How to Check Brake Fluid?
2 Answers
After opening the engine compartment cover, you can directly see the upper and lower scale lines on the outside of the brake fluid reservoir. The brake fluid level must be between these upper and lower limit lines. Below is relevant information: 1. Brake fluid is generally replaced every 2 years or approximately 40,000 kilometers. This is not absolute and depends on the vehicle's usage. Brake fluid has certain corrosive properties and strong water absorption, so a dedicated brake fluid tester can be used to check the moisture content in the brake fluid. You can also observe the color of the brake fluid; if it appears black, it is likely time for replacement. 2. When the heat generated by the friction between the brake pads and brake discs raises the temperature of the brake system to the boiling point, the moisture in the brake fluid will boil and produce bubbles. Since gas is compressible, when there is a certain amount of bubbles in the brake lines, pressing the brake pedal will feel soft, and the braking force will be noticeably insufficient. In severe cases, braking force may even be lost.
I've been driving for many years, and checking brake fluid is a simple yet crucial safety step. After parking, wait for the engine to cool, open the hood, and locate the plastic reservoir with the brake symbol in the engine bay—usually semi-transparent for easy fluid level inspection. The fluid level must be between the MIN and MAX marks; if it's low, don't drive as there might be a leak. Brake fluid is highly hygroscopic, absorbing moisture over time, turning dark and cloudy, which reduces braking efficiency and increases the risk of brake fade. I check the fluid level and color every two weeks: new fluid is light yellow and clear, while old fluid darkens, signaling it's time for a change. When low, I top it up with professional-grade brake fluid, ensuring compatibility with my car model (e.g., DOT3 or DOT4). I recommend a full replacement at a repair shop every two years to confirm the system is leak-free. Remember, never mix other liquids—they can corrode parts and degrade overall performance.
