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SAE  Acronym for the Society of Automotive Engineers. A professional organization that sets standards for measuring horsepower and torque and for many automotive products such as fasteners, lenses, and lubricants.


[1] A flexible ring, disc or washer that prevents the passage of liquid, air, gas or dirt.

[2] To prevent the passage of liquid, air, gas, etc. by means of a seal or sealant (e.g., on seams, joints, flanges).

[3] to coat a surface (e.g., when undersealing a car) by closing the pores of the anodic oxide layer in order to increase the resistance to staining and its effectiveness against corrosion

Sealant  A liquid or paste used to prevent leakage at a joint. Sometimes used in conjunction with a gasket.

Sealed Beam Lamp  An older headlight design which integrates the reflector, lens and filaments into a hermetically-sealed one-piece unit. When a filament burns out or the lens cracks, the entire unit is simply replaced.

Secondary Winding   An inner winding of the ignition coil; typically 20,000 to 30,000 turns of very fine wire. The opposite is primary winding

secondary winding uses fine wire;
the primary winding is heavy wire

Secondary Wire Secondary Wires

    The high voltage wire from the coil to the distributor tower and from the tower to the spark plugs.

Second Gear  A middle gear which has a faster ratio than low gear, but slower than high gear. It is used for climbing or descending steep hills

Self-Sealing Tires  A tire that is designed to seal a puncture and prevent a slow leak. One popular design seals 90% of tread punctures from nails, bolts or screws up to 3/16 inch in diameter. When a nail punctures such a tire, it's coated with a sealant to prevent slow leaks. When the nail is removed, it automatically pulls additional sealant into the hole in the tire's tread, creating a permanent seal. Also known as nail-guard tires.

Semi Independent Suspension
Semi-Independent Suspension  A rear axle design with a torsionally flexible crossmember, the wheels being located on trailing links

Serpentine Drivebelt

A single, long, wide accessory drivebelt that's used on some newer vehicles to drive all the accessories, instead of a series of smaller, shorter belts. Serpentine drivebelts are usually tensioned by an automatic tensioner.

Shim  Thin spacer, commonly used to adjust the clearance or relative positions between two parts. For example, shims inserted into or under bucket tappets control valve clearances. Clearance is adjusted by changing the thickness of the shim.

Shock Absorber
Shock Absorbers  A term used for what are really dampers. Fittings used to absorb the energy that the wheels convey to the springs. The dampers keep the springs from continuously rebounding. The majority of shock absorbers are hydraulic.

At least one shock absorber is found at each wheel.  

Shock Absorber Struts A strut is a structural piece designed to resist pressure in the direction of its length. On typical "McPherson Strut" use, the shock absorber is built into the strut. Most shock absorber struts are hydraulic units. Like the hydraulic shock struts, faulty units must be replaced as an assembly. Another similar front suspension system is called the "hydraulic shock strut." This strut serves as a shock absorber and replaces the upper control arm. The coil spring, however, is located between the lower control arm and the body structure instead of being mounted directly on the strut.

Shocks  An abbreviation for "shock absorbers."

Side Beam The operating principle of direct-acting hydraulic shock absorbers is in forcing fluid through restricting openings in the valves. This restricted flow serves to slow down and control rapid movement in the car springs as they react to road irregularities. Usually, fluid flow through the pistons is controlled by spring-loaded valves and the hydraulic shock absorber automatically adapts to the severity of the shock. If the axle moves slowly, resistance to the flow of fluid will be light. If it is rapid or violent, the resistance is stronger, since more time is required to force fluid through the openings. By these actions and reactions, the shock absorbers permit a soft ride over small bumps and provide firm control over spring action for cushioning large bumps. The double-acting units must be effective in both directions because spring rebound can be almost as violent as the original action that compressed the shock absorber.

Sleeve Valve  Consists of metal sleeves located between the piston and cylinder wall. When moved up and down, holes in the sleeves coincide with inlet and exhaust parts to provide passage for the gases at the right time.

