Drivers-Ed Chapter 28
The gases produced in the internal combustion process must be expelled from the car. Otherwise, the engine may malfunction or carbon monoxide may build up within the vehicle. The exhaust system carries these gases away from the engine. Remember, carbon monoxide can be deadly. A small leak in your exhaust system can lead to a buildup in carbon monoxide, causing you and your passengers to become sick and impairing your ability to drive safely. To prevent carbon monoxide poisoning, have your exhaust system checked routinely.
After fuel is exploded within the engine cylinders, the gases it emits are sent through the exhaust system: The spent gases are released into an exhaust manifold that collects them into a single stream. The catalytic converter reduces the amount of pollutants in the exhaust. The muffler reduces the noise emitted in the combustion process. By law, all cars must have a muffler. The tailpipe vents the hot gases away from the vehicle.
For the rest of the 18th and most of the 19th century, most self-propelled vehicles were powered by steam or electricity. Finally, in 1885, German mechanical engineer Karl Benz designed and built the first practical automobile using the technology still most common today: the internal-combustion engine. On January 29, 1886, Benz received the first patent (DRP No. 37435) for his gas-fueled car.
Another German engineer, Gottlieb Daimler, was also working on a car, with an improved version of the internal-combustion engine, in 1885. By 1894, motor vehicles were common enough that the first Grand Prix race could be held. However, this auspicious event was soon followed by a tragic one: in 1896, the first traffic death occurred when Bridget Driscoll, a mother of two, was killed by a car when she stepped into the street. Upon her death, the coroner stated, "I trust that this sort of nonsense will never happen again."
When new motor oil is poured into your car, it is stored in an oil pan. The oil is sent to the engine by an oil pump. Eventually, it drains back into the oil pan, where it is mixed with the oil in the reservoir and recycled. Over time, engine oil breaks down and loses its protective properties. To ensure your car continues to operate correctly, motor oil should be drained and replaced regularly according to the schedule printed in your owner's manual. Only change the oil yourself if you know what you're doing and can dispose of the old oil safely. In general, its best to have a professional mechanic perform an oil change.
Another engine fluid that you should periodically check and maintain at safe levels is engine coolant, also known as antifreeze. The chemical properties of engine coolant allow it to absorb excess heat in the engine. Coolant also keeps the engine parts from freezing in cold weather. The friction of moving engine parts and the explosion of fuel in the engine cylinders creates more heat than the engine can convert into mechanical power. Extreme temperatures have the potential to cause catastrophic engine failure.
Your brakes are your car's most essential safety feature. If other components stop working, you can still use your brakes to stop your car before something worse happens, but if your brakes fail, it will be more difficult for you to get off the road safely. To help avoid such situations, there are two independent braking systems installed in your car: The service brakes, which are activated by your brake pedal, are used to slow and stop your vehicle while driving. Although typically used to hold your car one place while stopped or parked, the parking brake (also called the emergency brake) can also be used to slow your vehicle in an emergency.
As we discussed in Unit 10, the service brakes work by pushing hydraulic fluid through the brake system, causing the brakes to apply enough pressure to each wheel to slow or stop its spinning. In modern cars, the front wheels are controlled by a different set of brakes than the rear wheels. Because the two systems function independently, the brakes controlling one set of wheels are more likely to continue working even when the other set fails.
However, while automobiles have changed American society in positive ways, they have also caused enduring problems. Cars have led to increased urban sprawl and air and water pollution, and continue to contribute to thousands of traffic deaths in the U.S. each year. Indeed, since 1965, when emissions regulations were introduced and seat belts became mandatory, automobile manufacturers have focused on innovations aimed at reducing the social costs of cars themselves.
Because of the problems associated with automobiles, some have argued that the current levels of car usage cannot be sustained. However, car developers have a vested interest in seeing cars succeed, and have sought to develop ways of minimizing the social and economic impacts of automobiles. These include: Increased fuel efficiency Decreased vehicle emissions Electric and hybrid cars Integrated vehicle systems Safety features to minimize the impacts of collisions
The success of the Ford company and its main competitor, General Motors (which became the world's largest automobile manufacturer) would not have been possible if there had not been concurrent improvements to the nation's roads. In the 1890s, a system of roads began to be built primarily for wagons, coaches, and bicycles. As cars grew in popularity, the U.S. Congress began to pass a series of Federal Aid Road Acts to fund road improvements in the states. By the 1950s, these acts had provided for the creation of a national Highway Transportation System.
