Brakes
Brake fluid: the maintenance item nobody talks about
It is hygroscopic, which is a fancy way of saying it drinks water out of the air — and water in a brake system is bad news.
· 6 min read
What brake fluid does and why it fails
Brake fluid is the incompressible link between your foot and the calipers. It also absorbs moisture through hoses and reservoir seals. At around three percent water content the boiling point drops far enough that hard braking on a long hill can create vapor, and vapor compresses — that is the soft pedal people describe after a mountain drive.
Water also corrodes caliper bores, master cylinder seals and expensive ABS modulator valves from the inside.
How we test it
Moisture test strips and a refractometer reading, plus a visual on color and debris. Clear amber is healthy. Dark brown with sediment means overdue. Most manufacturers call for a two to three year interval regardless of mileage.
Can it wait?
If the fluid tests clean, yes. If it is over three percent water, do it before the next winter — cold, wet, salty roads are the worst environment for a corroding brake system.
Bone says: here's why
Why flush fluid that looks fine? Because water is invisible in brake fluid, and it eats the parts you cannot see.
Let's keep your vehicle healthy.
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