“Tiny bit of water added”? More like volumetrically about half water and half new brake fluid now. Try just adding a drop. Remember your tester looks for between 1 and >4% water. Your test represented adding 50% water to your system. Also metal pans skew results. Use glass or plastic.
been a mechanic 30 years plus we do use these but they can go off scale best rule of thumb is whats in your reservoir isn't what's in you caliper pistons or more so in the brake drum cylinders as most of the moisture is drawn by the seals does that pen have a means of calibrating? anyway great vid as usual fred.
Thanks for the info John, esp the part about the cylinders. Once your past 2 years with DOT4 is best to change the fluid as part of a service regardless of what the tester says. No on these cheap test pens they are pre set for DOT4 only.
every two years minimum is recommended for brake fluid best practice is to replace reservoir fluid as you have shown using syringe or vacuum,fill with new and start extraction from furthest point though further actions depending on abs or dsc system may be required. like tyres brake fluid is very overlooked and glad you have brought this to attention fred good man.
Have you tested that hypothesis? What is stopping the water from being evenly distributed throughout the brake fluid? It seems much more likely that the water would quickly move throughout the system until it was evenly distributed, just like smoke in a room. If you put a drop of water in a jar of fluid, does it sit on top the fluid, settle at the bottom or quickly mix on its own almost instantly?
What would happen if you use distilled water instead of tap water? Just wondering whether the electrolites in the normal tap water could throw off the readings
Hi Fred, I have one of these pens and I get varying results depending on the depth of the probe into the brake fluid. As others have said the metal will affect the conductivity too. I don't expect too much from this tool but if your viewing a second hand vehicle or want to check that you garage has done what is has put on the invoice then it certainly has its place. When I brought a motorbike second hand you could not only feel the lever was spongy the tool lit up like a Christmas tree so it has its uses. I wonder if it could be used to measure SWR? :-) Say hi to Jez and the lads on the 305 net, 73 Rob/19CT019
Same with me...I tested a car I just did a few months ago and it failed. If I barely put probe in brake fluid it's ok. So I think it's only accurate barely in brake fluid. I tried on old fluid and barely in fluid and it still failed.
I'm sorry, but this is test method is so flawed, the results are of no use. Metal cups are conductive and it looks like both probes touched the metal in the last test. Why not measure and add precisely 1% water, then 2% water and place the fluid in glass or non-conductive cups. Certainly the depth the probes go into the fluid matters, as this probe is measuring impedance, so the more coverage area of the probe tips, the higher the reading. So fully submerging the probe tips for each measurement would be required for repeatability. If you didn't have training in how to conduct a lab experiment in school, these details are not obvious. It would also be vital to test with distilled water and tap water. I doubt that tap water is seeping into anyone's car brake systems. Water on it's own isn't conductive, so unless adding water to brake fluid produces some ions in the solution, this device is really measuring the amount of contamination other than water in the fluid being tested. So it seems doubtful that this thing can actually measure moisture content of brake fluid at all. It is measuring the level of ionic contamination, which is useful for avoiding corrosion.
I'm trying to understand why you went through the trouble of testing this but were so incredibly unscientific about it: 1) Why use tap water when you can use distilled water? The water its going to be contaminated with is atmospheric water which should be pretty pure. 2) Why use metal pans when you can use plastic? 3) Why use random amounts of fluid when you can use controlled amounts. You've got a syringe, use it properly. Take 100ml of new fluid... Measure it. Add 1ml of distilled water, measure it. Add 1 more ml of distilled water, measure it. Add 1 more ml of water, measure it. Add 1 more ml of fluid and measure it. You can then do the same thing with the used fluid.
And so how many ohms resistance should good brake fluid be, and how many ohms resistance would qualify as bad brake fluid? Or do you even know what I'm asking??? Do you know what ohms are???
@@alan4sure put some piece of tape arround the terminals, first mesure clean DOT4 brake fluid. There should be no flow as far as i know because oils dont conduct electricity, then mesure the one in your car.
@@igor6388 And if you try an ohm meter in water as I just did, you get no reading either. It is infinitely high resistance. So even if your Dot 4 brake fluid had become 100% water, a simple ohm meter wouldn't tell you anything. It would read the same because neither water nor brake fluid conducts.
@@igor6388 Neither one conducts. That's my point. Unless using very high voltage, then water will conduct, but a meter is not high voltage. It's very low, less than 12v. So your test simply won't work. Go try it.
The info is just false , dot 5.1 has the same base , its just a little bit better than dot 4 . Bosch now uses the ENV6 brake fluid for dot 3\4\5.1 brake fluid systems . dot 5 is silicon based , used for racing cars . I use dot 5.1 for more than 10 years on my cars and the recommended change interval is 3 years (same for the new ENV6)
That's complete BS - brake fluid is NOT supposed to be full of moisture after 2.5 years not to mention that testing in metal/foil dishes is a bad idea - the tester - AT LEAST PARTIALLY - bases its analysis on resistance.
“Tiny bit of water added”? More like volumetrically about half water and half new brake fluid now. Try just adding a drop. Remember your tester looks for between 1 and >4% water. Your test represented adding 50% water to your system.
Also metal pans skew results. Use glass or plastic.
I got one the same and it works spot on to me ...hope this helps
been a mechanic 30 years plus we do use these but they can go off scale best rule of thumb is whats in your reservoir isn't what's in you caliper pistons or more so in the brake drum cylinders as most of the moisture is drawn by the seals does that pen have a means of calibrating? anyway great vid as usual fred.