By 1930, most of the technologies still used in cars today had been invented, including the electric ignition, multi-valve engines, steering wheels, four-wheel drive, drum brakes, and transmission systems. American manufacturers dominated the automobile industry until the 1970s, when they began to be challenged by the growing sales of Japanese and German cars. Today, while China has become the world's leading producer of automobiles, American manufacturers remain on the cutting edge of automotive innovation.
The United States has been fundamentally transformed by the coming of cars. Many cultural shifts have been made possible by the automobile, including: Increased mobility of the US population Accelerated development of remote areas Major population growth in urban areas and the explosion of suburbs Increased access to goods and services, and to better education and health care The replacement of brick streets with asphalt roads
Cars occupy a special place in the American imagination. Cars have long been linked with status, power, and physical and social freedom. Because of these associations, they have exerted a strong pull on young people since the 1950s. Moreover, the automobile industry has also been a powerful force driving the American economy. Countless people work for automobile manufacturers directly, or for the industry indirectly by developing new technologies, producing individual parts, repairing existing cars, and even producing laws to govern automobile use.
The fuel-air mixture is transported to the intake valves of the engine by means of an intake manifold. The intake manifold pulls the fuel-air mixture from the carburetor or fuel injector and distributes it evenly to each cylinder in the engine. Even fuel distribution helps the engine operate efficiently.
Clean fuel is important to ensuring that your engine functions properly. Carburetors and fuel injectors have many small jets and passages that can become clogged or damaged by impurities in the fuel. To ensure this cleanliness, fuel filters are installed in the fuel line between the fuel tank and the injection system. Moreover, all gasoline sold in the United States is now required to contain certain additives to help prevent deposits from forming in your engine and fuel system.
There are two different types of brakes used in service brake systems: disc brakes and drum brakes. Both types of brakes rely on friction to slow the spinning of the wheels by converting the kinetic energy of the moving vehicle into heat. For a long time, vehicles used drum brakes alone. However, in the 1970s, discs brakes were introduced and soon became standard on the front wheels of all cars, where most of the stopping power is needed. Drum brakes are still used on the rear wheels of most cars, although more and more cars are using disc brakes on the rear wheels as well.
Drum brakes consist of a brake drum that rotates along with the wheel. Inside of each brake drum, there are a set of brake shoes. When the brake pedal is pressed, the brake shoes press against the inside wall of the brake drum, slowing the spinning of the wheel. Drum brakes tend to be less effective in situations that subject the brakes to high stress because the heat created by the action of the brakes tends to be trapped inside the brake drum. Once the brakes are saturated with heat, they become unable to slow the car any further.
During your weekly assessment of your car's condition, you should perform any maintenance checks that don't require looking under the hood. Every week, you should: Check your headlights, taillights, turn signals, and emergency lights, as well as the warning lights on your dashboard. Make sure your emergency kit has all the essentials, including a first-aid kit, a fire extinguisher, basic tools, and water. Test the flashlight in your kit to make sure the batteries are still good. Check the performance of your windshield wipers and your heating, ventilation, and air conditioning (HVAC) system. Make sure your seat belts and latches are working and in good condition.
Every week, you should also check your tire pressure and look for any signs of tire wear or damage. Check each tire for heavy or uneven tread wear, cracks, or debris stuck in the treads. Making sure your tires are properly inflated is one of the easiest things you can do to increase their longevity and improve your car's gas mileage. Keep a tire gauge in your car to check your tire pressure. If your tires need to be inflated, you can usually find an air pump for that purpose at a local gas station if you don't have one of your own.
Your vehicle's fuel system delivers the gasoline and air to the engine that are required for combustion. Gas is stored in the fuel tank, which is usually located near the rear wheels of the vehicle. Fuel is transported from the fuel tank to the engine via a reinforced fuel line that is designed to be relatively resistant to wear.
