Brake Fluid Flushing or Did I Get Flushed?

Francizek May 3
Correct me if I’m wrong, but aren’t today’s brake systems pretty much sealed against air-laden moisture getting in?

You are correct. In this case Pretty Much means about a three year interval.

Why the heck are you people talking politics in a thread about brake system flushing?
Can’t you keep your political stupidity in check in some other location?

BC.

I have owned three Honda Accord LXs (1990, 1995, and 2004). The 1990 and 1995 had over 250,000 miles. The 2004 currently has 246,000. NOT ONCE have I ever added for flushed the brake fluid and NOT ONCE have I had any brake issues. So, I’m not convinced a brake fluid flush is necessary. All I’ve ever done is checked the fluid level, and it’s ALWAYS been between the MIN and MAX marks.

I think a lot of it has to do with how well sealed the brake system is from exposure to outside moisture, and the quality of the rubber parts in the system. Changing it out every 3 years could be based on a worst case scenario situation of constant use in a high moisture environment with hydraulic parts that are poorly sealed. If brake fluid absorbs too much moisture, it won’t just corrode parts, but it can lower the boiling point of the fluid and the fluid can boil out of the wheel cylinder during times of heavy brake use and high heat. Then surprise surprise the brakes won’t apply again and the pedal sinks to the floor after letting off at the bottom of that steep hill!

Brake fluid should be like gasoline. If it’s in a completely sealed container, it shouldn’t ever go bad.

Neither car has brake fluid flush listed as a maintenance item, though I do request it be done when it is time for pads and rotors.

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Brake fluid is NOT fully sealed.

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And it would not matter if it was sealed… water will migrate through the rubber hoses and the master’s cap diaphram over time anyway. The brake system will also generate debris that can foul proportioning valves or ABS valves.

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The advice about periodic replacement is spot on when it comes to brake fluid, based on the overall odds of something going wrong. That is to say, statistically it is a good move. Our own individual experiences may tell us that we’ve had good luck even though we haven’t followed the usual recommendations, but that is a single anecdotal example and is not a good reason to reject the general guideline. It is a very human tendency to think that our own personal experiences are typical of the larger picture, but that is just one case out of thousands and may or may not reflect the general trend. You can’t reliably make a generalization based on only one case.

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Then you’ve gotten lucky, congratulations. Doesn’t mean you’re right though, it means you’ve gotten lucky.

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Some vehicles seem to be more robust about brake fluid issues than others. I have to replace the brake fluid on my truck periodically even though it is still clear-looking, every 3-5 years, or the wheel cylinders and master will start leaking. On my Corolla, one interval where I was very busy I didn’t replace the brake fluid in 8 years, fluid got pretty black, but still no wheel cylinder or MC leaks. The truck is a lot heavier and has drum brakes all around, vs the Corolla’s front discs, may have something to do w/it.

That’s sort of surprising. The brake fluid level goes down as the brake pads wear, so unless you’ve never wore the brake pads enough to have to replace them, usually at some point the brake fluid level would go below the “min” and you’d get a warning light on the dashboard.

Back to the OP if your brake fluid is black you have more to worry about than a flush imhop

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The OP made one post in April of 2011 and has not been back since .

Thank you hikerguy for reviving a 11 year old thread with advice that might only work on very few occasions.

I hate when that happens, sometimes it is fine, other times wasted time. @VOLVO-V70 you have a mind like a steel trap, the things you remember or relating to previous posts. Do you keep a spreadsheet? I try to note pertinent info, but have forgotten most of it.