Noun
brake fade (uncountable)
(automotive, rail transport, mechanical engineering) Partial or total loss of braking force with prolonged continuous or repetitive application of a heavy vehicle's brakes, due to the effects on the brake system of the heat generated by heavy braking.
To help prevent a runaway caused by brake fade, heavy trucks are required to stop at the top of the downgrade to give their brakes time to cool.
Brake fade is not always due to overheating. Source: Internet