Gas is drawn from the fuel tank by an attached fuel pump that delivers enough fuel to the engine to keep it working properly. The fuel pump is also responsible for maintaining pressure in the fuel line and making sure that the fuel doesn't evaporate or boil.
Every month or two, take a look under your hood during your weekly maintenance check. While you should leave most under-the-hood tasks to a professional, it's your responsibility to monitor: The level of motor oil on the dipstick Transmission fluid levels Brake fluid levels Coolant levels Windshield washer fluid levels Battery connections The tension and condition of the drive belts The condition of the air and oil filters Consult your owner's manual to find out how to perform these maintenance checks.
Get in the habit of performing these maintenance checks at the same time even though some fluids will only rarely need to be refilled. You're more likely to forget to check something if you have a different schedule for performing each maintenance task. When fluids in your car need to be replenished, you can take your car to a professional or perform the task yourself. If you decide to do the job yourself, be sure you choose a product that will work in your car and follow the procedure recommended in your owner's manual.
The most well-known American manufacturers of steam-driven automobiles were the Stanley brothers of Massachusetts. They produced their Stanley Steamers from 1897 until after World War I. Within a few years, however, American manufacturers would begin to mass produce cars with internal-combustion engines. These men included Henry Ford, who founded the Ford Motor Company in 1903, proclaiming, "I will build a car for the great multitude."
In October 1908, Henry Ford made good on his promise, introducing the Model T at a price of $950. By 1927, the year it was discontinued in favor of other models, the price had reached as low as $280, a single car could be assembled in 93 minutes, and over 15 million Model Ts had been sold in the United States alone. The Model T heralded the beginning of the motor age. By the 1920s, the automobile had evolved from a novelty used mostly by the well-to-do to an essential form of transportation for the ordinary citizen.
As more fuel is supplied to the engine, the crankshaft begins to rotate so rapidly that, if it were connected directly to a car's drive wheels, it would produce speeds too fast to drive safely in most situations. The transmission uses a series of gears to adjust the output speed of the engine so that your wheels will spin at the desired rate while peak engine performance is maintained. In a car with a manual transmission, the higher the gear the driver selects, the less the speed of the wheels will be reduced.
In a vehicle with an automatic transmission, the best gear for traveling at a given speed will be selected automatically. Today's automatic transmissions are highly complicated and contain mechanical, hydraulic, and electrical systems, as well as computer controls. Remember to check your fluid periodically to make sure there are no leaks. If you notice an oily spot under your car that is pinkish in color (transmission fluid is pink or red), have a mechanic check your transmission immediately.
Texas law requires you to prove that your car is in good condition by passing a safety inspection annually. Your tires, brakes, exhaust system, lights, seat belts, and more will be inspected. If you pass the test, you will be issued an inspection sticker that will remain valid for one year. If you fail the inspection the first time, you can have your car reinspected at no additional cost if you return within 15 days with the problems fixed. However, by planning ahead and having your car serviced before your inspection, you can avoid this needless hassle.
In addition to the safety inspection, drivers in many Texas counties are required to have an emissions test performed annually. Gasoline-powered vehicles that are between 2 and 24 years old must receive an emissions test in the following counties: Brazoria, Collin, Dallas, Denton, El Paso, Ellis, Fort Bend, Galveston, Harris, Johnson, Kaufman, Montgomery, Parker, Rockwall, Tarrant, Travis, Williamson. Find out more about safety inspection and emissions test requirements on the Texas DPS website.
Gasoline is the most important fluid in your car. Be sure to choose gasoline appropriate for your car. Generally, you should refill your gas before your tank gets less than a quarter full. Never "top off" your tank when refilling the gas in your car: all you'll do is waste fuel. When you are done refueling, make sure the cap on the gas tank is completely secured.
In order to make sure you remember to perform maintenance tasks, you should develop a fixed routine for checking your car and schedule regular visits with a professional mechanic. It's a good idea to set a specific time each week to check the condition of your car. Don't try to check your car when you're feeling rushed or if you've just finished driving, as its components may be too hot to assess accurately.
