What happens when using the service brake continuously on a long slope?

[VivianDella]

Continuously using the service brake on a long slope can lead to the following situations: the temperature of the brake increases, causing a sharp decline in braking effectiveness. It can also cause the brake pads to overheat, resulting in reduced braking force. In severe cases, it may lead to a complete loss of braking ability, causing brake failure. Therefore, when descending a long slope, it is advisable to use a lower gear and employ engine braking. If you can clearly feel severe malfunction symptoms in the car, for the safety of both the passengers and the vehicle, it is recommended not to continue driving. Brake system failures are usually accompanied by symptoms such as brake failure, poor braking, brake pulling, or uneven braking. Without effective braking, there is no safety guarantee, and immediate inspection and repair are necessary.

[EmmaRose]

Oh my, let me tell you, never keep stomping on the brakes continuously when driving down long slopes! I learned this the hard way last time on a mountain road. At first, the brakes worked fine, but the more I pressed, the softer they became—the pedal almost went to the floor with no stopping power, and my back was drenched in cold sweat from fear. When I stopped and touched the wheel hubs, they were so hot you could fry an egg on them. The mechanic said the brake pads had turned blue from overheating. I’ve since learned my lesson—now, on long descents, I shift to manual mode early and use engine braking to control speed. If you’re driving a manual transmission car, shifting to third gear works wonders. If you must use the brakes, do it intermittently (pump them) to give the pads time to cool. Oh, and a heads-up: the trick of spraying water on the brakes is for big trucks—don’t try it with your family car!

[AlainaFitz]

Continuously braking on long downhill slopes is indeed dangerous. I have identified three key issues: brake pads experience thermal fade due to high temperatures, reducing the friction coefficient by over 50%; brake fluid boiling creates vapor lock, making the pedal soft or even causing complete loss of braking; in severe cases, it may lead to brake hose rupture. Last year, I personally tested this - after continuous braking for ten minutes, the brake disc temperature exceeded 600°C. The safest approach is to downshift in advance: automatic transmissions should switch to manual mode and lock in third gear, while manual transmissions should directly downshift two gears. It's best to pull into an emergency stopping area every two kilometers to cool down. Remember to regularly check brake fluid moisture content - replacement is mandatory if it exceeds 3%.

[OBennett]

Last week, I encountered this exact situation while driving my family through mountain roads. At the start of the 5-kilometer long descent, the brakes were still responsive, but halfway down, I clearly felt the pedal travel getting longer, and a burnt smell filled the cabin. When I stopped to check, I found the brake discs glowing red and smoking, with the wheel hub covers even warped from the heat. Later, it cost me over 800 yuan to replace the brake pads. Now, here's how I handle mountain descents: slow down to 40 km/h before the descent, shift to L gear for automatics, or third gear for manuals. Every five minutes, I pull over at a scenic spot to let the brakes cool and check tire temperatures. A special reminder for EV owners: don't rely too much on regenerative braking on long descents—mechanical brakes are essential when needed.

[SanCaleb]

Calculating from the perspective of vehicle wear: Continuous braking for ten minutes can cause the brake pads to exceed 500 degrees, leading to surface hardening and cracking. A repair case I handled showed that brake pad wear after a long downhill stretch was equivalent to 300 kilometers of normal driving. Even more troublesome is that high temperatures can cause brake fluid to vaporize, with repair costs starting from five to six hundred yuan. It is advisable to check the brake condition before descending and maintain a speed below 60 km/h. For automatic transmissions, use S or L gear, while manual transmissions should downshift for speed control, which is three times more efficient than braking. Stopping every three kilometers to cool down for five minutes can effectively protect the braking system. Keeping a bottle of water in the spare tire well can be used to cool the brakes in an emergency.