Slide Hammer  A special puller that screws into or hooks onto a component such as a shaft or bearing; a heavy sliding handle on the shaft bottoms against the end of the shaft to knock the component free.


1. An elecrtomechanical device similar in operation to a relay, however, the movement of the armature or iron core results in changing electrical energy into mechanical energy.

2. An electro-mechanical device used to effect a push-pull mechanical operation using electrical current.

3. A rely with an external mechanical movement. 

An electrically operated magnetic device used to operate some unit. A movable iron core is placed inside a coil of wire which moves because of magnetic attraction when electric current is fed to the coil. When current flows through the coil, the core will attempt to center itself in the coil. In so doing, the core will exert considerable force on anything it is connected to.


clutch solenoid
fast idle solenoid
idle stop solenoid
starter solenoid
stop solenoid
throttle solenoid
vacuum solenoid  

Solenoid Relay  A relay that connects a solenoid to an electrical circuit, such as a starter-motor solenoid relay.

Solenoid Starter Switch  A solenoid-operated starter motor switch

Solenoid Switch  An electrical switch that is opened and closed mechanically by the movement of a solenoid core.

Solenoid Valve  A mechanical valve that is operated by a solenoid to control the flow of a liquid or a gas. Used in braking systems, air conditioning systems, emission control systems, cruise control systems and even suspension and steering systems.

Spark Plug  A device inserted into the combustion chamber of a cylinder on an internal-combustion engine that provides the electrical gap across which the high-tension voltage jumps. This creates a spark that ignites the compressed fuel-air mixture.

Spark Plug Wires The spark plug wire carries 20,000 or more volts from the distributor cap to the spark plug. Spark plug wires are made of various layers of materials. The fiber core, inside the spark plug wire carries the high voltage. Some spark plug wires have a locking connection at the distributor cap. The distributor cap must first be removed and the terminals squeezed together, and then the spark plug wire can be removed from the distributor cap. To work effectively in modern ignition systems, it is important that the resistor ignition cable is capable of producing a specifically designed resistance.

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 A device on the suspension system to cushion and absorb shocks and bumps and to keep the vehicle level on turns. After the stress or pressure exerted by the flexing of the spring has been removed, the spring returns to its original state. The spring does this by first absorbing and then releasing a certain amount of energy. The form of spring may be leaf springs, coil springs, torsion bars, or a combination of these.

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.

Sprocket  A tooth or projection on the periphery of a wheel, shaped to engage with a chain or drivebelt. Commonly used to refer to the sprocket wheel itself.


A small electrical motor that causes the engine crankshaft to begin to turn, which starts the engine running and so starts the vehicle. Invented in 1911 by Cadillac engineers, the manual crank-starter was replaced by an electric motor and thus made it easier and safer for people to start and drive cars.
Also called the "cranking motor."

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.

Starter Circuit The starter circuit is activated when the ignition switch is turned on, thereby opening a second switch in the solenoid, permitting a second flow of electricity from the battery to the starter motor. The engine cranking circuit is made up of a battery, starting motor, ignition switch, and electrical wiring. On placing the ignition switch in the "start" position, the solenoid windings are energized and the resulting shift lever movement causes the drive pinion gear to engage the flywheel ring gear, and cranking takes place. When the engine starts, an overrunning clutch (part of the drive assembly) protects the armature from too much speed until the switch is opened. At this time, a return spring causes the pinion gear to disengage from the flywheel.

Starter Inhibitor Switch  On vehicles with an automatic transmission, a switch that prevents starting if the vehicle is not in Neutral or Park.

Starter Solenoid  A magnetic switch, energize by the ignition switch, that shifts the starter-drive pinion gear into the flywheel ring gear, then closes the electric circuit to the starter.

