Brake fade on a long descent with a full load
You are driving a fully loaded seven-seater down a long, steep, winding road on a hot afternoon. The descent is about 2 km. For the first kilometre you have held the footbrake almost continuously to keep the car at 40 km/h. The pedal now feels soft and travels noticeably further before it bites, and there is a hot, acrid smell. The gear selector has a '2' position below 'D'. There is a car 15 m behind you and the road has a barrier on the outside of each bend.
1. What is happening, and why does it get worse the longer you hold the brake?
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This is brake fade. Continuous light application overheats the discs and pads, the friction material's effectiveness drops, and the brake fluid can boil, putting gas into the hydraulic line. A soft, long pedal is the classic signature.
It is self-worsening:
- A long, light drag generates heat continuously but gives the brakes no interval in which to shed it to the airflow.
- The hotter they get, the less braking force the same pedal pressure produces, so the driver instinctively presses harder and adds more heat.
- The result is that your braking is weakest at the bottom of the descent, exactly where speeds are highest and the bends are taken fastest.
Load matters: a fully loaded car carries proportionally more kinetic energy into every bend, and the same brakes have to dissipate all of it.
2. What should you do now?
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Get off the footbrake.
- Select '2' so engine braking holds the descent and the brakes get cooling intervals.
- Use the brakes in short, firm applications separated by gaps, not a continuous drag.
- If the pedal continues to sink, pump it to rebuild pressure, use the handbrake progressively (never snatched, or the rear wheels will lock), switch on hazard lights, sound the horn and look for a run-off or a widening in the road.
- Do not switch the engine off - you would lose power assistance for both steering and brakes.
Do not simply ride the brakes to the bottom hoping they recover; they will not recover while they are still being worked.
3. The car behind is 15 m back and closing as you slow. How does that change your plan?
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It changes the order of what you do, not the objective.
- Signal early, then tap the brake pedal a few times to show stop lights before any meaningful deceleration - the driver behind must see you slowing before you actually slow.
- Use the lower gear so the deceleration is gradual and the brake lights are not the only cue.
- Increase your gap to whatever is ahead so you never need a sudden stop.
If the car behind does not respond, do not let it dictate your speed. Fading brakes on a 2 km descent are a far greater hazard than a low-speed rear-end shunt. Pull into the first safe lay-by or widening, let the car pass, and let the brakes cool before continuing.