Why is it necessary to replace brake fluid?

[StellaLynn]

There are two main reasons for replacing brake fluid: 1. Brake fluid directly affects braking performance. Due to weather and external factors, brake fluid absorbs moisture and impurities over time, leading to deterioration. This results in insufficient braking force, creating safety hazards. 2. Contaminated brake fluid causes wear to sealing components in the braking system, shortening the lifespan of brake parts, making regular replacement essential. Additional information: How brake fluid works 1. When the brake pedal is depressed, the hydraulic system pressurizes the brake fluid. 2. The pressurized fluid from the master cylinder is distributed to all four wheel cylinders. 3. The pistons in wheel cylinders are actuated by the pressurized fluid, forcing brake pads to clamp the rotors.

[DeMadeline]

I used to drive an old car. Once during a long trip, the brakes suddenly became extremely spongy, nearly causing an accident. Later I learned the brake fluid hadn't been changed for two years and had absorbed too much moisture, lowering its boiling point. During continuous braking, the fluid vaporized directly, causing brake failure. What's even scarier is that old brake fluid can corrode brake calipers and lines, leading to expensive repairs. Moreover, aged brake fluid becomes viscous, with reduced flow at high temperatures - the pedal feels heavy and emergency braking response lags. I've since wised up and now change it every 40,000 km or two years. Brake fluid is cheap, but it can be life-saving in critical moments.

[Aaron]

Last time during maintenance, the technician taught me to check the brake fluid, saying it's like a sponge constantly absorbing water. Used brake fluid with over 3% water content can boil and vaporize after just a dozen or so brake applications on continuous downhill slopes. At that point, the brake pedal would feel empty when pressed, like stepping on cotton—how dangerous! Plus, the impurities mixed in can wear out the ABS pump, and replacing one could cost as much as dozens of bottles of brake fluid. That's why I insist on regular changes, especially in humid southern regions where it's even more crucial, to ensure the braking system remains reliable at all times.

[VonArianna]

I've noticed many car owners only remember to change the engine oil, when in fact brake fluid is far more critical. Degraded brake fluid under high temperatures has poor flow characteristics, causing slower retraction of caliper pistons - the dragging brake pads significantly increase fuel consumption. After absorbing moisture, brake fluid's boiling point drops by at least 30%. Through testing, I found used fluid starts bubbling at 160°C while fresh fluid withstands over 260°C. Regular replacement also prevents corrosion - those rust crystals forming in the lines can cause sudden lock-ups or leaks. Whenever I see the maintenance manual's specified brake fluid interval, I make sure to change it on schedule.