Historically, cars have been built around rigid ladder-like frames, usually made out of steel, designed to handle a great amount of stress and keep the car's components in alignment. The body-on-frame approach allows manufacturers to make changes to the bodywork and interior while keeping the chassis unchanged. While frames were found universally in older automobiles, today many cars use lighter and more crash-resistant unibody designs that do not need a frame. Frames are now used mostly in truck and bus construction.
In unibody cars, all the vehicle's components are attached to the body and floorpan that provide the vehicle's structure. Because a heavy frame is unnecessary in these designs, they weigh less and can be built more cheaply. Traditionally, the body of a car was built of steel sections, although modern car bodies often make use of lighter materials, including aluminum, durable plastic, and carbon fiber. These lighter materials make for better fuel efficiency while still ensuring that vehicle occupants remain well protected.
To create the fuel-air mixture used in the internal combustion process, your car draws air from the environment, through the car hood, and into the engine. As with fuel, foreign materials in the air can cause problems if they are allowed to enter the engine. As a result, air filters are installed in the fuel system to separate dust and other particles from the air before it enters the carburetor or fuel injector. Replace your car's air filter at each tune-up to help minimize wear to your engine.
Leaks in your fuel system can cause fires or expose you to toxic gases. These leaks can occur in the fuel tank, fuel lines, and fuel pump, as well as in the carburetor or fuel injector. Leaks can even occur if you fail to securely reattach the cap to the fuel tank after you refill your gas It is extremely dangerous to drive a car with a fuel leak. If you can smell gasoline in the cabin after filling up, you should get out of the car and have a maintenance technician check it for leaks.
It's always preferable to attend to a situation before it becomes a problem. For instance, by regularly changing the oil in your car, you can prevent severe engine damage later on. Any time that a component in your car seems to be acting unusually or a warning light on your instrument panel remains active, you should have a professional check your car. While going to a mechanic may be inconvenient, acting now may allow you to correct a problem before it becomes expensive or dangerous.
Maintaining your car starts by making sure that your car is clean and well-fueled whenever you get on the road. Keep your car clean inside and out. When your car is clean, dirt is less likely to be sucked into the engine compartment and you will be better able to see the road. However, if you wash your own car, don't waste water and be sure you use cleansers that are safe and appropriate for the task.
The procedures performed at your tune-up will be determined by how long it has been since each procedure was last performed. In general, your mechanic will check the following systems every 15,000 miles: The brake system, including brake pads and shoes and the parking brake The cooling system and potential sites of coolant leaks The steering system, especially the gear box The suspension system, including the springs and shock absorbers The air filter
Moreover, your mechanic will typically check the following systems every 30,000 miles: The exhaust system The fuel filter The engine valves The drive belts The automatic transmission system The ignition system, including the spark plugs (unless they are designed to last 60,000 miles or more) The battery
As computer technologies become more advanced, advanced systems are becoming more deeply integrated into modern vehicles. Indeed, some researchers want to eliminate the dangers of human error, distraction, and intoxication by developing cars that can guide themselves. Whatever happens, cars are likely to remain central to American society. For many, they provide safe, efficient, and affordable access to opportunities that would otherwise be out of reach.
Most cars respond immediately to a driver's commands, yet behind these smooth operations are many complex components that have been carefully designed to work together in an efficient and apparently seamless way. While learning how these parts work together may seem challenging, understanding automobile systems will help you appreciate the importance of maintaining every part of your car. Moreover, a solid grasp of how your car works can make you a more confident and conscientious driver.
Before fuel can be delivered to the engine, it must be mixed with air so that it will combust when ignited by the sparkplug. In order to achieve ideal fuel efficiency, the amount of fuel sent into the cylinders of the engine must be precisely controlled. In most older cars, this process is performed by a carburetor. The carburetor is a tube-shaped device that opens up when the accelerator pedal is depressed. As air flows through the carburetor, a vacuum is created that pulls fuel into the air stream and sends this mixture into the engine.
Most modern cars have fuel injectors instead of carburetors. Fuel injection works by atomizing fuel that is received from the fuel pump and forcing it through a tiny nozzle at high pressure. This allows for more precise control over the air/fuel ratio supplied to the engine. Cars with fuel injectors typically have better fuel efficiency, start more reliably, and require less maintenance than those with carburetors.
