Ford Mustang (1999-2004) Service Manual: Brake Booster - Vacuum (Description and Operation)

Power Brake Booster

The vacuum type power brake booster (2005):

• is a dual diaphragm, vacuum assisted power brake booster
• reduces brake pedal force and travel distance.
• is located on the LH side of the bulkhead in the engine compartment, between the brake pedal (2455) and the brake master cylinder (2140).
• is divided into separate chambers by the diaphragms.
• will not operate if vacuum is restricted or if any of the vacuum related power brake components fail.
• is installed as an assembly.

If the power assist fails, the brake system will continue to operate with increased brake pedal effort.

Hose and Check Valve

The power brake booster check valve (2365):

• is located on the front of the power brake booster.
• is installed separately; (install a new grommet when installing a new check valve).
• is positioned between the power brake booster and the power brake booster hose.
• closes when the engine is turned off.
• in the closed position, traps engine vacuum in the power brake booster
• retains vacuum to provide several power assisted brake applications with the engine off.