Thanks for the info John, esp the part about the cylinders. Once your past 2 years with DOT4 is best to change the fluid as part of a service regardless of what the tester says. No on these cheap test pens they are pre set for DOT4 only.
every two years minimum is recommended for brake fluid best practice is to replace reservoir fluid as you have shown using syringe or vacuum,fill with new and start extraction from furthest point though further actions depending on abs or dsc system may be required. like tyres brake fluid is very overlooked and glad you have brought this to attention fred good man.
A silent killer John. Thanks for the info. Iam sure it will help folks in the future.
Have you tested that hypothesis? What is stopping the water from being evenly distributed throughout the brake fluid? It seems much more likely that the water would quickly move throughout the system until it was evenly distributed, just like smoke in a room. If you put a drop of water in a jar of fluid, does it sit on top the fluid, settle at the bottom or quickly mix on its own almost instantly?
£2.19 at eBay UK for what appears to be the same item "Car Brake Fluid Tester Pen For Water Moisture Compact Tool Indicator DOT 3 / 4"
What would happen if you use distilled water instead of tap water? Just wondering whether the electrolites in the normal tap water could throw off the readings
Good point. Yes it could.
Do you think the metal conductive containers used for the test may have altered the results Fred ?
No i dont think so. I tried the pen in milk and tea and it showed different results.
Yes, small glass bottles could have been used.
Hi Fred, I have one of these pens and I get varying results depending on the depth of the probe into the brake fluid. As others have said the metal will affect the conductivity too. I don't expect too much from this tool but if your viewing a second hand vehicle or want to check that you garage has done what is has put on the invoice then it certainly has its place. When I brought a motorbike second hand you could not only feel the lever was spongy the tool lit up like a Christmas tree so it has its uses. I wonder if it could be used to measure SWR? :-) Say hi to Jez and the lads on the 305 net, 73 Rob/19CT019
Same with me...I tested a car I just did a few months ago and it failed. If I barely put probe in brake fluid it's ok. So I think it's only accurate barely in brake fluid. I tried on old fluid and barely in fluid and it still failed.
Awesome information! Thanks for explaining
I'm sorry, but this is test method is so flawed, the results are of no use. Metal cups are conductive and it looks like both probes touched the metal in the last test. Why not measure and add precisely 1% water, then 2% water and place the fluid in glass or non-conductive cups. Certainly the depth the probes go into the fluid matters, as this probe is measuring impedance, so the more coverage area of the probe tips, the higher the reading. So fully submerging the probe tips for each measurement would be required for repeatability. If you didn't have training in how to conduct a lab experiment in school, these details are not obvious. It would also be vital to test with distilled water and tap water. I doubt that tap water is seeping into anyone's car brake systems. Water on it's own isn't conductive, so unless adding water to brake fluid produces some ions in the solution, this device is really measuring the amount of contamination other than water in the fluid being tested. So it seems doubtful that this thing can actually measure moisture content of brake fluid at all. It is measuring the level of ionic contamination, which is useful for avoiding corrosion.
Yep fair comment.
I got mine off eBay for $ 2.50 - useful tool indeed
Seems to work. Not sure how accurate ?
Thank you. This is a useful video.
Glad it was helpful!
I think you are wrong with Dot 5.1. It still absorbs water.
I'm trying to understand why you went through the trouble of testing this but were so incredibly unscientific about it:
1) Why use tap water when you can use distilled water? The water its going to be contaminated with is atmospheric water which should be pretty pure.
2) Why use metal pans when you can use plastic?
3) Why use random amounts of fluid when you can use controlled amounts. You've got a syringe, use it properly. Take 100ml of new fluid... Measure it. Add 1ml of distilled water, measure it. Add 1 more ml of distilled water, measure it. Add 1 more ml of water, measure it. Add 1 more ml of fluid and measure it. You can then do the same thing with the used fluid.
All fair comments.
I learnt more from the comments than I did from the video
love it thank you your work
You could also just use a multi meter to messure resistance of any liquid
And so how many ohms resistance should good brake fluid be, and how many ohms resistance would qualify as bad brake fluid? Or do you even know what I'm asking??? Do you know what ohms are???
@@alan4sure put some piece of tape arround the terminals, first mesure clean DOT4 brake fluid. There should be no flow as far as i know because oils dont conduct electricity, then mesure the one in your car.
@@igor6388 And if you try an ohm meter in water as I just did, you get no reading either. It is infinitely high resistance. So even if your Dot 4 brake fluid had become 100% water, a simple ohm meter wouldn't tell you anything. It would read the same because neither water nor brake fluid conducts.
@@alan4sure Water doesn't conduct xDDD. Try putting 12volts into water and then use a multi meter to mesure the + or -
@@igor6388 Neither one conducts. That's my point. Unless using very high voltage, then water will conduct, but a meter is not high voltage. It's very low, less than 12v. So your test simply won't work. Go try it.
The info is just false , dot 5.1 has the same base , its just a little bit better than dot 4 . Bosch now uses the ENV6 brake fluid for dot 3\4\5.1 brake fluid systems . dot 5 is silicon based , used for racing cars . I use dot 5.1 for more than 10 years on my cars and the recommended change interval is 3 years (same for the new ENV6)
Thank you
Nice one Fred!!!
WOULD NEVER THINK OF BRAKE FLUID,,,THANKS FRED,,DES CREAN BELFAST IRELAND,, 68CT022
They call it the silent killer Des. Every 2 years.
US $0.01 on aliexpress...
That's complete BS - brake fluid is NOT supposed to be full of moisture after 2.5 years not to mention that testing in metal/foil dishes is a bad idea - the tester - AT LEAST PARTIALLY - bases its analysis on resistance.
added too much water..
All good intresting video as allway take care mark from loughbrough leicestershire ct 2674
Cheers Mark