Changes in noise level, abnormal amounts of fumes, and rattling sounds coming from underneath your car can signal problems with your exhaust system. If your exhaust system seems to be acting erratically, have it checked for leaks and loose connections. In most cases, it is illegal to make modifications to your exhaust system or to install a bypass device to increase the noise level of your vehicle. If you make exhaust modifications, your vehicle may not pass inspection.
Now that you better understand the systems that provide power to your vehicle, it's time to consider the steering system that allows you to control the direction that it moves. The steering system consists of the various components that connect the steering wheel to the front wheels of the car. Together, these components allow you to change where your car is going by pointing the front wheels in the direction that you indicate with the steering wheel.
Most modern vehicles are manufactured with a power steering mechanism. Without power steering, the driver has to exert considerable force to turn the steering wheel. This is especially true in large vehicles, as increased vehicle weight and length make steering more difficult. In vehicles with power steering, a hydraulic piston or electrical motor provides most of the energy needed to move the wheels, allowing any driver to steer the car with relatively little effort.
Pay attention to the condition of your steering system. If your wheels don't respond properly when you steer, or if you have difficulty steering even when your tires are properly inflated, there may be a problem. Steering problems may cause your car to shimmy, wobble, shake, or pull to one side unexpectedly, and to produce squealing sounds when you turn. Not only is it costly to repair a broken steering system, but if the steering wheel stops working while you're driving your car, you may not be able to avoid a collision.
Most vehicle fluids are available in many varieties. Don't mix fluids with different chemical compositions, as they could interact in unpredictable ways and damage your car's components. Even though they may be more expensive, you can save money in the long run by investing in high-quality fluids that will protect your engine better. Keep extra motor oil and vehicle fluids around so that you are prepared if you find that your car is running low.
Perform a more thorough maintenance check twice a year. Every six months you should assess: The air pressure in your spare tire The operations of your parking brake The hinges, latches, locks, and weather strips on your car's doors The drain holes in the body and doors designed to keep moisture from accumulating inside your car.
The grooves in your tires should be at least 2/32 inches thick. You can measure the grooves in your tire with a tread depth gauge or by checking the tire wear bars. For quick reference, you can insert a penny into the groove with Lincoln's face facing you. If you can see all of Lincoln's head while looking at the side of the tire, the treads are too shallow for driving in wet weather and the tire should be replaced.
Properly inflated tires will help you control your car better and maintain good gas mileage. Over-inflated tires are more likely to wear out quickly, while under-inflated tires flex too much and tend to overheat, which can potentially cause a blowout. Keep a reliable tire gauge in your car and check your tire pressure regularly. Cold tires should be inflated to the pressure recommended by your car's manufacturer in the owner's manual. Don't inflate your tires when they are warm, as the pressure will drop as they cool.
Perhaps you've heard the expression, "An ounce of prevention is worth a pound of cure." This statement is especially true of automobiles. Regular maintenance is like preventative health care for your car. By consistently performing low-cost maintenance tasks, you can avoid high-cost repairs and prolong the life of your car's tires, brakes, and other vital systems. Moreover, regular maintenance can prevent vehicle malfunctions and emergency breakdowns that could endanger your life in the future.
The best source of maintenance information about your car is your vehicle owner's manual. A list of maintenance services, including the intervals of mileage or time after which they should be performed, is included in every owner's manual. Your car's manufacturer wants to help you keep it in good condition, but no carmaker can know exactly how every vehicle will be used. Because of this, every owner's manual contains different maintenance schedules for different driving conditions.
If your engine temperature remains abnormally high or seems more erratic than usual, you may have a leak in your radiator or your coolant may need to be replaced. Breakdowns, collisions, and costly repairs can be avoided by keeping your cooling system in good working order. This involves regularly checking under your car for coolant leaks, maintaining the proper amount of coolant, and changing it according to the recommendations of your vehicle's manufacturer.
The electricity needed to power many of the devices in your car, including the lights, dashboard indicators, and computer systems, is produced, stored, and distributed by an elaborate system of circuitry and electrical components. Your vehicle's primary source of electrical power is the battery. The battery supplies the electricity needed to start the engine and used to run auxiliary devices such as vehicle lights and the stereo system when the engine is off.
