What to Do If the Brakes Become Soft After Bleeding the Air?
2 Answers
First, have one person pump the brakes 4-5 times. Then, have another person loosen the bleeder screw on the brake caliper. If there is indeed air in the brake lines, a mixture of brake fluid and air will be expelled. Repeat the above steps until only brake fluid is expelled, indicating that all air has been removed from the brake lines. Finally, tighten the bleeder screw to complete the process.
I've encountered this issue before. After replacing the brake fluid and bleeding the system myself, the brake pedal became spongy within a few days. I think the possible causes could be incomplete air bleeding or a minor leak in the system. I remember after finishing the job last time, during testing I noticed the brake fluid reservoir level was dropping quite quickly. Upon closer inspection, I found leakage traces at the front wheel caliper connection point due to aging. I immediately drove the car to a roadside repair shop, where they diagnosed a failed seal ring after inspection - replacing the part and re-bleeding solved the problem. If you have some knowledge, you can do simple checks: without starting the engine, pump the brake pedal several times to see if it sinks too quickly (indicating a problem); then visually inspect brake fluid level and look for oil stains near wheels. Safety first - don't delay if you notice abnormalities, seek professional help immediately to prevent accidents. During routine maintenance bleeding, be thorough to ensure complete air removal from every wheel.
