Checking vacuum system for leaks

WARNING: This page does not describe the selected car, but rather 27 other vehicles, including the 2002 Volkswagen Cabrio, 2001 Volkswagen Cabrio, 2000 Volkswagen Cabrio, 1999 Volkswagen Jetta, and 1999 Volkswagen Golf. However, it is still accessible from the selected car via links, so may be relevant.

Remove driver's side instrument panel trim.
Refer to INSTRUMENT TRIM, REMOVING .
Remove vacuum hose from vacuum pump and seal end of hose.
Apply pressure to throttle control element diaphragm by depressing brake pedal by hand until resistance is felt.
Release brake pedal.
- Diaphragm must not move