Why Do Brakes Lock Up?
2 Answers
Brake lock-up can occur due to the following reasons: 1. The master cylinder rubber cup is stuck and fails to return to its original position; 2. Issues with the fit between the master cylinder rubber cup and the master cylinder inner diameter; 3. The brake piston fails to return or returns poorly; 4. Insufficient rigidity of the brake disc. When the braking system is used frequently, the brake disc may deform under high temperatures due to insufficient rigidity, leading to wheel lock-up during subsequent use. Brake lock-up refers to the situation in vehicles without ABS (Anti-lock Braking System) where the driver forcefully presses the brake pedal while driving, causing the wheel speed to rapidly decrease. When the braking force exceeds the friction between the wheel and the ground, the wheel locks up. The consequences include reduced friction between the tire and the ground, leading to dangerous phenomena such as skidding, fishtailing, and sudden spinning.
Last time my car slid over ten meters when I braked hard in the rain. Later, mechanic Lao Li said the brake lock-up was mainly due to the caliper piston rusting and seizing. Especially in northern winters when de-icing agents are used, brake fluid absorbs moisture and corrodes metal components. If the piston gets stuck in the caliper, it can lock onto the brake disc. Additionally, swollen or deformed brake hoses and blocked lines can easily cause one wheel to brake too hard. If you feel the steering wheel suddenly pull to one side during hard braking, it's likely a single-side lock-up - you should immediately ease off the brake slightly and correct your steering. It's best to check the lubrication of caliper guide pins during seasonal maintenance, as rusted metal components are no small matter.
