Brakes are your vehicle's most important safety system. Under normal conditions, a driver exerts about 70 pounds of force on the brake pedal (about the same amount of effort it takes to bite into a steak) to bring thousands of pounds of moving metal and plastic to a quick and controlled stop. A flawless brake system is absolutely crucial to driver, passenger and pedestrian safety.
Read on to learn how a modern automotive brake system works and some of the most common brake system problems.
When you press the brake pedal, the brake linkage (rod) pushes on the master cylinder's internal piston seals, pressurizing and forcing brake fluid into the brake lines, brake calipers and wheel cylinders. This causes the brake pads to press inward against the rotors and force the brake shoes to press outward against brake drums.
Brake boosters assist drivers by multiplying the force they apply to the brake pedal. These boosters use engine vacuum, an electric pump (diesel engines produce little or no engine vacuum) or hydraulic pressure (usually the pressure of the power steering pump). This increases braking performance while decreasing pedal effort, making driving safer and more pleasurable.
Made of double-walled steel and multi-layer rubber and synthetic compounds, brake lines and hoses transfer pressurized fluid from the master cylinder to the brake wheel assemblies.
A disc brake assembly consists of a brake caliper, brake pads, disc rotor and mounting hardware.
A drum brake assembly consists of a backing plate, wheel cylinder, brake shoes/linings, hold-down and pull-back springs, brake drum and an automatic self-brake adjusting mechanism.
Modern brake systems include a brake warning lamp switch that tells the driver if the master cylinder is low on brake fluid, or there is a problem with the brake system. There is also a parking brake warning light that lets you know if the parking brake is engaged.
Applying the parking brake mechanically locks the rear brake assemblies to keep a car stationary when parked on a hill. It also helps stop a vehicle due to a hydraulic system failure.
A hybrid's hydraulic brakes includes all the same parts as a standard hydraulic brake system.
Hydraulic brake systems convert mechanical energy (the spinning wheels) into heat energy by transforming and amplifying the force exerted on the brake pedal. The brake pedal acts like a lever. Along with the brake booster, it greatly multiplies the force applied on the brake fluid in the master cylinder.
The master cylinder also increases brake fluid pressure, then sends pressurized brake fluid, via brake lines and hoses, to the brake calipers and wheel cylinders. The pressurized fluid acts on the caliper piston, squeezing the disc brake pads inward, clamping the pads against the brake rotors.
On drum brakes the wheel cylinders slide outward, forcing the brake shoes against the drum using a wedging, jamming action — similar to how a bicycle coaster brake works. The energy of the pads clamping against the rotors and brake shoes pushing against drums generates friction and heat. This heat-friction, along with friction generated between the tire and road surface, slows rotor and axle (and wheel) rotation and ultimately brings the car to a stop.
On a regenerative braking system, stepping off the accelerator or pushing on the brake pedal causes a hybrid car's electric drive motor to run backward. The drive motor spinning backward places a drag on the wheels and slowing the car, while also producing electricity that recharges a hybrid's high-voltage batteries. While regenerative braking provides practically all the initial stopping power, the hydraulic system engages during panic stops or hard stopping at high speeds.
A regenerative braking system has a unique pedal feel but can exhibit all of these same symptoms.
Brakes are one of your car's most essential safety systems. Never dismiss a brake warning light or brake system problems. Disregarding brake issues can be dangerous and lead to much more expensive repairs. When it comes to your car's brakes, it's always better to be safe than sorry.
2024-03-16T17:48:11Z dg43tfdfdgfd