Braking Systems

Even a car with a functional braking system requires lots of distance to stop.

Explanation Video

Brake System Components Master Cylinder Brake Fluid Vacuum Booster (optional) Proportioning Valve Brake Lines (steel and flexible hose) Drum Brakes Disk Brakes Parking Brake ABS Brakes Diagnosing Brake Problems video

Master Cylinder When the brake pedal is depressed, the master cylinder forces fluid to each of the vehicle's wheels.

Brake Fluid transmits pressure and motion in the brake system. 2 types of brake fluids: – glycol – silicone

Brake Booster A power-assisted brake system uses engine vacuum to add pressure to the master cylinder.

Hydraulic Lines Metal Brake Lines and Flexible Brake Hoses - connect the master cylinder to the wheel cylinder at each wheel.

Drum Brakes

Wheel Cylinder pressure from the master cylinder causes the wheel cylinders to press outward against the brake shoes.

Brake Shoe Brake shoes expand against the inside surface of the brake drum. The friction between the stationary shoes and the revolving drums causes the drums to stop the wheels.

Disk Brakes similar to the brakes on a bicycle. Pressure on the caliper squeezes a friction pad against the sides of the wheel, slowing the bicycle.

Rotor and Caliper Friction between the stationary brake pads and the spinning brake rotor cause the rotor and wheel to slow and stop. How Disk Brakes Work Video

Parking Brake Pulling handle will activate brake drum with levers and cables, locking the wheels in one place. Correct use of parking brake video How it works video

Anti-Lock Brakes Uses speed sensors to detect when a wheel stops turning and uses the computer to pulse the fluid flow to that wheel cylinder. Explanation Video Troubleshooting Video Troubleshooting Video

Annual Inspection The brake system should be inspected by a qualified mechanic once a year for: – lining wear, – brake fluid leakage, – brake disc thickness variation, – broken seals How to tell when disk brakes are badly worn video