Starter Solenoid Switch  see solenoid starter switch


 [1] A small hub, upon which a series of vanes are affixed in a radial position, that is so placed that oil leaving the torque converter turbine strikes the stator vanes and is redirected into the pump at an angle conducive to high efficiency. The stator makes torque multiplication possible. Torque multiplication is highest at stall when the engine speed is at its highest and the turbine is standing still.
[2] The stationary windings in an alternator in which electric current is generated; located between drive end and slip-ring end fittings, consisting of a stator frame with windings in three circuits to generate three-phase current which is then rectified by diodes. Also see ROTOR
[3] A self-contained unit of the magnetic pick-up, consisting of a permanent magnet, an inductive winding, and the pick-up core; the stator can be a disc-shaped pole piece with stator tooth or a simple pole piece
[4] The wheel with curved blades (sometimes adjustable) mounted on a one-way clutch in a fluid converter or automatic transmission. It serves as a reaction member, i.e., it multiplies the torque output of the turbine by increasing the momentum of the fluid flow acting on the latter.
[5] The fixed electrical windings on a magneto, alternator, or generator. It turns within the rotor.


Steam Engine   An external combustion engine where water is converted to steam in a boiler outside the cylinder. The steam is then admitted to the cylinder where it expands against a piston. As the steam expands it cools and begins to condense. This mixture of water droplets and steam is forced out of the cylinder on the return stroke and into the condenser where the remaining steam is condensed into water. This water is forced into the boiler by a pump and the cycle is repeated. Steam engines have some notable drawbacks: slow warm up, freezing of the water system in cold weather, and contamination of the water by scale, oil, and sludge which can wreak havoc with the boiler, pumps, and condenser. But they also offer certain advantages: the potential for high fuel economy with low emissions, the ability to start from rest against a load so a clutch is not needed, and the torque developed is greatest at low rpm so in some applications a multiple-ratio gearbox is not necessary.

Read about The History of The Steam Engine
The Automobile here

Steering Arms The steering arms pick up motion from the relay rods and the tie rods, causing the steering knuckles to turn the wheels. They are not used in rack-and-pinion setups.

Steering Systems

The manual steering system incorporates:

1. steering wheel and column,

2. a manual gearbox and pitman arm or a rack and pinion assembly, 

3. linkages; steering knuckles and ball joints; and 

the wheel spindle assemblies. Power steering systems add a hydraulic pump; fluid reservoir; hoses; lines; and either a power assist unit mounted on, or integral with, a power steering gear assembly. There are several different manual steering gears in current use. The "rack and pinion" type is the choice of most manufacturers.

Stroke  The back-and-forth motion of the piston. The length of the motion of the piston from top dead center to bottom dead center.

Strut The main support member in a MacPherson suspension system. The strut also serves as the shock absorber.

Supercharger  An air compressor fitted to an internal combustion engine to force the fuel-air mixture into the cylinders at a pressure greater than that of the atmosphere. Boosts the power of the engine.

Suspension  The assembly of springs, shock absorbers, torsion bars, joints, arms, etc., that cushions the shock of bumps on the road and serves to keep the wheels in constant contact with the road, thereby improving control and traction.

Suspension System 

A system that cushions the passenger compartment of the vehicle from the bumps and shocks caused by the wheels moving over irregular road surfaces. Includes springs, shock absorbers, steering linkage, upper and lower control arms, torsion bars, stabilizers, etc. Sometimes called "springing."

Sway Bar Some cars require stabilizers to steady the chassis against front-end roll and sway on turns. Stabilizers control this centrifugal tendency that forces a rising action on the side toward the inside of the turn. When the car turns and begins to lean over, the sway bar uses the upward force on the outer wheel to lift on the inner wheel, thus keeping the car more level.

Swing Axle  Type of independent rear suspension using half shafts that have universal joints only at their inboard ends on both sides of the differential. This causes a camber angle change of the wheel with up-and-down wheel movements.


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The objective of this Web Page is to familiarize you with basic auto maintenance
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