Glossary “pressure differential valve” Definition:
Valve used in a dual-brake system to turn on a dash warning light if the pressure drops in either part of the system.
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pressure drop
Glossary “pressure drop” Definition:
The loss of pressure due to a restriction, or the pressure required by a component to perform its designed task or function.
pressure control valve
Glossary “pressure control valve” Definition:
Device used to control and regulate the pressure of a system or sub-system.
pressure cycling switch
Glossary “pressure cycling switch” Definition:
Pressure switch that allows the magnet A/C clutch to be applied.
pressure bleeding
Glossary “pressure bleeding” Definition:
Bleeding the brake system using a pressure bleeder to charge the system.
pressure cap
Glossary “pressure cap” Definition:
Cap placed on the radiator to increase the pressure of the cooling system, to reduce cavitation and increase the boiling point of the coolant.
pressure
Glossary “pressure” Definition:
Force applied to a specific area, force per unit area or force divided by area, usually expressed in psi, psig, or psia (kPa or kPa absolute).
pressure balancing ring
Glossary “pressure balancing ring” Definition:
Compression ring having a ceramic coating to ensure sealing against the cylinder wall.
pressure bleeder
Glossary “pressure bleeder” Definition:
Device used to facilitate the removal of air from the brake system.
prep solvent
Glossary “prep solvent” Definition:
Fast drying solvent often used to clean a vehicle. It removes wax, oil, grease, and other debris that could contaminate and ruin the paint job.
press fit
Glossary “press fit” Definition:
Fitting of two parts with very close tolerances, one inside the other, generally by using a hydraulic press. Also known as force fit.
pressed fit
Glossary “pressed fit” Definition:
When two parts with an interference fit are forced together.
preload
Glossary “preload” Definition:
Pressure applied to a part during assembly or installation.
preload adjustment
Glossary “preload adjustment” Definition:
An adjustment when a bearing has an additional load placed against it after it is snug (zero-lash).
preload spring
Glossary “preload spring” Definition:
Part in a clutch assembly in a A/T that applies pressure to a clutch pack to help in the coupling action.
prelube
Glossary “prelube” Definition:
To apply lubricant to the parts of a rebuilt engine before starting it up.
premixed
Glossary “premixed” Definition:
Material that is ready to spray.
preheating
Glossary “preheating” Definition:
Heating the weld area of a metal before welding, to avoid thermal shock and stress.
preignition
Glossary “preignition” Definition:
The ignition of the air/fuel mixture in the combustion chamber by means other than the spark, usually caused by hot spots in the combustion chamber due to sharp edges, carbon accumulation, or spark plugs with a heat range that is too hot.
preheater
Glossary “preheater” Definition:
Glow plug that is used to heat the precombustion chamber of a diesel engine, to aid in cold weather start-up. May also be found on some EFE systems, mounted below the throttle body, and referred to as a preheater grid