Brake Fade: The Heat Failure

Braking converts motion into heat (Module 4's whole premise). The friction surfaces are built to run hot — but past their design temperature, friction falls: the pedal still moves, the parts still clamp, and the car barely slows. This is brake fade, and its signature is deceptively gentle — a pedal that feels normal-to-soft while doing less and less.

Fade is a sustained-load failure, which is why it belongs to one scenario above all: the long descent. The escarpment stretches — Kikuyu–Naivasha on the old road, Limuru, Mau Summit, Kerio Valley — are where a loaded vehicle riding its brakes downhill for ten minutes feeds in heat faster than discs (and especially drums) can shed it.

The defence is Lesson 1.11's rule, mechanism now visible: engine braking. A lower gear makes the engine absorb speed continuously, so the brakes are used briefly and intermittently — staying inside their heat budget for the moment they're truly needed. The rule of thumb: descend in the gear you'd climb in. Riding the pedal down an escarpment isn't a style choice; it's spending a finite heat budget on nothing.

If fade begins (pedal working, car not slowing): drop gears immediately — forcefully if needed — get off the brakes to let them cool, and take escape options early (climbing lanes, verges) rather than hoping the last of the friction holds.