Glossary “primer” Definition:
Type of paint applied to a surface to increase its compatibility with the topcoat or to improve the corrosion resistance of the substrate.
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primary seal
Glossary “primary seal” Definition:
Seal between the compressor shaft seal and the shaft to prevent the leakage of refrigerant and oil.
primary shoe
Glossary “primary shoe” Definition:
The brake shoe toward the front of the vehicle in a dual-servo drum brake having a lining that may be shorter, thinner, and have different frictional characteristics than that of the secondary shoe.
primary surfacer
Glossary “primary surfacer” Definition:
A type of paint having a high solids content which fills small imperfections in body work and which usually must be sanded.
primary trigger
Glossary “primary trigger” Definition:
The electronic or electromechanical device that controls the switching of current flow in the primary windings.
primary vibration
Glossary “primary vibration” Definition:
When the piston slows down as it approaches TDC, its force puls the engine up. When it approaches BDC, it pulls the engine down.
primary resistance
Glossary “primary resistance” Definition:
Calibrated resistance wire or ballast resistor in a conventional ignition system inserted between the ignition switch and coil to reduce the primary voltage, after the engine has been started.
primary damage
Glossary “primary damage” Definition:
Damage caused by the initial impact of a collision.
primary pump
Glossary “primary pump” Definition:
The vaned, concave metal shell in the torque converter which drives the turbine through fluid force. Also known as “impeller”.
primary circuit
Glossary “primary circuit” Definition:
1). The electrical circuit of the low-voltage winding of the ignition coil. 2). The main fuel passages in a carburetor.
primary colors
Glossary “primary colors” Definition:
Red, yellow, and blue.
primary
Glossary “primary” Definition:
1). The low-voltage circuit of an ignition system. 2). The main drive chain; used to drive overhead cams, or used in transfer case applications.
primary air suspension system
Glossary “primary air suspension system” Definition:
Term used for a type of vehicle system that uses air, instead of coil, leaf, or torsion bar type springs, to support the vehicles weight.
primary brake shoe
Glossary “primary brake shoe” Definition:
Brake shoe in a set which initiates self-energizing action. Normally placed towards the front, and has less friction material.
pretreatment coating
Glossary “pretreatment coating” Definition:
A coating that contains no more than 12% solids, by weight, and at least 0.5 % acid, by weight. It is used to provide surface etching and is applied directly to bare metal surfaces to provide corrosion resistance and adhesion. The trade knows this item as metal conditioner.
prevailing torque nut
Glossary “prevailing torque nut” Definition:
Nut designed to develop an interference fit between the nut and bolt threads.
preventative maintenance (PM)
Glossary “preventative maintenance (PM)” Definition:
A systematic and scheduled inspection and service of a vehicle to ensure proper maintenance to provide a standard for satisfactory and sound operational conditions.
pressurized pot
Glossary “pressurized pot” Definition:
Also referred to as a pressure cup spray gun, it uses air pressure inside the paint cup or tank to force the material out of the gun.
pretensioner
Glossary “pretensioner” Definition:
Used to tighten the seat belt and shoulder harness around the occupant during an accident. Also used to maintain engine drive tension at the proper level.
pressurize
Glossary “pressurize” Definition:
To apply more than atmospheric pressure to a device or system.