Check Air Tightness Under Load

With engine running, depress brake pedal. Then stop engine while holding brake pedal depressed.

Fig 1: Depressing And Holding Down Brake Pedal
Courtesy of SUZUKI OF AMERICA CORP.
Hold brake pedal depressed for 30 seconds. If pedal height does not change, condition is good. But it isn't if pedal rises.

Fig 2: Depressing Brake Pedal For 30 Seconds
Courtesy of SUZUKI OF AMERICA CORP.