Braking systems are one of the most vital safety systems in our vehicles. They are often taken for granted, but when it is vital to stop a vehicle to avoid an accident, we realize the value of our brakes.
The Basics
Brakes use friction to stop our vehicles. There are a few types of braking systems: disc brakes, drum brakes, and regenerative brakes. Anti-Lock braking technology adds additional safety to braking systems.
Disc brake systems
- When a brake pedal is pressed, the vehicle uses the master cylinder to apply hydraulic pressure through the brake lines to the brake pistons.
- The pistons apply pressure to the brake pads causing them to squeeze a metal disc called a rotor to create enough friction to slow or stop the vehicle.
- In older vehicles, it is common for disc brakes to be on the front wheels with drum brakes on the back wheels. While in newer vehicles, the disc brakes are on all four wheels.
- The brake pads are the main item that wears out, but the surface of the rotors may need to be machined to ensure a flat surface for the pads to apply friction.
Drum brake systems
- Drum brakes work in a similar fashion to disc brakes by applying friction between a brake shoe and a brake drum to create the force necessary to stop a vehicle.
- Drum brakes are usually only found on rear wheels of vehicles.
- The main wear item is the brake shoes, but the brake drums may need to be machined to ensure a flat surface for the shoes to apply friction.
Anti-Lock braking technology
With today's technology, cars have anti-lock brakes to keep them from skidding. In addition to the mechanical parts of the brake systems described above, the car has an electronic system that measures the speed of the wheels in conjunction with one another and can determine if the car is skidding or dragging. If one wheel is spinning at 20 mph and one is at zero, the car releases the brake on the wheel that is going zero and pulses it to keep the car from going into a skid.
Regenerative brake systems
- Regenerative braking systems are found in electric hybrid vehicles like a Toyota Prius and electric vehicles like a Tesla Model 3.
- They slow a vehicle down by applying the forward motion of the vehicle to turn the electric motors in reverse to reclaim the energy. This causes enough friction to slow or stop the vehicle under some circumstances.
- Regenerative brakes use a brake controller integrated with anti-lock braking systems to provide determine when to use the regenerative brakes and when to apply the friction brakes.
- As regenerative braking systems mature, friction brake systems become less necessary and last a much longer amount of time.
Normal wear
The average life of a braking system can vary a lot based on driving habits and routines. When driving in town, brakes are needed to stop at traffic lights, slow for turns, and adjust speed for changing speed zones. If mostly driven in town, brakes will get more use than if driven mostly on the highway. Most manufacturers recommend inspecting the brake system every year or every 12,000 miles.
Brake inspections is advised if:
- A grinding or squealing noise is heard when the brake pedal is pressed.
- The pedal goes too far toward the floor, or farther than normal.
- The car skids to one side.
- The car takes longer to stop than expected.
- A warning light is lit on the dashboard.
Care and maintenance
Brakes are critical to vehicle safety on the road, so it is important to ensure that they are working correctly. To ensure safety, your auto care team should follow these simple steps.
- Inspect brake pads and shoes for wear on a yearly basis.
- Make sure there are no leaks in the hydraulic system.
- Test brake fluid. Copper can get into brake fluid from the brake lines. If it does, the brake fluid will not work correctly.
