Brake fade is when the brakes become less and less responsive during repeated heavy braking.

Brake fade is caused by heat within the brake system. This can cause the brakes to become less effective in several ways:

• the lining material on the brake pad (or shoe in a drum brake) can overheat, causing it to lose its friction properties
• the pad material can vaporise, and the gas produced can be trapped between the pad and disc
• the brake fluid can become hot enough to boil
• contaminants in the brake fluid, such as water, can become hot enough to boil

Fade can be avoided by improving brake cooling. Cool air can be ducted to the brakes and the wheels can be shaped to extract hot air. Discs can be internally ventilated to keep the temperature of the working surface cool. Grooves or drillings can be added to discs to remove vaporised pad material.

Brake fade is usually temporary – the brakes will regain all or most of their effectiveness is allowed to cool.

If brakes fade in use the driver needs to react quickly:

• use engine braking to slow the car, by selecting the lowest gear possible
• avoid using the brakes as much as possible, to give them time to cool
• do not stop the car except in an emergency – it is better to keep the car moving to provide a cooling air flow