Brake Fade on a Loaded Van Descending a Pass
You are driving a 3.5-tonne panel van loaded to its permitted maximum with 800 kg of ceramic tiles. The route descends a mountain pass: 6 km of continuous 8% gradient with three hairpin bends. The outside temperature is 31°C. After 3 km the brake pedal feels spongy and travels closer to the floor. A hot, acrid smell enters the cab, the ABS warning lamp illuminates, and the handbrake lever has four clicks of travel; it was last adjusted 10,000 km ago. Your speed is 55 km/h in fourth gear. A lay-by is 200 m ahead on the right. On the left is a steep drop with no barrier. A car is close behind. The engine temperature gauge is normal, the fuel gauge shows a quarter tank, and you need to stop safely.
1. Diagnose what is happening and rank the immediate risks.
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The symptoms point to brake fade: heat from the 8% descent has overheated the pads or discs, or boiled the fluid, so pedal travel has increased and stopping power has fallen. The acrid smell supports overheated friction material. The ABS lamp may be a wheel-sensor fault, low fluid or the start of a hydraulic problem - do not assume ABS will save you. Four clicks on the handbrake means little reserve. The risks, in order, are total brake loss on a hairpin, then the close-following car, then the unbarriered drop on the left. Reduce speed now rather than waiting for the lay-by.
2. Describe the sequence you would use to slow and stop.
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Ease off the accelerator; do not coast in neutral. Change down from fourth to third and then second, letting engine braking slow the van. Apply firm, steady pressure to the pedal; if it sinks, pump it once or twice only if that restores pressure, but do not ride the brakes. Switch on hazard lights early to warn the car behind. Aim for the lay-by 200 m ahead, using the engine and a light, progressive handbrake application to trim speed. If the pedal goes to the floor, use the handbrake gently and look for a safe runoff; sound the horn on blind bends. Stop well into the lay-by, away from the drop.
3. What checks and decisions follow once you have stopped?
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Chock the wheels, let the brakes cool and do not pour water on hot discs. Check brake-fluid level and colour, look for leaks at the wheels and inspect pad thickness if visible. A spongy pedal, hot smell and ABS lamp are not defects to “drive out”; the van should not continue down the pass until a mechanic has checked the braking system. Arrange recovery, or move only to a nearby garage if the brakes are proven sound. If no lay-by had been available, I would have selected a lower gear much earlier, kept hazard lights on and looked for a wider verge or uphill escape rather than continuing at 55 km/h.