The brake system found in vehicles is designed to slow down and stop your vehicle. When the brake pedal is pressed the brake booster assists the master cylinder to apply enough force to move the brake fluid through the lines and hoses to the calipers which move the brake pads to squeeze the rotors. This action slows down and stops the vehicle. Each wheel on the vehicle has a caliper and rotor.
Types of brake systems
The brake system found in practically all cars today is a hydraulic brake system with disc brakes. Disc brake systems include calipers,brake pads,and rotors. In contrast,drum brakes have wheel cylinders,brake shoes,and drums. Drum brakes are rarely used on passenger cars these days. These systems use brake fluid to move the parts necessary to slow down and stop a vehicle. Here we will discuss the main parts of a disc brake system.
Components found in the brake system
- Brake pedal
- Brake light switch
- Brake booster
- Brake master cylinder
- Brake fluid
- Brake lines and hoses
- Brake calipers
- Brake caliper brackets
- Brake caliper bolts or anchors
- Brake pads
- Brake rotors
Brake Pedal
The brake pedal is the rectangular or square pedal next to the left of the accelerator pedal. This pedal is used by the driver to operate the brake system.
Brake Light Switch
This switch is often found mounted to the brake pedal. This switch closes when the pedal is pressed and completes the circuit to the brake lamps. The lamps are illuminated when this switch is closed.
Brake Booster
The brake booster is designed to assist the brake system to apply the brakes. The brake booster is found mounted on the firewall of the vehicle under the hood on the driver’s side of the engine compartment. The booster is typically round in shape and uses engine vacuum to operate. Some systems use power steering fluid instead of engine vacuum to assist the brake system. These systems are called hydroboost systems.
Brake Master Cylinder
The brake master cylinder holds the brake fluid for the brake system. This is where the brake fluid and level is checked. It is bolted to the brake booster. The master cylinder multiplies the force of the brake pedal and pushes the brake fluid through the lines and hoses.
Brake Fluid
Brake fluid is used to move the caliper pistons that move the brake pads to grab the rotors. Brake fluid has different ratings that indicate is boiling point. The rating of brake fluid is expresses as DOT 3,DOT 4,etc. Check with your vehicle manufacturer for the correct type of brake fluid to use in your vehicle.
Brake Lines and Hoses
The brake lines and hoses are the passages that the brake fluid moves through. These lines and hoses connect the brake master cylinder to the brake calipers. The lines are typically made of stainless steel and are attached to the body and frame of the vehicle. The brake hoses are used at the calipers because they can flex as the wheels turn and move up and down with the suspension.
Brake Calipers
The brake calipers hold the brake pads and apply the pads when the brake pedal is pressed. They fit over the rotor. When the fluid moves through the brake lines and hoses to the caliper the piston inside the caliper is pushed out by the fluid and forces the pads to grab the rotor to slow down the vehicle. When the brake pedal is released the caliper piston retracts and releases the brake pads.
Brake Caliper Brackets
The caliper brackets are bolted to the steering knuckle or spindle. They fit over the rotor. These brackets are made of steel or aluminum. They are what the brake caliper is mounted to and provide a seat for the brake pads.
Brake Caliper Bolts or Anchors
Caliper bolts or anchors attach the caliper to the caliper bracket. They are designed to let the caliper move when the brake pedal is pressed.
Brake Pads
The brake pads are the parts that grab the rotor to slow down the vehicle. Brake pads can be made from different types of material. This material is glued to a metal backing plate. The brake pads are designed to wear down and evenly. Brake pads are designed to be a maintenance item. This means that you will periodically have to replace them. This will be determined by your driving habits and quality of the brake pads.
Brake Rotors
Brake rotors are solid pieces of metal that are mounted to the wheel hub and turn with the wheel. The pads grab the rotor and slow down the rotation of the wheel. Brake rotors generally have slots between the inner and outer surfaces that allow the heat created by friction to dissipate quickly. Some brake rotors can be resurfaced or machined for a new flat surface when replacing the brake pads. Others need to be replaced when replacing the pads. Brake rotors have minimum thickness measurements that must be met in order to use them. If they are below this specification they should be replaced at all costs.