The engine produces the drive power that propels a vehicle forward or backwards. Today, engines can be found in many configurations, including 4-cylinder, 6-cylinder, and 8-cylinder (V8) engines. The more cylinders there are in an engine, the more power it will have. Each cylinder has its own piston, each of which is connected to a single crankshaft that propels the vehicle.
The engine works by burning fuel in each of the cylinders, which are also known as combustion chambers. This process is known as a four-stroke combustion cycle. In each cylinder: The piston moves down, drawing in a fuel-air mixture. The piston moves up, compressing the fuel-air mixture to make it more explosive. The sparkplug ignites the fuel-air mixture, causing an explosion that pushes the piston down with great force, turning the crankshaft that powers the car. The piston rises, forcing out the burned fuel in the form of exhaust. The piston in each cylinder fires at a different time in accordance with the engine firing order.
Because driving is such a central part of our culture, it may be easy for you to take your car for granted. In fact, the modern car is a sophisticated machine that relies on ingenious technologies innovated over the course of more than a century. Throughout history, people have used various vehicles to transport them from one place to another. However, it was the development of mechanical propulsion technologies in the 1700s and 1800s that allowed inventors to conceive a new mode of transportation that could propel itself: the automobile.
The first self-propelled vehicle was built in Paris in 1769 by the French engineer Nicolas Joseph Cugnot. It was a heavy, three-wheel carriage that was powered by a large boiler attached to the front of the car.
Coolant is primarily stored in the radiator of your car. Coolant flows from the radiator through passages inside the engine. As the coolant lowers the temperature of the engine parts, the coolant itself becomes hotter and expands. Most radiators have a recovery tank that captures the coolant that has expanded and returns it to the radiator. The radiator cools the warm coolant with radiator fans, as well as by air currents when the vehicle is in motion.
The flow of coolant is controlled by the thermostat, a heat-sensing valve which allows the engine to quickly heat up to the proper temperature. The thermostat also determines whether coolant should be pumped back into the engine directly or should be sent to the radiator first to be cooled. Remember to monitor your engine temperature by checking the temperature gauge as you drive. If your engine overheats suddenly, there may be a problem in your car's cooling system.
The timing belt coordinates the operation of the valves that allow fuel into and exhaust out of the engine cylinders. The timing belt connects the crankshaft to the camshaft, which is responsible for opening and closing each valve at the proper time. The timing belt is subject to consistent wear over time. Generally, a timing belt becomes unreliable after 60,000 miles and should be replaced. If the timing belt breaks while you're driving, your engine may be permanently damaged.
The rate at which the crankshaft in the engine is spinning is displayed on your vehicle's tachometer. In most modern cars, the engine performs best when it is rotating at 5,000 to 6,000 revolutions per minute (rpm). This is equivalent to 100 revolutions every second! Remember, if the needle on your tachometer is pointing to the red area, your engine is moving too fast. Reduce the pressure on your accelerator pedal before your engine explodes!
The steering wheel is connected to a steering column that extends down to the front axle of the car. The ignition switch and control levers, among other devices, are typically mounted on the part of the steering column that extends into the cab of the car. In older cars, the steering column was a rigid metal bar that had the potential to impale the driver in the event of a serious collision. To minimize this risk, most modern steering columns are designed to collapse on impact.
The steering column is connected to the front wheel axle through the steering gear box. The gear box converts the rotary movement of the steering wheel into the lateral movement necessary to point the front wheels in the desired direction. For instance, when you turn the steering wheel to the right, the gear box will cause the steering mechanism on the front axle to shift towards the left. As it does so, it will pull the back of the right wheel inward and push the back of the left wheel outward according to how far you have turned the steering wheel. If you turn the wheel too far, you could jam the steering mechanism.
When you press down on the brake pedal in a car with ABS, you may feel it vibrating or hear a grinding noise. This is an indication that the system is working properly: to prevent your wheels from locking up, the ABS system will pulse the brake up to 15 times a second. Pay attention to your ABS system when you start your car to make sure it is working properly. When you turn on your car, the antilock braking system will check itself. While this test is conducted, the ABS indicator on the dashboard will be lit and you may hear a brief motor or clicking noise. If your ABS is working properly, the warning light will go out when the test is complete.
