10:59 AM
Northrop B-2 Spirit - First Cockpit Video
by john_pifer - 08/23/19 10:36 AM
ADBV Design - MANN Filter
by LeoStrop - 08/23/19 10:25 AM
"MYSTERY Oil" - 320 ppm Zinc
by Linctex - 08/23/19 10:20 AM
Thoughts on Time v Mileage
by BISCUT - 08/23/19 10:04 AM
Newest Members
goldenjava, Spuzzum, ta249, bobsauto62, Ramz
69044 Registered Users
Who's Online Now
82 registered members (akela, 53' Stude, ArrestMeRedZ, 92saturnsl2, Astro14, Alfred_B, 9 invisible), 2,088 guests, and 30 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Most Online3,532
Jul 30th, 2019
Donate to BITOG
Print Thread
Hop To
Cheap brake fluid tester working properly? #4108630 05/28/16 04:00 AM
Joined: Jun 2011
Posts: 77
LucasDK Offline OP
OP Offline
Joined: Jun 2011
Posts: 77

I bought this tester on Ebay from China:

As you can see from the reviews, people are extremely satisfied with the tester.

I made a test in a bucket of water and it rapidly showed +4% water as it should. But then I tested some old brake fluid which has been on the shelf for 4 years. 4 years ago the container was opened and the plastic screw lid (with no seal) was put on again. It has been resting like this in a shed experiencing summers and cold winters and relative moistures going above 95%.

But my tester shows less than 1% water in the fluid. Which means the fluid should be OK. But can I trust the tester?

PS: I also tried the tester with the brake fluid in my cars brake fluid reservoir and again it showed less than 1%. But I do not know when it was changed the last time because I bought the car 6 months ago (used car).


Toyota Hiace 2,4D (2L engine)
Toyota Corolla AE92, (4A-FE engine)
Ford Model A (3,4 liter engine)
Re: Cheap brake fluid tester working properly? [Re: LucasDK] #4108656 05/28/16 05:31 AM
Joined: Oct 2012
Posts: 4,825
Ducked Offline
Joined: Oct 2012
Posts: 4,825
In principle, should be easy enough to test.

Buy some fresh brake fluid (which might be date-coded?).

Test a sample, then spike it with steadily increasing known percentages of water to produce a calibration curve.

That's likely to be more specifically informative than anything anyone on here can tell you about your brake fluid tester.

Re: Cheap brake fluid tester working properly? [Re: LucasDK] #4108657 05/28/16 05:31 AM
Joined: Feb 2009
Posts: 3,653
Jetronic Offline
Joined: Feb 2009
Posts: 3,653
why not add 1% water to a sample of the brake fluid, and test again?

AR Giulietta 2.0 JTDM-2 -- Total Quartz 9000 Energy 0w30
Hankook Ventus Prime 2 215/50R17 (front)
Pirelli P7 Cinturato 225/45R17 (rear)
Re: Cheap brake fluid tester working properly? [Re: LucasDK] #4108669 05/28/16 05:47 AM
Joined: Feb 2012
Posts: 838
larryinnewyork Offline
Joined: Feb 2012
Posts: 838
I have one of those testers.
How reliable is the accuracy ? I don't know.
I tried it a couple times and now it sits in the basement.
I change my brake fluid every 2 years. So no matter what the Tester would show, I should be good.
I thought it was an interesting purchase and may just use mine for reference or to show a family member how bad their (neglected) fluid is.

Read the instructions. It says:
Dip the test probes into the brake fluid up to the plastic rim of the device.

Check for Repeatability by how far you insert the probe.
This is where I was getting inconsistent readings.

Re: Cheap brake fluid tester working properly? [Re: LucasDK] #4108799 05/28/16 09:58 AM
Joined: Jun 2009
Posts: 830
bowlofturtle Offline
Joined: Jun 2009
Posts: 830
ive only used strips. It was supplied to me by BG products, i think they were rigged a little since it can help BG sell their brake flush. But what do i know.

Honestly now... i dont care too much. I've seen fluid look like used oil in cars from early 90s, the brakes all work and i wouldn't suggest them do a brake flush. My personal cars, i bleed a little every brake job and i'm not thinking twice.

Maybe your test of 100% water was too much water for the tester, LOL

My toys
-05 Infiniti G35x 140k
-03 Suzuki SV650N 8.5k
-16 Jetta 1.4T 20k
-98 Nissan Maxima 160k
-09 Toyota Camry V6 96k

Re: Cheap brake fluid tester working properly? [Re: LucasDK] #4108964 05/28/16 02:04 PM
Joined: Apr 2013
Posts: 3,504
Nate1979 Offline
Joined: Apr 2013
Posts: 3,504
The dirtiest fluid is always at the calipers. How are these testers measuring anything useful?

2015 GMC Sierra 2500 6.0L
2010 Subaru Forester 2.5X
Previous Thread
Next Thread

BOB IS THE OIL GUY® Powered by UBB.threads™