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► Braking systems evolved from scrub brakes to band brakes to the drum and disc brakes that are used today.
► Electronic brake systems use computer technology to assist with braking by determining speed and needed force to stop.
► The development of electronic brake systems has led to improvements in consumer safety and fuel economy.
► Brake-by-wire systems use computer technology in place of the mechanical or hydraulic connection between the brake pedal and wheel brake units.
► Regenerative brake systems (used in hybrid vehicles) convert a vehicle’s energy into electrical energy, which is stored in the battery for later use.
► Factors affecting the effectiveness of braking systems include road surface, road conditions, vehicle weight and height, load on wheels, type of tire, and aggressive vs. defensive driving.
► Every vehicle has two brake systems: service brake (for stopping the vehicle in motion) and parking brake (for holding the vehicle when stationary).
► Hydraulically operated braking systems use a system of cylinders to transfer pressure from the brake pedal to the wheel.
► The braking system converts a vehicle’s kinetic energy (the energy of an object in motion) into an alternate form of energy (e.g., heat).
► Acceleration and deceleration determine whether the vehicle’s speed is increasing or decreasing. Both require an outside force for action, such as the vehicle’s engine (acceleration) or braking system (deceleration).
► The law of conservation of energy requires that energy must be transformed from one form to another; it cannot be created or destroyed.
► Standard brakes use friction to create resistance, thus transforming kinetic energy into heat energy.
► The amount of force pushing two surfaces together compared to the amount of resistive force generated between the two surfaces sliding against each other is called the coefficient of friction.
► Heat energy created by the braking process gets dissipated into the atmosphere.
► Reduction in a vehicle’s stopping power (brake fade) can be caused by heat fade, water fade, or hydraulic fade.
► Braking systems create rotational force on the vehicle’s suspension, resulting in weight transfer to the front wheels.
► There are three types of levers: lever of the first order (fulcrum in the middle), lever of the second order (load in the middle), and lever of the third order (effort in the middle).
► Engine braking allows the engine to act as a brake by absorbing energy during deceleration.
► Technicians can be held liable for improperly repaired brakes.
► Disc brakes and drum brakes are two types of friction brakes that are used on lighter vehicles; both can be equipped with antilock braking systems.
► Air-operated braking systems, used on heavier vehicles, use air pressure to apply the brakes (drum or disc style).
► An exhaust brake may be used in addition to friction brakes in heavy vehicles and creates engine pressure by restricting the exhaust flow.
► Jake brakes are used in heavier diesel vehicles and rely on compression to slow the crankshaft and increase braking effectiveness.
► Trailers over a certain weight often use an electric braking system to give the driver braking control.
► Parking brake styles include: top hat parking brake, drum-style parking brake, and transmission-mounted parking brake.
► Parking brakes use a ratcheting mechanism to maintain tension on the parking brake cables and assembly when applied.
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