Airtight Check

WARNING: This page is about a different car, the 2005 Nissan 350Z. However, it is still accessible from the selected car via links, so may be relevant.

Run the engine at idle for approximately 1 minute, and stop it after applying vacuum to the booster. Depress the brake pedal normally to change the vacuum to the atmospheric pressure. Check that distance between the brake pedal and floor panel gradually increases.
Depress brake pedal while engine is running, and stop engine with pedal depressed. The pedal stroke should not change after holding pedal down for 30 seconds.

CAUTION: Depressing pedal interval is approximately 5 seconds.

Fig 1: Checking Distance Between Brake Pedal & Floor Panel

Courtesy of NISSAN MOTOR CO., U.S.A.