ABS

 
History
How it works
Effectiveness
Components
Q&A
Warning Signs
Problems






Brakes

Auto BrakesLet's start with the individual components of automobile brake systems. Automobile brake systems have three main segments: hydraulics, friction and mechanical components. Here's a brief description of the various components.

Hydraulics Master Cylinder

When you push on the brake pedal, pressure is created in the master cylinder which forces fluid out to the wheels.

Brake Lines & Hoses

Brake fluid travels through steel lines and high-pressure rubber hoses.

Brake Calipers & Wheel Cylinders

Located at each wheel, the pressurized fluid causes these devices to force the friction material against the drum and/or rotor to slow or stop the vehicle.

Friction Material Also called brake linings

These components are made of various heat-resistant materials that create the friction that slows or stops the vehicle.

Disc Pad

Used in a disc brake system; housed in a caliper and works with a rotor.

Brake Shoe

Used in a drum brake system; works with a wheel cylinder and drum.

Mechanical Components Hardware

Both disc and drum brake systems include various springs, clips and retainers to allow proper operation of the disc pads and/or brake shoes.

Shims

A backing for disc pads that is designed to minimize noise (squeal). Seal - Also known as a "grease seal," it shields the wheel bearing to keep out dirt and grit, which can cause bearing wear and failure.

Wheel Bearing

Allows the wheel and tire assembly to rotate smoothly on the axle spindle. Although not part of the brake system, these items are commonly serviced along with brake work. Most cars and light trucks. Does not include electronic ABS diagnosis or inspections that require in-depth analysis.

Datails

Disk Brake System
Disk brake systems work by using hydraulic pressure to press a pad against the rotor to slow the vehicle. When the brake pedal is pressed, it acts upon the piston in the master cylinder which sends pressure via the brake lines to the caliper. The pad-to-rotor friction stops the wheel from turning.

Rotor
The rotor is a circular plate that is gripped by the brake pads in order to slow the vehicle.

Brake Pad
The brake pad is friction material that is pressed against the rotor to stop the wheel from turning.

Caliper
The caliper holds the brake pads. It straddles the rotor and uses hydraulic pressure from the brake lines, along with internal pistons, to force the brake pads against the rotor.

Brake Pedal
The brake pedal works as a lever to apply pressure against the master cylinder.

Master Cylinder
The master cylinder moves brake fluid under pressure to the rest of the braking system.

Drum Brake System
Drum brake systems work by using hydraulic pressure to press a pad against the brake drum to slow the vehicle. When the brake pedal is pressed, it acts upon the piston in the master cylinder which sends pressure via the brake lines to the wheel cylinders inside the brake drum. The shoe-to-drum friction stops the wheel from turning.

Brake Drum
The brake drum is a heavy flat-topped cylinder, which is usually located between the wheel rim and the drive wheel. When the brakes are applied, the friction material of the brake shoes is forced into contact with the brake drum to slow the rotation of the wheels.

Wheel Cylinder
The wheel cylinder is a cylinder that contains pistons which use hydraulic force from the master cylinder to push the brake pads against the brake drum.

Brake Shoe
The brake shoe holds the brake lining and is used to force the lining against the drum when the brake is depressed.

Master Cylinder
The master cylinder moves brake fluid under pressure to rest of the braking system.

Brake Pedal
The brake pedal works as a lever to apply pressure against the master cylinder.