Glossary “vacuum vent valve” Definition:
Controls the induction of fresh air into a vacuum system to prevent chemical decay of the vacuum diaphragm that can occur on contact with fuel. The valve should be mounted with ports pointed downward for fuel drainback.

Glossary “vacuum testing” Definition:
Test on the intake manifold pressure to determine the condition of the pistion rings, valves, ignition timing and valve timing or to test for a restricted exhaust system.

Glossary “vacuum test” Definition:
Test to determine the presence of a vacuum.

Glossary “vacuum tap” Definition:
Point at which a vacuum can be released or measured from an enclosure.

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

Glossary “vacuum switch” Definition:
Electrical switch controlled by a vacuum.

Glossary “vacuum suspended power brake” Definition:
Power brake booster, in which vacuum is applied to both sides of the diaphram, neither apply additional force, or releasing any force, the booster is said to be suspended.

Glossary “vacuum suction cup” Definition:
Tool that uses a remote power source (separate vacuum pump or air compressor airflow) to produce a negative pressure (vacuum) in the spray gun cup. It also refers to a tool that is used pull out larger dent than can be done with just a suction cup.

Glossary “vacuum selector valve” Definition:
Vacuum valve that controls the vacuum motors, which, in turn, operate different vacuum operated components.

Glossary “vacuum secondaries” Definition:
Secondary bores of a four-barrel carburetor that are opened by a vacuum.

Glossary “vacuum retard delay valve” Definition:
Delays the loss of vacuum signal during some vehicle deceleration modes.

Glossary “vacuum restrictor” Definition:
Used to conrol the flow rate and/or timing actions to different emission control components.

Glossary “vacuum reservoir” Definition:
Container used to hold a residual supply of vacuum. Vacuum stored in the reservoir is used during periods when the engine is not producing sufficient vacuum to operate certain components.

Glossary “vacuum reserve tank” Definition:
A container used to store and provide reserve engine vacuum.

Glossary “vacuum regulator valve” Definition:
Vacuum regulator which provides a constant output signal when the input level is greater than a preset level. At a lower input vacuum the output equals the input. Some systems use 3-port or 4-port valves to control the vacuum advance to the distributor.

Glossary “vacuum regulator solenoid” Definition:
Regulator valve provides vacuum feedback to carburetor.