I can't. Crest oil-free silent air compressor and vacuum pump both need air compression function, but their working principles and structures are not exactly the same. Vacuum pump needs to form negative pressure inside so that gas can be sucked and pumped out of the container, which usually requires special design and construction. If you need a vacuum pump, it is recommended to buy a vacuum pump product that suits your needs directly, instead of trying to transform an oil-free silent air compressor into a vacuum pump.