Auto & Shop Information · Practice test 6

Correct answer: the driver's pedal force into hydraulic pressure for the brake lines

A piston inside the master cylinder pressurizes brake fluid when the pedal is pressed, and that pressure travels through the lines to actuate the brakes at each wheel.

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Correct answer: the ABS control module, which modulates brake pressure at each wheel

Each sensor reports its wheel's rotational speed to the ABS module, which rapidly pulses hydraulic pressure at any wheel it detects is about to lock up.

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Correct answer: coating it with a layer of zinc

Zinc both seals the steel from moisture and corrodes in its place if the coating is scratched, which is why galvanised nails and roofing last outdoors. Heating and quenching is hardening, a change to the steel itself rather than a coating.

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Correct answer: oil pump

Driven off the crankshaft or camshaft, the oil pump draws oil from the pan and forces it through galleries to bearings, the valve train, and other moving parts.

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Correct answer: removes particles from the circulating oil

Oil picks up metal particles and combustion soot as it circulates, and the filter traps them before they can score bearing surfaces. It is replaced with every oil change for that reason.

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Correct answer: exhaust gases leaving the engine

Exhaust flow spins a turbine that drives a compressor forcing more air into the engine. That is the difference from a supercharger, which is belt driven off the crankshaft and so costs the engine some power to run.

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Correct answer: the rotor

The calliper squeezes a pad against each face of the spinning rotor, and friction turns the car's motion into heat. Drum brakes use shoes pushing outward instead.

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Correct answer: how coarse or fine its teeth are

Cut grades a file from bastard, the coarsest in common use, through second cut to smooth. Cross-section shape is described separately as flat, half-round, round, or triangular.

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Correct answer: reduces the noise of the exhaust

Internal chambers and perforated tubes cancel and absorb the pressure pulses that would otherwise be heard as a loud bark. Cleaning the gas chemically is the catalytic converter's job.

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Correct answer: old or low transmission fluid

Degraded or low fluid loses its ability to properly engage clutch packs and cool the transmission, leading to rough shifts and the telltale burnt odor.

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Correct answer: a nail driven too close to the end grain

Near the end, there is little wood fiber left to resist the wedging action of the nail, so the fibers split apart along the grain instead of the nail simply seating.

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Correct answer: serpentine (or accessory drive) belt

A single long serpentine belt commonly winds around several pulleys, using engine rotation to spin the alternator, power steering pump, and AC compressor at once.

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Correct answer: stores rotational energy and smooths out the power pulses

Only one stroke in four delivers power, so without a heavy flywheel the crankshaft would surge and stall between firings. Its rim also carries the ring gear the starter engages.

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Correct answer: smooth a surface before finishing

The pad moves in small circles so the scratch pattern does not follow the grain, which leaves a surface ready for paint or varnish. Cutting a groove is a router's work.

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Correct answer: reduces the harmful gases leaving the tailpipe

The converter uses precious metal catalysts to turn carbon monoxide and unburned fuel into less harmful gases. Quietening the exhaust is the muffler's job.

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Correct answer: grind the gears as they fail to mesh smoothly

Without disengaging the clutch, the gearbox's gears are still spinning under load and cannot slide into mesh cleanly, producing the classic grinding sound.

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Correct answer: burning too much fuel for the air available

Black smoke is unburned fuel, so the mixture is too rich, often from a blocked air filter or a leaking injector. Blue smoke means burning oil and white smoke means burning coolant, which is how the three are told apart.

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Correct answer: cutting a step-shaped recess along the edge of one board so another piece fits into it

The rabbet is an L-shaped notch cut along an edge or end, into which a second board's edge fits, commonly seen at the back corners of cabinets and drawers.

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Correct answer: how much current it can deliver to start a cold engine

Cold cranking amps measures the current a battery can sustain for 30 seconds at low temperature, which is exactly the demand a starter places on it in cold weather.

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Correct answer: an internal leak past a caliper or wheel cylinder seal

A worn seal inside a caliper or wheel cylinder can let fluid leak internally past the piston without ever reaching the ground, quietly lowering the reservoir level over time.

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Correct answer: steering system

A pinion gear on the steering column runs along a toothed bar, the rack, converting the wheel's rotation into side-to-side movement of the tie rods. It is the standard arrangement on modern cars.

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Correct answer: remove contaminants from the oil before it circulates through the engine

As oil picks up combustion byproducts and worn metal particles, the filter traps them so cleaner oil keeps circulating and protecting bearing surfaces.

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Correct answer: a brake

A brake clamps the sheet along a line and folds it over a straight edge to a set angle. A shear cuts sheet, a punch makes holes, and a lathe turns round work.

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Correct answer: wear eye protection

A grinder throws hot sparks and metal fragments straight toward the face. Loose gloves are actively dangerous near rotating machinery because they can be caught and pull the hand in, and the tool rest is a guard that should stay fitted and correctly spaced.

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Correct answer: the crankshaft where it rides in the block

Main bearings are the shells fitted in the block that the crankshaft's main journals spin in, carrying the crankshaft's weight and the loads from combustion.

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