Power Brakes Versus ABS
Drum and Disc
- "Power" brakes use the vacuum created by your car's engine to drive pumps to either push brake shoes out against the inside of a drum rotating like your tires or clamp calipers against both sides of a disc that's spinning like your hubcap. Either way, it's friction that slows or stops the car.
What "Antilock" Adds
- A car equipped with ABS is still stopped by friction boosted by the engine's vacuum systems. Additional electronic controls "pump" the brakes---push the friction elements on and release them---faster and more effectively than any human. This means that brakes are less likely to overheat and the wheels won't lock and make the car skid.
Braking Without Power
- National Public Radio's "Car Talk" guys point out that power brakes, ABS or not, are most obvious when they're off, such as after the car has stalled. As in the days before power brakes, you'll have nothing but your own physical force transmitted to those drums or discs."You're going to have to stand on that brake pedal with both feet," Ray answered a questioner in 1992.