Speedometer Cable

The speedometer cable is connected either to the gearbox output shaft, transmission shaft, or differential. Speed and record mileage is measured by the rotation of these shafts. This information is sent back through the cable where it is recorded on the speedometer. The speedometer and odometer are driven by a cable housed in a flexible casing, which is connected to a gear in the transmission. Speedometer cables break as the result of age, lack of lubrication, or because the cable casing has sharp bends. It may also break from too much friction in the speedometer head.

Speedometer and Odometer

The analog speedometer that is used on cars indicates its speed and records the distance the car has traveled. A speedometer is driven by a flexible cable connected to the speedometer pinion in the transmission. Speedometers are calibrated in miles per hour and/or in kilometers. The instrument records the distance traveled in miles or kilometers. That portion of the instrument is known as the odometer. Most odometers record the total distance traveled. Some also record the distance of individual trips.

Spoiler

A spoiler is a kind of wing that is mounted on the rear of the car in a horizontal position. Its function is to provide high-speed stability. In most cars, the spoiler is purely cosmetic, as a car has to be going over 100 mph to take advantage of the aerodynamics of the spoiler. Some mini-vans also make use of a spoiler, but it's upside down, and angled. This type of a rear spoiler only keeps the rain off the rear window.

Springs

There are two kinds of springs, leaf springs and coil springs. Springs have life spans that are determined by the number of cycles they can withstand over a certain period of time. If a spring breaks while a car is being driven, the car will suddenly lurch downward. The bottom of the car might be damaged, or you might lose your muffler! Leaf springs are made of individual springs, or plates. If you break one plate of your leaf spring, it won't be noticeable, but your car might begin to lean to one side or the other. Coil springs, if they break, will suddenly drop the front or rear end of your car and impair driving under the normal conditions of full suspension travel.

Starter

The starter converts electricity to mechanical energy in two stages. Turning on the ignition switch releases a small amount of power from the battery to the solenoid above the starter. This creates a magnetic field that pulls the solenoid plunger forward, forcing the attached shift yoke to move the starter drive so that its pinion gear meshes with the engine's crankshaft flywheel. When the plunger completes its travels, it strikes a contact that permits a greater amount of current to flow from the battery to the starter motor. The motor then spins the drive and turns the meshed gears to provide power to the crankshaft, which prepares each cylinder for ignition. After the engine starts, the ignition key is released to break the starting circuit. The solenoid's magnetic field collapses and the return spring pulls the plunger back, automatically shutting off the starter motor and disengaging the starter drive. When the starter is not in use, the drive unit is retracted so that its pinion is disengaged from the flywheel. As soon as the starter is activated, the forward movement of the solenoid plunger causes the shift yoke to move the drive in the opposite direction and engage the pinion and flywheel. The pinion is locked to its shaft by a clutch that unlocks if the engine starts up and the flywheel begins turning the pinion faster than its normal speed. By allowing the pinion to spin freely for a moment, the clutch protects the motor from damage until the drive is retracted.

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