ABS SWITCH- Sensor that monitors hydraulic system pressure and controls the pump motor in an ABS application.

AC- Alternating current.
AC GENERATOR- A device that produces alternating current; an alternator.

ACTUATOR- A device that performs an action or outputs a signal in response to a signal from a computer.

AIR BRAKES- Vehicle brakes actuated by air pressure.

AIR COMPRESSOR -A pump that forces air, under pressure, into a storage tank.

ALTERNATOR- An ac generator.
ALTERNATOR BEARING- Needle-or ball-type bearings used to provide a low friction surface for a rotor.

AMMETER- An electric meter that measures current, in amperes, in an electric circuit.

AMPERE- A unit of electric current flow measurement.

ANTI-LOCK BRAKE COMPUTER- ECM that accepts wheels sensor inputs and controls braking of the vehicle.

ANTI-LOCK BRAKES- Computer controlled brakes that will not "lock" and permit the wheels to skid.

ANTI-RATTLE CLIPS- Metal components designed to keep brake pads from vibrating and rattling.

ANTI-SKID SYSTEM- Another name for anti-lock braking system.

ARMATURE- Rotating support for multiple windings in a motor.

ASPECT RATIO- The relationship of tire height to width or profile.

AUTOMATIC TRANSMISSION- A transmission that does not have to be shifted manually.

AUTOMATIC TRANSMISSION FLUID- Oil with special additives to make it compatible with friction clutches and bands.

AUTOMOTIVE CLUTCH- A mechanical device used to connect and disconnect a manual transmission from engine power.

AXLE- A cross support on a vehicle on which supporting wheel, or wheels, turn( s).

AXLE END PLAY- In-and-out movement of the axle, adjusted to specification by using shims.

AXLE SHAFT RETAINER- Devices that attach to the outside of an axle housing to prevent the axles from sliding out.

AXLE SHIMS- Used between the axle housing and retainer to limit end play of the axle.

BACKLASH -The backward rotation of a driven gear that is permitted by clearance between meshing teeth of two gears.

BACKING PLATE- A component that holds the shoes, wheel cylinder, and other parts inside a brake drum.

BACKUP LIGHT SWITCH- An electrical switch that completes a circuit to the backup lights whenever the reverse gear is engaged.
BALL JOINT- Swivel joint that provides free movement for the steering knuckle and control arm.

BALL SOCKETS- Component that allows motion in up-and-down and side-to-side directions.

BAND- Metal strap with frictional material lining that can clamp a clutch drum in an automatic transmission to stop its rotation.

BAND ADJUSTMENT- Checking and altering tightness of automatic transmission bands as necessary for proper operation.

BATTERY- A device consisting of two or more cells for converting chemical energy into electrical energy.

BATTERY ACTIVATION- Filling and charging a dry-charged battery before installation.

BATTERY CABLES- The heavy wires connecting the battery to the electrical system of the vehicle.

BATTERY CAPACITY- The rating of the current output of a battery.

BATTERY CHARGE CONDITION- The state of the battery plates and electrolyte.

BATTERY CHARGER- A device for restoring a battery to a proper electrical charge.

BATTERY DRAIN TEST- A method of checking for unusual current draw with the ignition key off.

BATTERY LEAKAGE TEST- A check to determine if current is discharging across the top of the battery case.

BATTERY LOAD TEST- A test for battery capacity, made under full electrical load.

BATTERY TERMINAL TEST- A test for good contact between the cables and terminals.

BATTERY VOLTAGE- For batteries used in modern vehicles, 12.3 volts.

BATTERY VOLTAGE TEST- A check of the battery charge with a voltmeter.

BEARING NOISE- A constant whir or humming sound due to damage or wear of bearings in the carrier or axle assemblies.

BELTED BIAS TIRE- A bias-belted tire with extra belts added beneath the tread area.

BELTS- Fabric made of steel or other material that is placed between body plies and tread.

BENCH BLEED- Method of filling and hand pumping a master cylinder before installation to remove trapped air.

BIAS PLY TIRE- One with plies running at an angle from bead to bead.

BLEEDER SCREW- Fitting on the top of the brake caliper that allows air to be bled from the system.

BLEEDING- Process of removing any trapped air from a hydraulic system.

BRAKE BOOSTER- Component operated by vacuum or power steering system to decrease braking effort needed.

BRAKE LINES- Metal tubing and rubber hoses connecting the master cylinder to the wheel brake assemblies.

BRAKE PADS- Replaceable friction surfaces mounted on the caliper of a disc brake system.

BRAKE PEDAL ASSEMBLY- Foot lever for operating the brake system.

BRAKE PEDAL VIBRATION- Pulsing movement of the brake pedal, usually caused by out-of-round brake drum or warped rotor.

BRAKE SHOES- Curved, replaceable friction surfaces used with drum-type brakes.

BRAKE SYSTEM- Components that are used to
stop a vehicle.

BRAKE SYSTEM FLUSHING- Removal of all old fluid by pressure bleeding, then replacing it with fresh fluid.

BRAKE WARNING LIGHT- Dashboard indicator that warns of low brake system hydraulic pressure.

BRAKING RATIO- Comparison of front wheel to rear wheel braking effort.

BRAKE-AWAY TORQUE- The amount of torque required to make one axle rotate the clutches in a limited-slip differential.

BRUSHES- Sliding electrical contacts that ride on the slip rings of a generator.

BURNED FLUID- A condition caused by overheating due to slippage of the transmission bands.