Does this brake fluid really need to be changed? (see photo)

My 2012 Camry XLE Hybrid has 71,505 miles on it. During my latest inspection, the mechanic recommended a number of fluid changes including a brake fluid flush based on the condition of my brake fluid. Attached is the picture of the fluid he gave me. Does it really need to be changed? It doesn’t seem that dirty to me. Thanks!


The problem is that brake fluid can absorb water, increasing corrosion and risking boiling. So yes, get it changed if it’s been 3 years or more.


I Agree change it.


Take a multimeter and set the scale to read 2 VDC.

Touch the negative lead to the negative post on the battery and the positive lead in the brake fluid in the reservoir.

If the reading is 0.30 VDC or more the brake fluid needs to be replaced,



Doesn’t much matter how it looks. Water contamination is clear.
However in my experience what’s bled out of the caliper always looks worse than what’s in the reservoir.
I change every 3 years.


You can buy a brake fluid tester that will test the water content.

9 Best Brake Fluid Testers Reviews and Complete Guide 2021 – Rx Mechanic


I presume it’s never been changed. So it is now 9 yearsand 71K miles old. hmmm … well, you could probably get by for a while w/o changing it. But there’s a risk involved b/c as noted above the brake fluid tends to get some water in it and that will eventually rust your brake system’s innards and cause all sorts of grief. So you are probably better off to go ahead and change it.

One other thing to consider: There’s different types of brake fluid. Dot 3, Dot 4, Dot 5 are the most common. The Dot 3 is what I use and it will definitely get water in it. I think the Dot 4 also accumulate water. But the Dot 5 doesn’t get water in it, at least not much. So if the car came equipped w/Dot 5 you may be good to go. Double check w/you mechanic about the Dot 4 and Dot 5 thing b/c I may have the mixed up. I don’t think you are supposed to interchange Dot3/4 and Dot 5 btw. Stick w/the type your car came with.

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Thanks for all the great advice everyone!

Correct George, DOT 3 and 4 are hydrophilic so they attract water whereas DOT 5 is Hydrophobic. DOT 3 & 4 are interchangeable, though DOT 3 has a lower boiling temperature. DOT 5 is Silicon based and can’t be mixed with DOT 3 & 4.


What is the theory behind the volt meter test?

Water conducts electricity. Pure brake fluid doesn’t conduct easily.

My 23-year-old brake fluid looks great and works fine.

But why is a voltage generated?

That is the automotive equivalent of the guy who says “I’ve been smoking for X years and I don’t have lung cancer, or emphysema, or heart disease”. The word that is missing in both cases is… “yet”.

Everything tends to work well… until it doesn’t. Preventive maintenance is the way to keep problems from taking place, or at least to forestall them.

I bought a “grandma” car in 1977. It was a 1960 Ford Falcon, and it had been driven less than 20k miles in 17 years. When I had my mechanic go over it to see what was needed, he said that the brake fluid contained an incredible amount of water. Luckily, the wheel cylinders weren’t damaged, and I was able to drive it for several years without incident, but if I had needed to brake on a long downgrade before he flushed the brake system, I almost surely would have lost braking ability when that mixture of brake fluid and water boiled.

Thank you for asking this. I too have been trying to figure that out as well.

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Seriously ? Lets hope no one decides to do the same .


From my understanding the moisture causes a conductive path between the dissimilar metals in the brake system and this causes a galvanic reaction.


That makes sense!

Here’s another question - why do brake systems typically use type 3 or 4, and not an oil or silicone-based fluid, to eliminate water absorbing issues? The seals would need to be different, but plenty of hydraulic systems handle it fine.

A guess: DOT 5 costs a lot more than DOT 3. Combine that with the need to change out some brake components, the benefits to the average owner of the average vehicle doesn’t outweigh the costs involved. Remember, the manufacturers have set brake fluid change requirements that prevent the vast majority of water contamination problems anyway.