K 2500 Truck 4WD V8-379 6.2L DSL VIN C FI (1989)
Vacuum Pump: Description and Operation
These vehicles use either a belt driven or gear driven vacuum pump to aid the engine in maintaining a proper vacuum level for the power brake system
and other vacuum powered accessories.
The gear driven pump is a diaphragm pump that requires no periodic maintenance. This pump is driven by a cam inside the drive assembly on which
the pump is mounted. The drive housing assembly includes a gear on the lower end that meshes with the camshaft gear in the engine. This gear causes
the cam in the drive housing to turn. The gear also operates the engine oil lubricating pump.