Is It Normal for Brakes to Lock Up on Rainy Days?

[Elijah]

It is normal for car brakes to lock up on rainy days. You can try repeatedly moving forward and backward about three times. If this doesn't work, you can pour 100℃ boiling water onto the brake pads and then repeat the previous method. The brake pads and brake drum will expand due to heat and automatically separate. Alternatively, you can remove the tire and tap the brake drum to loosen the adhered brake shoes and drum inside. Below is some relevant information about brake lock-up: Solution: Use ABS (Anti-lock Braking System) technology. The main feature of this technology is that during emergency braking, the wheels do not stop rotating, ensuring that the vehicle does not experience sliding friction with the ground. This helps maintain vehicle control and prevents tire blowouts due to sliding friction. ABS Anti-lock Principle: The ECU (Electronic Control Unit) controls the ABS actuator to increase, maintain, or reduce the brake fluid pressure for each wheel. Each wheel is equipped with a speed (vehicle speed) sensor that sends the wheel's speed signal to the ECU. If excessive braking force risks causing wheel lock-up, the ECU sends a signal to the ABS actuator to reduce brake fluid pressure. Once the nearly locked tire is released from braking, it naturally regains traction control.

[Owen]

A few days ago, I just helped my neighbor deal with abnormal braking issues in the rain. Brake lock-up during rain is not normal—it’s mostly because the ABS anti-lock braking system isn’t working properly. Rainwater makes the brake discs slippery, and the ABS should rapidly pulse the brakes to prevent tire lock-up. If you feel the tires locking up and skidding, it’s likely that the wheel speed sensor is clogged with mud or water. I once encountered this situation after driving in the rain and was so scared that I immediately eased off the brakes and slowly pulled over. It’s recommended to check the brake discs and sensors right after rain. Prolonged lock-up can severely wear out tires and brake pads, or even cause loss of vehicle control—so don’t take it lightly.

[HarmonyRose]

As a long-distance driver who's been on the road for years, I've seen plenty of cases of brake lock-up in rainy weather. This is definitely abnormal and often serves as a warning from the braking system. The most common causes are seized caliper pistons or water contamination in the brake fluid. I remember one heavy rain when I was driving a friend's car - the right front wheel suddenly locked up, and we later found out it was due to rusted and stuck calipers. If this happens, never slam on the brakes. Instead, use gentle pumping to gradually reduce speed. I recommend having mechanics check the brake fluid's water content during every maintenance service - if it exceeds 3%, it's time for a replacement.

[SanDante]

During driving school, the instructor repeatedly emphasized the need for extra caution when braking in rainy conditions. If wheel lock-up occurs, it may indicate ABS failure. Rainwater drastically reduces tire grip, and a properly functioning ABS should produce a tapping sensation underfoot. If the entire vehicle slides forward, it's likely due to a sensor malfunction or wiring short circuit. Once after washing my car, I noticed the warning light came on, and it turned out to be a loose wheel speed sensor connector. Such issues require specialized diagnostic tools to read fault codes - DIY attempts might worsen the situation, so it's best to visit a professional repair shop.

[StIsaac]

Master Wang from the repair shop mentioned that brake locking in rainy weather is mostly caused by the caliper rusting, which prevents the piston from retracting, or the brake pads wearing unevenly and getting stuck. Last time, the right rear wheel of my car locked up due to a rusted caliper, and the tire even smoked while being towed. A simple way to check is to feel the temperature of the wheel hubs after driving—the one that's unusually hot definitely has an issue. Now, I regularly perform brake maintenance, especially stepping on the brakes a few more times after rain to evaporate moisture. This problem really shouldn't be delayed; replacing a set of brake pads is definitely cheaper than reinstalling the suspension, right?