Most everyone uses their brakes incorrectly.
OK, that's a bold statement, and
it does matter what your priorities are. When I transported my elderly and infirm parents and in-laws, I used my brakes incorrectly, too. Their comfort meant more to me than brake life. Obviously, when coming down the mountain with a trailer load, or in an emergency, or driving on wet/icy/gravel roads, you don't have a lot of options--you're going to brake however you need to to get stopped.
Ideally, when there is a choice, to maximize brake life, the faster you go, the harder you stop. As your speed reduces, particularly below 15--20 mph, you begin releasing pedal pressure. As the vehicle comes to a stop, you're releasing even more pressure. The suspension returns to near-normal height in front just as the vehicle stops.
While stopped, you're holding only as much pressure as it takes to remain stopped--you're not hard on the pedal.
WHY:
- The rotors are vented. Drums usually have fins cast into them. Rotors and drums are designed to get hot, They're also designed to move cooling air.
- The pads/shoes are insulators in addition to being friction material
- Brake fluid (especially old fluid) expands when hot, potentially boiling if it's absorbed water.
- Most brake fluids LOVE to absorb water
- The most-contaminated fluid is usually in the wheel cylinders/calipers.
- Wheel cylinders including calipers have rubber parts in them, wheel cylinders do better if they don't get overly-warm.
SO:
Vented rotors are essentially centrifugal air pumps. The faster they spin, the more cooling air they move. At low speed, they don't move much air. Braking hard at high speed creates heat, but the rotor is turning fast and pumping lots of cooling air. The rotor gets hot, which is fine. It's designed to get hot. The cooling air carries away the heat, and everything is good.
The pads get hot on the surface that contacts the rotor. Pads are designed to take some heat. "Street" compound friction material works good when cold, better when warm, and not so good when really hot. "Racing" pad material works better when hot, but doesn't really apply to street-driven vehicles.
If the pads stay in contact with a hot rotor, eventually they get hot
all the way through, and then they transfer heat to the caliper.
The caliper transfers heat to the fluid. Bad things happen then.
Use the brakes harder when there's more cooling airflow. DON'T glide to a stop with the brakes applied gently for a long time; that gives heat time to travel through the brake pad and warm the caliper and fluid.
And don't clamp the pads tighter than needed to the hot rotor when stopped, for the same reason. HOT friction material can actually transfer to the HOT iron--rotor or drum. Then you have brake pulsing until it wears off again.
Get ON the brakes, and then get OFF the brakes. The point is to
let the iron (rotor and drum) get hot while they're still turning fast enough to pump air, while minimizing the temperature and time-at-temperature of the pad, caliper, and fluid. It makes more difference with disc brakes, but it's worthwhile on drums, too.
Folks will ***** that you're trying to "throw them through the windshield" and "you're really hard on your brakes". In fact, your brake linings will last longer. Taking a long time, braking
too gently, is what's hard on brake linings and brake fluid. You put a lot of heat into the rotor when it's turning too slow to pump cooling air; and you brake for a long time so that heat travels through the pad into the caliper and fluid.
