Can Overheated Brake Discs Be Rinsed Directly with Water?
2 Answers
Overheated brake discs should not be rinsed directly with water. Reasons why water should not be used to cool overheated brake discs: When brake discs are in a high-temperature state, using cold water to cool them can cause the discs to crack suddenly due to the rapid temperature change, leading to the opposite effect. The cooling time of brake pads depends on various uncertain factors such as weather temperature, degree of overheating, and the material of the brake pads. Solutions for overheated brake discs: The primary method to reduce speed and cool the brake discs is to utilize the resistance of the engine at low speeds, with braking as a supplementary measure. This approach helps minimize wear on the brake pads and allows them to cool down over time.
During my previous self-driving trip in the mountains, the brake discs got so hot from continuous downhill braking that they started smoking. Thinking that splashing water would cool them down quickly, I tried it, but it resulted in slight warping and squeaking noises, almost ruining them. The mechanic told me that hot brake discs encountering cold water can cause thermal shock, leading to uneven internal metal stress, warping, or even cracking, which in severe cases might cause brake failure. Since then, I've learned to pull over for 5-10 minutes to let the brakes cool naturally with airflow while also checking the brake pad wear. If the pads are severely worn, I replace them promptly. The preventive method is to avoid continuous hard braking on long descents—instead, use engine braking by downshifting to slow down, ensuring safe and worry-free driving, which saves both hassle and money.
