What Causes Brake Fluid Deficiency?
2 Answers
The causes of brake fluid deficiency include leakage from the brake fluid reservoir, damage to the brake lines leading to brake fluid loss, leakage from the brake master cylinder, and leakage from the brake slave cylinder. A lack of brake fluid can introduce air into the braking system during operation, resulting in brake failure and compromising vehicle safety. Below are the steps for bleeding air from the car's brake system: 1. First, locate the bleeder screw on the brake slave cylinder, remove the dust cap from the bleeder valve, and then connect a rubber tube from the bleeder port to a drain bottle. 2. This step requires two people to cooperate. One person should press the brake pedal 4-5 times inside the car and then firmly hold the pedal down. Meanwhile, the other person loosens the bleeder screw on the brake slave cylinder, allowing air to escape along with the brake fluid. 3. Repeat the above steps until only brake fluid is discharged, indicating that all air has been purged from the brake lines. 4. Finally, tighten the bleeder screw to complete the brake bleeding process.
After driving for so many years, I've found that the most common reason for low brake fluid is a leak in the braking system. It could be due to a worn-out or broken seal in the brake caliper, or loose connections in the brake lines causing slow seepage. Sometimes, severe vehicle jolts or collisions can deform the lines, leading to leaks. Additionally, there's minimal evaporation loss during normal use, but it's rare and often just an excuse. I remember once when I was on a road trip, the brakes felt incredibly soft halfway, and upon pulling over, I found the reservoir nearly empty—scared me enough to rush to a repair shop. Running out of brake fluid makes braking unreliable, which is extremely dangerous, especially on highways. I recommend checking the fluid level under the hood during every maintenance service. For those with newer cars, pay attention to sensor alerts, but don’t wait for the warning. If you notice it's low, top it up promptly and ideally get a professional inspection to fix any leaks.
