Hose & Check Valve
WARNING: This page is about a different car, the 2004 Ford Thunderbird. However, it is still accessible from the selected car via links, so may be relevant.
The power brake booster check valve is located on the front of the power brake booster. Check valve is positioned between the power brake booster and the power brake booster hose. Valve closes when the engine is turned off. In the closed position, traps engine vacuum in the power brake booster. Check valve retains vacuum to provide several power assisted brake applications with the engine off.