Brake Fade: What It Is and How to Avoid It
Brake fade is a temporary loss of braking performance caused by the brakes overheating, usually from long, continuous braking such as a heavy descent. The pedal can feel soft or the car stops less well. You avoid it by using engine braking in a low gear, braking firmly then releasing, and keeping the brake fluid fresh.
What brake fade is
Brakes work by turning the car's movement into heat through friction. Normally that heat dissipates fine, but under prolonged heavy braking, such as a long downhill, the brakes can get so hot that they temporarily stop working as well. That is brake fade.
You feel it as the pedal going softer, the car taking longer to slow, or needing more pedal pressure for the same effect. It is usually temporary and recovers once the brakes cool, but it is alarming and dangerous when it happens.
What causes it
Fade comes from heat building up faster than the brakes can shed it. The main causes are long, continuous braking, especially descending a long hill, and a heavily loaded car or one towing, which puts more demand on the brakes.
The brake pads, discs and fluid all have temperature limits; exceed them and performance drops. Old, moisture-laden brake fluid is a particular risk, as the moisture can boil and create compressible vapour, giving a soft pedal, sometimes called vapour lock.
How to avoid it on long descents
The key on a long hill is to let the engine help rather than relying on the brakes alone. Change down to a lower gear so engine braking holds your speed, taking much of the load off the brakes.
- Select a low gear before and during a long descent.
- Brake firmly for a moment, then release, rather than riding the brakes continuously.
- Keep your speed sensible so you are not constantly braking hard.
This lets the brakes cool between applications instead of overheating.
Why riding the brakes is worse
It seems intuitive to gently hold the brakes all the way down a hill, but this is exactly what causes fade. Continuous light braking keeps the brakes working without ever letting them cool, so heat builds steadily.
The better technique, firm braking then releasing, slows you effectively while giving the brakes brief moments to shed heat. Combined with engine braking in a low gear, it keeps temperatures down and the brakes working properly all the way down.
The role of brake fluid and pads
Your brakes' resistance to fade depends partly on their condition. Old brake fluid that has absorbed moisture boils at a lower temperature, making fade more likely, which is why most makers recommend changing it every two years.
Worn or poor-quality pads and discs also cope less well with heat. So keeping the fluid fresh and the pads and discs in good order, both checked at a brake fluid change or service, gives the best protection against fade.
When fade is a warning
Occasional fade from genuinely extreme use (a long alpine descent, say) is a physics issue managed by technique. But if your pedal feels soft or fades in normal driving, that is a warning of a fault, such as old fluid, worn pads, or a hydraulic problem, and needs checking.
A soft or sinking pedal should never be ignored. We offer free visual brake checks and can test the fluid and inspect the pads and discs, so your brakes are reliable when you need them most.
Frequently Asked Questions
What is brake fade?
Brake fade is a temporary loss of braking performance caused by the brakes overheating, usually from long, continuous braking such as a heavy descent. The pedal feels softer or the car stops less well. It usually recovers once the brakes cool, but it is dangerous when it happens.
How do I avoid brake fade on a long hill?
Change down to a low gear so engine braking holds your speed and takes load off the brakes, brake firmly then release rather than riding the brakes continuously, and keep your speed sensible. This lets the brakes cool between applications instead of overheating and fading.
Why is riding the brakes downhill bad?
Continuously holding the brakes keeps them working without ever cooling, so heat builds steadily until they fade. Firm braking then releasing slows you effectively while giving the brakes brief moments to shed heat. Combined with engine braking in a low gear, it keeps them cool.
Does old brake fluid cause brake fade?
It makes fade more likely. Brake fluid absorbs moisture over time, and that moisture boils at a lower temperature, creating compressible vapour that gives a soft pedal under heat, sometimes called vapour lock. Changing the fluid every two years, as most makers advise, reduces the risk.
My brake pedal feels soft in normal driving - is that fade?
A soft pedal in normal driving is more likely a fault than true fade: old fluid, worn pads, air in the system or a hydraulic problem. It should never be ignored, as it reduces braking. Have it inspected promptly; we offer free visual brake checks and can test the fluid and components.
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Hero image: “IMG_1625 1967 Buick Special” by Rojer (source), licensed under CC BY.