Automotive Glossary of Terms - U -
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Definitions for automotive terms and illustrations from universal joint to unsprung car weight.
U-JOINT (UNIVERSAL JOINT): A flexible coupling in the drive train that allows the driveshafts or axle shafts to operate at different angles and still transmit rotary power.
ULTRAVIOLET LIGHT: A light used in conjunction with a fluorescent dye to detect leaks in the engine, transmission or cooling system.
UNDER LOAD: Used to describe the condition of a vehicle when climbing a steep incline or hill. When the vehicle is placed under a higher than normal amount of load when carrying excessive cargo.
UNDERSTEER: The tendency of a car to continue straight ahead while negotiating a turn.
UNIT BODY: Design in which the car body acts as the frame.
UNLEADED FUEL: Fuel which contains no lead (a common gasoline additive). The presence of lead in fuel will destroy the functioning elements of a catalytic converter, making it useless.
UNSPRUNG CAR WEIGHT: The weight of car components not supported by the springs (wheels, tires, brakes, rear axle, control arms, etc.).