Why Do Drum Brakes Lock Up When It Rains?
2 Answers
Introduction to the reasons why drum brakes lock up after rain: Because the brake shoes inside the wheel hub get wet, after parking and pulling the handbrake, over time, the brake disc friction pads will rust and stick together. The longer the time, the tighter the adhesion. If the car's brakes lock up on rainy days, you can repeatedly move forward and backward about three times. If this doesn't work, pour 100°C boiling water on the brake pads and then repeat the previous method. The brake pads and brake drum will expand due to heat and automatically separate. For rear wheel lock-up situations, the solutions are as follows: 1. Start the car, release the handbrake, and engage 1st gear/R gear: When the brake disc adhesion is not too strong, this method usually solves the problem easily, but it will cause wear to the tires. 2. Use 100°C boiling water: Pour it onto the brake pads, then repeat the first method. The brake pads and brake drum will expand due to heat and automatically separate. 3. Loosen the tire bolts: Remove the tire and tap the brake drum.
On rainy days, drum brakes are prone to locking up mainly because rainwater seeps into the brake drum, making the friction linings slicker and reducing friction. Having driven for many years, I often encounter this issue. Especially after rain, if not dried promptly, water accumulates inside the brake drum, causing the brake shoes to stick together and the wheels to lock. This is different from disc brakes, which have ventilation designs that prevent water accumulation. Drum brakes, however, are like enclosed boxes where water doesn’t drain easily. I remember last time it rained, my wheels suddenly locked when I braked—it was terrifying. Since learning to drive, I’ve made it a habit to inspect the braking system before the rainy season, especially the drum brake components, by disassembling and cleaning them to ensure no rust is present. I also drive slower in the rain and avoid sudden braking. Without regular maintenance, rust can make sticking more frequent, so periodic upkeep is crucial.
