AUTOMOTIVE BRAKING SYSTEMS

Friction develops heat which absorbs kinetic energy of the car How it Works Friction develops heat which absorbs kinetic energy of the car

PURPOSE OF BRAKING SYSTEM Stop the vehicle by converting the kinetic energy of the vehicle to heat energy. Heat energy is created in the brakes by friction. Friction is created between a moving and a non-moving surface at each wheel to generate the heat. Disc and drum brakes are the most common type of braking systems used.

Factors Effecting Braking* Number of wheels braking. Weight of vehicle. Type of friction material. Surface area of friction material. Size or discs or drums Tire traction. Road surface. Load transfer. Incline or decline of road. (gravity) Engine braking. Pressure applied

Types of Braking Systems Service brakes. It’s the primary braking system using a the pedal connected to a hydraulic system causing it to operate. Parking brakes. It’s mechanically applied by a lever or pedal.

BASIC PARTS Pedal assembly Hydraulic system Power booster Disc brake assembly Drum brake assembly Parking brake BASIC PARTS

DISC BRAKES Disc brakes use a rotating disc with two stationary friction pads that are pressed against to rotor by the caliper to create friction and heat. Disc brakes are more effective at dissipating heat.

Disc Brake Rotor Rotor Pads Caliper Piston Brake Line Bleeder screw Through Bolts

Rotors

Performance Rotors

Caliper Boot Piston Seal Caliper Housing Bleed Screw O-Ring Bushing Bolts

Caliper*

Disc Brake Pads Asbestos Metallic Semi-Metallic Organic

Wheel Assembly

Disc Brake Assembly

Drum Brakes

Drum Brakes

Drum Brake Action Adjust by driving in reverse and braking

DRUM BRAKES Anchor Pin Wheel Cylinder .Backing Plate Parking Brake Lever Piston Upper Return Spring .Secondary Brake Shoe Primary Brake Shoe Adjuster .Lower Return Spring

Two Types of Drum Brakes

Two Types of Drum Brakes

HYDRAULIC SYSTEM Brake pedal assembly Power booster Master cylinder Proportioning valve Metering valve Warning light valve Lines Calipers Wheel cylinders

Brake Light Hydraulic system fails Parking brake is on

Master Cylinder The master cylinder displaces brake fluid under pressure to brake system. When brake pedal is depressed, push rod moves the primary piston forward in the cylinder. Hydraulic pressure created and the force of the primary piston spring moves the secondary piston forward. forward movement of the pistons causes primary cups to cover bypass holes, hydraulic pressure builds up and is transmitted to the wheel cylinders.

MASTER CYLINDER pedal retracts, the pistons allow fluid from the reservoir to fill the chamber Special sensors within the master cylinder used to monitor level of fluid in reservoir, and alerts driver if pressure imbalance develops. standard dual master cylinder gives front and rear brakes separate hydraulic systems.

Master Cylinder If a brake fluid leak occurs in one system, the other system will still operate, making it possible to. . . STOP THE CAR

Master Cylinder Reservoirs Master Cylinder Vacuum Line To Front Brakes To Rear Brakes Power Booster Brake Pedal

Reservoirs

Reservoir Problems

Gain power from vacuum in intake manifold Power Brake Booster Gain power from vacuum in intake manifold

Booster Operation

Brake Lines Brake lines are steel tubing with copper and lead coatings to prevent rust and corrosion. As the brake pedal is depressed, it moves pistons within the master cylinder and forcing hydraulic brake fluid

Brake Lines Throughout the brake system and into the wheel (or brake) cylinders. The pressure placed upon this fluid causes the cylinder pistons to move, forcing the brake shoes or friction pads and brake drums or rotors to slow the vehicle.

Brake Parts

Hydraulic Valves

Hydraulic Action in the Caliper Squeeze Rotor Push out on Drum

Basics of Hydraulics

Hydraulic Action in the Wheel Cylinder

Braking Videos http://www.raybestos.com/main.htm?techcenter.htm

PARKING BRAKE Parking brake pedal or lever Cables Adjuster Drum brake linkage Disc brake lever

BRAKE INSPECTION Remove all four wheels of the vehicle. On drum brakes remove the drums and wash brake dust with proper cleaner. Check brake pads and brakes shoes for wear. Check drums and rotors for wear and damage.

Brake Fluid Litmus test Color Non compressible Resists boiling High &low temperature stability Non-corrosive to rubber parts Hydroscopic Absorbs water

Brake Fluid DOT 3 DOT4 DOT5 Silicone

Brake Service Visual Inspection Measure Resurface Repair Recondition Bleed Test

Problems

ABS Modulator VSS/ Vehicle speed sensors Electronic Brake Control Unit

ABS Wheel locks up-reduces power to that wheel Pulsates brakes if sliding Pulsates brakes on hard braking Stops vehicle under control NOT faster