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Discussion Starter #1
I'll be honest- I don't think I've ever replaced brake fluid in my life in any of my cars. I'm certain that my mechanics didn't replace/flush my brake fluids either. Never a problem. With my Porsche I'll be sure to follow their maintenance schedule though.

Do you Doityourselfers replace the brake/clutch/coolant as required? If you track your car I get it... the brake fluid needs replacement. Do you think the required replacement schedule is over aggressive? Maybe I've just been lucky!
 

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Brake fluid is hygroscopic. That means it absorbs moisture out of the air/atmosphere (regardless of miles). When you apply the brakes, it compresses the brake fluid to engage the pistons in the caliper, which then makes the brakes work.

If there's excess water in the brake fluid, as it heats up, it'll boil the the water turning it to steam. Steam compresses, which means there is no longer enough pressure to operate the pistons. Therefore, pedal goes to the floor, and there's no brakes!

A lot of people get away with it, but especially given the criticality of the braking system, I would strongly recommend having the fluid flushed every two years on every car. For a car that's tracked, I'd say a minimum of once a year, if not twice a year.
 

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Discussion Starter #3
Brake fluid is hygroscopic. That means it absorbs moisture out of the air/atmosphere (regardless of miles). When you apply the brakes, it compresses the brake fluid to engage the pistons in the caliper, which then makes the brakes work.

If there's excess water in the brake fluid, as it heats up, it'll boil the the water turning it to steam. Steam compresses, which means there is no longer enough pressure to operate the pistons. Therefore, pedal goes to the floor, and there's no brakes!

A lot of people get away with it, but especially given the criticality of the braking system, I would strongly recommend having the fluid flushed every two years on every car. For a car that's tracked, I'd say a minimum of once a year, if not twice a year.
Not going to argue. I guess the manufacturers know better than me for sure. But hoe exactly does moisture get into the brake lines? It’s a sealed system except the reservoir.
 

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Not going to argue. I guess the manufacturers know better than me for sure. But hoe exactly does moisture get into the brake lines? It’s a sealed system except the reservoir.
Good question and I don't know, but I suspect because the pistons in the brake calipers have to move that this might be a source of contact. One brake source stated: "brake fluid is hygroscopic by nature which means it absorbs water from the environment via seams and microscopic pores in your hydraulic lines" as a reason.
 

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With the help of a friend, I replaced the fluid in mine after year one with Castrol SRF before a track weekend. I’ll change it again after a year as it is easy to do.
 
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