Example: Good or bad vacuum supply to vacuum powered windshield wipers. (realclimate.org)
Rather than having a conventional vacuum powered brake booster, the Stevlio — like its close relative, the Giulia — uses an electric pump to build hydraulic pressure in the brake system. (evo.co.uk)
To improve the braking an 8» vacuum power booster master cylinder was also added. (barrett-jackson.com)