Tires are rubber coverings that are placed on the wheels of your vehicle. They have two basic functions: absorbing shocks by flexing over the contours of the road, and providing traction so that drivers can accelerate, brake, and steer. Every tire has a distinctive tread. These treads are designed to provide traction and wear away slowly. The grooves in tires are intended to channel water so the tire will have better contact with the surface of the road.
Like drum brakes, disc brakes are attached to the wheels and rotate along with them. However, instead of containing the brake components within a drum, disc brakes consist of a spinning rotor and a small caliper that is lined with brake pads. When the brake pedal is pressed, the caliper clamps the rotor between the pads, slowing the spinning of the rotor and the wheel. Because the rotor of the disc brake is exposed to air rather than contained within a drum, the heat of the braking process is allowed to dissipate, making overheating much less likely.
To make sure that your hydraulic braking system works when you need it to, your brakes should be inspected and maintained according to the manufacturer's specifications: The most common type of service required for drum brakes is shoe replacement. Some drum brakes have an inspection hole on the back so you can see how much material is left on the shoe. The most common type of service required for disc brakes is pad replacement. When the friction material on the brake pads has been worn away, a wear indicator becomes exposed that causes a squealing sound when it contacts the brake rotor. If you hear this squeal, you need new brake pads. Consult your owner's manual to learn how to take care of your brakes, especially if you aren't sure what kind of brakes you have.
Service brakes use a hydraulic system that requires brake fluid to transmit force to the brakes. Because brake fluid does not compress under pressure, it can be pushed through the brake lines to activate the brakes when you press the brake pedal. Brake fluid is usually stored in a reservoir in the engine compartment. Brake fluid levels should be checked periodically. You should refill the reservoir whenever the fluid levels run low. If you run out of hydraulic fluid, your brakes won't respond when you try to stop your car.
Unlike the service brake system, the parking brake relies on a cable rather than hydraulic fluid. When the parking brake is engaged, a steel cable attached to the rear wheel brakes is pulled tight, activating the brake shoes or brake pads. When the parking brake is released, the cable slackens and the brakes disengage. When service brakes fail, it is often because the roadway is not generating enough friction and the pressure of the brake fluid drops, causing the wheels to lock. In these situations, the parking brake can be used as an emergency brake.
Every tire is assigned grades according to the Uniform Tire Quality Grading system (UTQG) to help consumers make better choices. These ratings are indicated on the tire's sidewall. Treadwear ratings indicate how long a tire is expected to last. Tires are rated against a control tire assigned a grade of 100. A tire graded 200 should last twice as long as a tire graded 100. Traction ratings indicate how well a car can brake on wet roads. Tires can have a traction rating of AA, A, B, and C, with AA being the best and C the worst. Temperature ratings indicate how well a tire can endure extreme heat. Tires can have a temperature rating of A, B, and C. Tires rated "C" should not be used on very hot roads. The NHTSA has provided more information on tire ratings here.
When changing your tires, consult your owner's manual and ask for professional guidance to ensure that you choose the tires most suited for the kind of driving that you do. Use the information printed on the tire sidewall to help you find a tire that meets the manufacturer recommendations for your car. You should replace your tires when they become worn or cracked or when the tread depth is low. Generally, it's best to replace tires in sets of four.
Your car's frame, body, engine, and transmission are suspended above the wheels by a system of springs known as the suspension system. The suspension system keeps the vehicle stable and allows the wheels to maintain contact with the road while rising and falling independently of the rest of the car. Your suspension system may need to be checked if your car does not appear to be level when it is parked or bounces more than usual when you drive. Uneven tire wear can also be a sign of suspension problems.
When you drive over a road, irregularities like debris and potholes can jar the car up and down, causing the wheels to lose contact with the road and come slamming down. Springs in the suspension system absorb this up-and-down movement so the wheels can follow the road without affecting the whole body of the car. However, springs alone would cause the car to bounce and sway every time they absorbed the energy of a bump. In order to improve the comfort of people in the car, shock absorbers are installed to reduce this effect.
