Brake fade on a steep descent with passengers

This is brake fade. Continuous use on a descent turns the brakes' energy into heat faster than the airflow can remove it. The pads and discs lose friction, and the fluid can boil, producing gas that compresses instead of transmitting force - hence the long pedal.

Why more of the same makes it worse:

• The pedal is the heat source. Holding it down on a descent keeps feeding energy into an already overheated system.
• Fourth gear gives you no engine braking. The engine is doing nothing to hold the vehicle back, so the entire job falls on the brakes, which are the part that has failed.
• Speed and heat feed each other. At 75 km/h the brakes have to shed far more energy per second than at 50, so the fade deepens as the speed rises.

Pumping can help if the problem is boiled fluid, because it may build pressure again - but it is a way of getting some braking back briefly, not a way of holding a steady speed down a hill.

1. Change down now - fourth to third, then second as the speed allows. Let the engine hold the vehicle. Do not worry about the noise or the revs; that noise is the braking you still have.
2. Build pressure with a firm, quick pump of the pedal, then hold steady pressure rather than stamping repeatedly.
3. Warn everyone: hazard lights on, horn, arm out of the window if useful. The lorry behind needs to know you are slowing and heavy.
4. Look for an escape before the bend, because the bend is where you will need steering and brakes at the same time: a gravel layby, a wide verge, a side road climbing away, a flat stretch.
5. Scrub speed deliberately if you must - steering along the rock face on the left to shed speed by friction is a last-resort, controlled act, chosen while you still have some steering, not after the bend has beaten you.
6. Use the handbrake progressively, not sharply. Snatching it will lock the rear wheels and spin a loaded minibus.
7. Do not switch off the engine - you lose whatever assistance you have left.

The order matters: gears first, because that is the only braking system still working, and route selection second, because you need to choose where you stop before you need to stop.

Passengers:

• Give one short, calm, repeated instruction: sit down, hold on, stay in your seats, doors stay shut.
• Stop people opening doors or moving about. A door opened on a bend at 75 km/h is a person on the road; weight shifting forward unbalances the vehicle exactly when you need it stable.
• Do not spend attention on explaining. Your attention belongs to the road, the gear lever and the escape route. The explanation can wait until the vehicle is stopped.

The lorry behind:

• Tell it you are in trouble: hazard lights, horn, arm out. A close following lorry that sees a problem can back off; one that assumes you are just slow will sit on your tail.
• Stopping dead on the bend is the worst outcome, because the lorry may not be able to stop behind you. If you can reach a wider stretch, a layby or the far side of the bend where you are visible, that is better than stopping where you are.
• Once stopped, get the vehicle off the carriageway if possible, keep the hazard lights on, get the passengers out on the side away from traffic, and do not continue the descent until the brakes have cooled and been checked - preferably not at all.