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Seat Belts and Air Bags |
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Air bags protected occupants in ways that seat belts alone cannot. The air bag
spreads out the violent impact of a crash and kept occupants from smashing
against the steering wheel, dashboard or windshield. Having an air bag and
wearing an effective seat belt is the best protection. By this, you are
protected from frontal crashes by the air bag -- you are also protected by the
seat belt in all other types of crashes. With an "effective" safety belt, your
body will stop, in a crash, before you hit or go through the windshield and
parts of your car. Seat belts are especially important in small cars, because
your chances of being killed or badly hurt in a collision with a big car is
eight times greater. Wearing your belt will greatly improve your chances of
survival. Air bags can reduce the risk of death in a head-on collision by 26%%
and in all serious accidents by 13%.
Air bags are only useful in frontal crashes, so it is not a good idea to skip
your seat belt because you have an air bag. Air bags provide very effective
protection in frontal crashes, inflating instantly to protect the driver or
passenger that has an air bag. They spread the impact of the crash over the
individual's head and chest and protect fragile body parts from the car's hard
surfaces. Many basic improvements have been introduced into cars in recent
years. These include anti-burst door latches, safety glass, energy-absorbing
steering wheels and columns, head restraints and various seat belt systems. The
benefits of the three-point seat belts have been firmly established: over 50%%
of fatal and serious injuries to car occupants would be avoided if all
occupants wore their seat belts.
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Seats |
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There are basically two types of seats; bench seats or bucket seats. A bucket
seat is a low, separate seat for one person. Although we think of them as
relatively new, it is interesting to note that in 1905 Henry Ford's first model
had bucket seats. Bench seats are a continuous cushion and backrest across the
width of the car (although some vans might have them running along the length
of the van). Bucket seats are single units with a separation between the left
and right seats. Usually vinyl leather and fabric are used for upholstery.
"Flatsprings" are used for comfort, which are pieces of wire bent into a zigzag
pattern. Both ends of the wire are attached to the seat frame, with additional
lengths added every six inches. Foam padding is used to cover the flatsprings.
The front seats ride on rails that are bolted to the floor. This arrangement
allows the seats to move backwards and forwards to suit the driver or
passenger. The seat adjustment lever is attached to a latch that fits into
teeth along the rail. Moving the lever releases the seat, and allows the seat
to move. At any point of the seat's movement, releasing the lever engages the
latch with one of the teeth. Usually there is also a pull-spring; this draws
the seat forward when the latch is released. The rear seat usually doesn't
move, because it is secured to the floor of the car. It's backrest is attached
to the partition between the passenger compartment and trunk. |
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Secondary Brake Shoe |
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The Secondary brake shoe is the shoe in a set that is energized by the primary
shoe. A brake shoe is a carrier to which the brake lining is attached, used to
force the lining in contact with the brake drum or rotor. When brakes are
applied, the brake shoes or friction pads are forced into contact with the
brake drums or rotors to slow the rotation of the wheels. The vehicle slows
down as a result of the friction between the tires and the road surface. |
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Thrust Bearings |
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Thrust bearings are similar to ball bearings except that the plates that the
balls ride between are designed as flat washers. The balls riding between these
washers reduce side-to-side load. These are used inside of the transmission,
rear end and many other areas of the car. |
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Tie Rod Ends |
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Tie rod ends are utilized in the steering linkage, steering knuckle pivot
supports, and various other hinge mechanisms. Ball joints that join the key
parts of the steering linkage pass on the steering wheel's motion no matter
what the angle of the linkage or the vibration from the road. |
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Timing Chain/ Belt |
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The automobile engine uses a metal timing chain, or a flexible toothed timing
belt to rotate the camshaft. The timing chain/belt is driven by the crankshaft.
The timing chain, or timing belt is used to "time" the opening and closing of
the valves. The camshaft rotates once for every two rotations of the
crankshaft. |
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Torsion Bars |
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Torsion bar suspension uses the flexibility of a steel bar or tube, twisting
lengthwise to provide spring action. Two rods of spring steel are used in this
type of suspension. One end of the bar is fixed solidly to a part of the frame
behind the wheel; the other is attached to the lower control arm. As the arm
rises and falls with wheel movement, the bar twists and absorbs more of the
road shocks before they can reach the body of the car. Just like a spring that
rebounds after it has been compressed, the bar untwists when the pressure is
released. Adjusting the torsion bars controls the height of the front end of
the vehicle. The adjusting bolts are located at the torsion bar anchors in the
front cross member. The inner ends of the lower control arms are bolted to the
cross member and pivot through a bushing. |
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Transmission Fluid Dip Stick |
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The transmission fluid dip stick is a long metal rod that goes into the
transmission. It serves check how much transmission fluid is in the
transmission. The dip stick is held in a tube; the end of the tube extends into
the transmission. It has measurement markings on it. If you pull it out, you
can see whether you have enough transmission fluid, or whether you need more by
the level of fluid on the markings. Most manual transmissions do not have
dipsticks, instead they use a filler hole which is at the same level as the
correct oil level. When the oil is topped up or refilled, the mechanic simply
adds oil until the filler hole's level is reached. |
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Transmission Gears |
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Most cars have from three to five forward gears, and one reverse gear. The
transmission changes the ratio of the engine speed and the wheels by connecting
gears in various combinations. First gear connects the engine power to the
drive wheels via a pair of reduction gear sets, which gives increased power and
reduced wheelspeed when the car is beginning to move. Gears work exactly like
levers. A small gear driving a larger one gives an increase in torque, and a
decrease in speed, and vise-versa. Transmission gears are heat-treated, high
quality steel. They have smooth, hard teeth, cut on precision machinery while
red hot. There are many types of gear teeth, but most transmissions use spur
and helical gears. Most of the gears are the helical type, because they last
longer and are more quiet than spur gears. There has to be enough room (a few
thousandths of an inch) between the gear teeth for lubrication, expansion, and
any irregularities in size. |
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Transmission tunnel |
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The transmission tunnel is a cone-shaped formation in the front of the floor
pan. Its shape duplicates the transmission, but it is a little bit bigger and
provides about two inches of clearance around the transmission. The
transmission tunnel does not exist in front wheel drive cars, because the
transmission is on the side of the engine completely under the hood. Only
rear-wheel drive cars have transmission tunnels. A manual transmission tunnel
has a hole in it to allow the shift linkage to be worked from inside the car.
The shifter linkage goes through the transmission tunnel. A rubber boot on the
shifter linkage stops dirt, dust and exhaust fumes from entering the passenger
compartment. The rubber boot is mounted onto the transmission tunnel and
fastened securely around the gearshift linkage. Vehicles with automatic
transmission do not need a transmission tunnel because the shift linkage does
not usually go through the transmission tunnel. The shift linkage in automatic
transmission usually goes in front of the firewall from the base of the
steering column. |
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Tyres |
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A tyre is a tubular corded carcass covered with rubber or synthetic rubber,
which is mounted on a wheel and inflated to provide traction for moving a
vehicle and for assisting the brakes in stopping it. |
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