What Causes the Spring Contraction Sound When Braking?
2 Answers
Braking with a spring contraction sound is a normal noise when the ABS is operating, so there's no need to worry. When the ABS system is active, the ABS indicator light on the dashboard will flash. Below is relevant information about the ABS system: The Anti-lock Braking System (ABS) consists of components such as the ABS module, ABS master cylinder, hydraulic pipes, and wheel speed sensors. During vehicle braking, it automatically controls the braking force to prevent wheel lock-up, maintaining a state where the wheels are both rolling and sliding (with a slip ratio around 20%) to ensure maximum traction between the tires and the road surface.
Last month, my brother's SUV also had this spring noise issue, so I specifically asked a repair shop mechanic. The clunking sound when stepping on the brake is mostly caused by the aging or deformation of the pedal return spring, especially common in vehicles over five years old. After prolonged use, the spring metal fatigues and makes abnormal noises due to friction when contracting, similar to the sound of bending an old ballpoint pen spring. Another possibility is a broken reset spring inside the brake light switch, which happens to be connected to the pedal. If you also notice the brake feeling softer or the pedal having more free play, it’s likely an issue with the push rod spring in the vacuum booster. Honestly, as long as it doesn’t affect braking performance, you can keep driving for now, but remember to have the mechanic inspect and replace the spring during the next maintenance—it only costs a few dozen bucks to fix.
