What is 'brake fade', and how can you prevent it when descending long, steep hills in Antigua?

1. When headlights dim during braking; replace the car battery
2. When brake fluid freezes in cold weather; add anti-freeze
3. When the brake pedal breaks off; use the door as an air brake
4. Loss of braking power caused by brakes overheating from continuous friction; prevent it by selecting a lower gear to use engine braking