What are the reasons for sudden brake failure when driving downhill?
2 Answers
There are several reasons for sudden brake failure when driving downhill: 1. Wear of brake pads and brake discs: The wear of brake pads and brake discs leads to thinning of their thickness. For example, in disc brakes, the caliper clamps the brake disc for braking over a long period of time. Over time, friction causes the surfaces of the caliper and brake disc to become thinner, which increases the travel distance of the brake pedal. 2. Issues with brake fluid: Most vehicles use hydraulic braking systems, which require brake fluid to pressurize and transmit braking force to the brake pads. 3. Tire wear: The lifespan of tires is generally around 60,000 kilometers. As tires approach the end of their lifespan, the tread becomes very thin, and the adhesion between the long-term friction-worn tires and the road surface deteriorates, leading to an increase in braking distance.
I have driven in mountainous areas for decades and encountered sudden brake failure on downhill slopes several times. Common causes include brake fluid leakage leading to insufficient hydraulic system pressure; or frequent braking on downhill slopes causing overheating and fade of friction pads; blocked or ruptured brake lines are also common issues; air intrusion into the brake system causing vapor lock; and poorly maintained vehicles with excessively worn friction pads can also lead to failure. I recommend car owners check brake fluid levels before long trips, avoid continuous braking on steep slopes, and use engine braking to assist in reducing risks. Regular maintenance can effectively prevent these troubles, especially for older cars, which have greater hidden dangers—safety should always come first. Driving requires caution, as lives are at stake.
