How often do you change brake fluid in your car?

[ken masoumi]

I just took my Civic(70.000 mile on the odometer) to the local mechanic to change the front pads and possibly the rotors, the car has never had a brake service done since I bought it new in 2007,I asked the mechanic if he's going to change the brake fluid he said they usually don't "if it's not needed" ,Honda recommends every 3 years or 30.000 miles, some believe the brake fluid does not need to be changed since it is a "sealed system" ,I can't be sure it is as sealed as they claim it to be.
How often do you change your brake fluid?

[Chris Padilla]

The intervals I hear the most often is every 2 years so that is what I do when I change mine.

[Robert Engel]

I've never done it. My mechanic (who's never steered me wrong so far) says its optional.
Maybe that's wrong, but I've owned alot of vehicles in the last 40+ years.
I;ve had trucks with up over 300,000 mi. on them and never had an issue.

BTW, same thing with transmission fluid. The only time I changed it I within a day or two I had trouble with it.
Now, I never change it either.

[Ken Fitzgerald]

I change mine every 3 years. I live in a mountainous area where brakes are important.

[Howard Garner]

My manual says every 2 years, I have averaged every 3 years or so.

Howard Garner

[Greg R Bradley]

I'd be skeptical of it being a "sealed system". There are some reservoirs that have a rubber diaphragm between the vented top portion and the fluid. Possible, but not likely on your Honda. IF he is wrong about that then ?????

Conventional brake fluid is hydroscopic and pulls moisture from the air. If you are in a warm/moist climate I would change every two years as the moisture gets IN everywhere and the hydroscopic fluid is absorbing the moisture that gets in through the vent hole in the cap. I'm in dry SoCal and always did that every 3-4 and checked the system for moisture as I was doing it. Any COMPETENT mechanic should have a supply of moisture test strips.

Later systems are more likely to use fluids that are not hydroscopic. The fluid in my 1991 Jaguar was still passing moisture test after 20 years but that fluid is not cheap.

Sometimes you want to change it just to flush fresh fluid through the system so that you can see any discoloration in the fluid coming out, which could tell you the condition of the flexible brake lines and seals.

Bottom line is there is no standard answer.

[Ken Fitzgerald]

It depends on the type of fluid used in your system but non-silicon brake fluids are hygroscopic. They absorb moisture from the air. The water vapor absorbed reduces the temperature at which the brake fluid will boil and turn to a vapor. Vapor in your brake lines/system can lead to brake failure.

The area where I live is relatively arid so though it's recommended to change it every 2 years, I go 3 years but I do change it.

[Malcolm Schweizer]

I would say two years, but it also depends on the car, the climate, and the driving conditions. On my 1972 VW I would change it very frequently. Okay, actually it would sometimes change itself, but that's another story. On my Jeep Liberty I shoot for 2 years, but sooner if it is brown looking. We have very steep roads, so the brakes get a lot of wear and tear. Also we are in a humid environment, and condensation can build up in the lines.

Even though it's a "sealed system," condensation still gets in, and also the fluid breaks down in the high heat generated during braking. As it breaks down or as water builds up in the system, the fluid becomes more compressable, and therefore the brakes get mushy.

If you have ABS, then you need to have a mechanic bleed it unless you have a pressure bleeder. You can really mess things up otherwise. There is a diaphragm in ABS systems that has to be pressure bled or else it deforms. Also the OBDII fault codes may need to be reset if you don't have a code reader.

[Pat Barry]

I have never changed the brake fluid, only topped it off after bleeding as part of a caliper rebuild

[ken masoumi]

I just got my car back, the mechanic said the fluid was "fine" so he did not change it, just topped it up after replacing the front brake pads,I must add he is recommended by a few neighbours who described him as a trustworthy no nonsense mechanic.

[Chris Parks]

And I would ask him how he knew it was fine. He may be correct and the car might have silicone fluid but all the same I would want to know how he concluded it was fine.

[Myk Rian]

I've never done it. My mechanic (who's never steered me wrong so far) says its optional.
Maybe that's wrong, but I've owned alot of vehicles in the last 40+ years.
I;ve had trucks with up over 300,000 mi. on them and never had an issue.

BTW, same thing with transmission fluid. The only time I changed it I within a day or two I had trouble with it.
Now, I never change it either.

+1 and +1
Have never changed either.

[Mel Fulks]

Agree with Chris. It could look "fine",can he see if it has taken on moisture? There are warnings on brake fluid cans to put
the top back on immediately. I've seen guys checking fluid leave top off resovoir while they go find more fluid to top off.

[daryl moses]

I usually just trade.......

[Rick Potter]

I had a Ford pickup, back when anti lock brakes were just becoming common. As has been said, brake fluid is hydroscopic, absorbing moisture. The brakes worked fine after it had some mileage on it, but the anti lock light stayed on.

The anti lock valve that operated the system had gotten rust inside and quit working, which made the truck revert to a default system of normal, non anti lock braking. It cost $1,000 to fix.

I have no idea if the newer systems are better guarded or not.