What to Do When the Service Brake Fails While Driving Downhill?
2 Answers
When driving downhill, if the service brake (foot brake) fails, you can use engine braking to slow the vehicle down to a stop. In emergency situations, you can also bring the car to a halt by scraping against roadside obstacles to prevent more serious accidents. More details are as follows: 1. If the service brake fails, you can use the parking brake. It is best to use engine braking when going downhill. Parking brake braking refers to stopping the car using the handbrake. Here, it does not necessarily mean pulling the handbrake all the way; you can also slowly apply the handbrake to decelerate appropriately. 2. Engine braking involves lifting the accelerator pedal without depressing the clutch, utilizing the compression resistance, internal friction, and intake/exhaust resistance generated by the engine's compression stroke to create a braking effect on the drive wheels. Engine braking uses the engine's drag effect to slow the vehicle. The lower the gear, the more noticeable the drag effect and the stronger the braking. 3. When driving on long downhill roads, shifting to a lower gear and using the engine's drag effect can reduce the burden on the brakes and minimize the number of brake applications, preventing brake overheating and subsequent thermal fade. When driving on icy, snowy, or muddy roads, using engine drag braking can help prevent skidding.
I remember my palms were drenched in sweat the first time I experienced brake failure on a downhill slope. Never panic—engine braking is your best friend in this situation. Immediately shift to a lower gear: downshift manually for manual transmissions, or switch to L or M mode for automatics. While keeping the steering wheel steady, start pumping the handbrake—remember to repeatedly pull and release it instead of yanking it hard, as locking the rear wheels could cause a dangerous skid. Aim for roadside guardrails or mountain walls, intentionally letting the car’s side scrape against them to increase friction. Bushes and sandy areas also serve as natural deceleration zones. If all else fails, remember that hitting a guardrail is always better than plunging off a cliff. For routine maintenance, always ask your mechanic to thoroughly inspect brake lines and the booster pump—these are non-negotiable for mountain driving.
