Glossary “vacuum check valve” Definition:
1). An air-operated mechanical device that closes a vacuum line to the vacuum reserve tank whenever the manifold vacuum pressure falls below the reserve vacuum pressure. 2). In a power-brake system, a one-way valve on the power brake boost that maintain vacuum within the unit when vacuum supply drops.

Glossary “vacuum check relay” Definition:
Mechanical, air-operated device that closes off a vacuum line to a port whenever the manifold vacuum pressure falls below the applied vacuum pressure.

Glossary “vacuum chamber” Definition:
Term used for vacuum canister or vacuum reserve tank.

Glossary “vacuum canister” Definition:
Tank like enclosure to serve the requirements of vacuum-actuated accessories.

Glossary “vacuum brake booster” Definition:
Device that uses vacuum to amplify the braking force.

Glossary “vacuum booster” Definition:
Power bbrake actuating mechanism that uses vacuum on one side of a diaphragm as a power source to amplify braking force.

Glossary “vacuum amplifier” Definition:
Term used for venturi vacuum amplifier.

Glossary “vacuum advance control” Definition:
An emissions-control system component that allows vacuum advance only during certain modes of engine operation.

Glossary “vacuum advance” Definition:
The principle of advancing ignition timing by using the vacuum generated by the engine, accomplished through the use of a mechanism attached to the distributor which moves the breaker point or pickup coil plate when it receives vacuum.