Why: The fluid in your car’s brake hydraulic system transfers your foot pressure at the brake pedal into stopping power at the wheels. An adequate supply of clean brake fluid is absolutely essential for safe vehicle operation. Old, moisture-contaminated brake fluid, or a low fluid level that allows air to enter the system, can lead to brake fade or a complete loss of braking power.
When: Inspect the brake fluid level at every oil change. If the level has fallen below the “low” mark on the fluid reservoir, it usually indicates major brake wear or a leak somewhere in the system; have the brakes inspected as soon as possible. Most vehicle manufacturers recommend that the brake fluid be replaced periodically to flush moisture and contaminants from the system. Every two years is a common interval; check your vehicle owner’s manual for specific recommendations.
Bottom line: Old brake fluid or fluid at low levels can result in your brakes fading or completely failing. Plus, a leak in the brake line can cause a vehicle fire if the fluid drips onto a heated surface such as a catalytic converter.