Scott Hall shows you how to rebuild your Moroso Vacuum Pump. The nature of a vacuum pump is to remove, air, blow-by gasses and other contaminants from the crankcase of an engine. The vacuum pumps ability to remove the air in the crankcase results in overall engine vacuum. Vacuum will increase horsepower by allowing the use of low-tension compression and oil control rings. In which the use of reduces frictional horsepower losses, blow-by, intake charge contamination and aids in detonation prevention. Moroso’s “purpose built” racing pumps will need to be maintained to do this job effectively over the course of several racing seasons. Here’s how to Do-It-Yourself.