When you turn your key in the ignition switch, the battery sends energy to activate the starter motor. The starter motor sets the engine in motion and activates a sparkplug to ignite fuel in the combustion chambers, bringing the vehicle to life. In cars that rely on a traditional internal combustion system, the engine does not need additional electricity once it has been set in motion. However, starting your car requires more electricity than any other task.
When your car is running, the electrical power is provided by the alternator rather than the battery. The alternator converts some of the mechanical energy produced by the engine into electricity that is then distributed throughout the vehicle. Some of the electricity the alternator produces is used to recharge the battery. This is why a car can generally run so long on a single battery and why the battery is most likely to be drained when you leave electrical components (such as vehicle lights) on when your engine isn't running.
You should also replace tires that have been on your wheels for more than six years, even if they do not seem worn, and always buy tires new. The quality and safety of tires decrease with time, even if they are never used on a car. Sometimes, there is no visual indication that tires are ageing (their tread may look fine), but chemical reactions within the rubber can make tires unsafe. At high speeds, the treads of old tires can separate and cause a deadly collision.
You can prolong the life of your tires by rotating them regularly. Refer to your owner's manual for the recommended rotation interval and pattern for your car. The rotation pattern varies from car to car, but an interval of 6,000 miles is generally recommended. Tire rotation also gives you the opportunity to make sure your tires and wheels are balanced. Normal wear and road conditions can throw off a car's alignment. At least once a year, you should have a qualified technician check your car's alignment and inspect the condition of your tires.
In a car with a standard brake system, when you slam on the brakes, you can lock the wheels before your car's kinetic energy has been absorbed, causing a skid. In this situation, you must release the brake pedal (to unlock the wheels) and pump the brakes rapidly (to restore pressure to the hydraulic fluid). To prevent this problem, most modern vehicles use an Antilock Braking System (ABS) to help keep your brakes from locking. In cars equipped with ABS, the system will automatically pump the brakes when you firmly press down on the brake pedal. If you have ABS, you should never pump the brakes yourself.
Your car's antilock braking system can detect when a wheel is about to lock up and activate valves to reduce pressure on the brakes before the wheel stops spinning completely. When the wheel begins to pick up speed again, pressure is reapplied. This process is repeated continually as long as you keep your foot on the brake pedal. ABS also improves your ability to perform evasive maneuvers because it allows traction to be maintained when you brake suddenly. This allows you to guide your car to a safe road position while reducing your speed.
Electricity is generated when a rotor attached to the alternator is spun rapidly by a belt connected to the crankshaft of the engine. In older cars, this connection is provided by a devoted alternator belt, but most modern cars use a serpentine belt that drives multiple devices, including the air and water pumps and the air conditioning system, at the same time. Your car's alternator or serpentine belt must be in good condition for these systems to run. If the belt snaps while you are driving, all devices powered by the belt will stop working.
Your electrical system must be properly maintained. Without electricity, none of vehicle devices controlled by a computer, including power steering, antilock brakes, and stability controls, will work. Moreover, if you get into a collision, your air bag will fail to deploy and you won't even be able to open your electric windows or door locks. The alternator or serpentine belt must be replaced if cracked, soaked or glazed in oil, badly worn, or otherwise damaged. The tension of the belt should be adjusted in accordance with the vehicle manufacturer's guidelines. Keep the battery connections clean, particularly around the area where the cables connect to the positive and negative poles. Fall is generally considered the best time of year to have battery terminals checked.
Not every maintenance task that should be performed on your car is something you can do yourself. You should regularly have service procedures performed on components that are likely to wear out quickly or fail suddenly, such as: A professional oil change Oil filter replacement Tire rotation In the past, it was recommended that cars should be serviced by a trained mechanic at least twice a year, or every 3,000 to 5,000 miles, but many modern cars can go longer without service. Consult your owner's manual to find out when you should take your car to a mechanic.
Your owner's manual will also tell you when to have a comprehensive tune-up performed. In general, tune-ups should be performed every year or so, though the amount of time between tune-ups can vary significantly for modern cars due to advances in vehicle technology. For instance, drivers used to be encouraged to get annual tune-ups was because spark plugs needed to be replaced frequently. However, cars manufactured today typically need their spark plugs replaced only once every 100,000 miles.