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AUTOMOTIVE BRAKING SYAUTOMOTIVE BRAKING SYSTEMSSTEMS

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How it WorksHow it Works

Friction develops heat which absorbs kinetic energy of the

car

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PURPOSE OF BRAKING PURPOSE OF BRAKING SYSTEMSYSTEM

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.

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Factors Effecting Braking*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

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Types of Braking SystemsTypes 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.

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BASIC PARTSBASIC PARTS

Pedal assembly Hydraulic system Power booster Disc brake assembly Drum brake

assembly Parking brake

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DISC BRAKESDISC 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.

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Disc Brake RotorDisc Brake Rotor RotorRotor

PadsPadsCaliperCaliperPistonPistonBrake Brake LineLineBleeder Bleeder screwscrewThrough Through BoltsBolts

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RotorsRotors

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Performance RotorsPerformance Rotors

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CaliperCaliper Boot Piston Seal Caliper

Housing Bleed Screw O-Ring Bushing Bolts

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Caliper*Caliper*

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Disc Brake PadsDisc Brake Pads

Asbestos Metallic Semi-Metallic Organic

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Wheel AssemblyWheel Assembly

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Disc Brake AssemblyDisc Brake Assembly

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Drum BrakesDrum Brakes

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Drum BrakesDrum Brakes

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Drum Brake ActionDrum Brake ActionAdjust by driving in reverse and brakingAdjust by driving in reverse and braking

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DRUM BRAKESDRUM BRAKES Wheel Cylinder

.Backing Plate

.Secondary Brake Shoe

Upper Return Spring

Parking Brake Lever

Primary Brake Shoe

Piston

Adjuster

Anchor Pin

.Lower Return Spring

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Two Types of Drum BrakesTwo Types of Drum Brakes

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Two Types of Drum BrakesTwo Types of Drum Brakes

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HYDRAULIC SYSTEMHYDRAULIC SYSTEM

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

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Brake LightBrake Light Hydraulic system

fails Parking brake is on

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Master CylinderMaster 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.

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MASTER CYLINDERMASTER 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.

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Master CylinderMaster CylinderIf a brake fluid leak occurs in one system,

the other system will still operate, making it possible to. . .

STOP THE CAR

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Master CylinderMaster Cylinder

ToFront Brakes

To Rear Brakes

Master Cylinder

Reservoirs

PowerBooster

Vacuum Line

Brake Pedal

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ReservoirsReservoirs

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Reservoir ProblemsReservoir Problems

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Power Brake BoosterPower Brake BoosterGain power from vacuum in intake manifold

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Booster Booster OperationOperation

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Brake LinesBrake 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

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Brake LinesBrake 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.

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Brake PartsBrake Parts

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Hydraulic ValvesHydraulic Valves

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Hydraulic Action in the CaliperHydraulic Action in the Caliper Squeeze Rotor Push out on Drum

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Basics of HydraulicsBasics of Hydraulics

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Hydraulic Action in the Wheel Hydraulic Action in the Wheel CylinderCylinder

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Braking VideosBraking Videos

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

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PARKING BRAKEPARKING BRAKE

Parking brake pedal or lever

Cables Adjuster Drum brake linkage Disc brake lever

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BRAKE INSPECTIONBRAKE 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.

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Brake FluidBrake Fluid Litmus test Color Non compressible Resists boiling High &low

temperature stability Non-corrosive to

rubber parts Hydroscopic

– Absorbs water

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Brake FluidBrake Fluid

DOT 3DOT4DOT5

– Silicone

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Brake ServiceBrake Service

Visual Inspection Measure Resurface Repair Recondition Bleed Test

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ProblemsProblems

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ABSABS

Modulator VSS/ Vehicle

speed sensors

Electronic Brake Control Unit

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ABSABSWheel locks up-

reduces power to that wheel

Pulsates brakes if sliding

Pulsates brakes on hard braking

Stops vehicle under control

NOT faster