Brake Booster
WARNING: This page is about a different car, the 2004 Ford Ranger, 2003 Ford Ranger, and 2002 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.
All models are equipped with a dual-diaphragm vacuum booster. Boosters are self-contained, vacuum power brake units. Booster assists in actuating master cylinder push rod. See Fig 1.
The power brake booster is a dual diaphragm, vacuum assisted power brake booster. The booster is located on the left side of the bulkhead in the engine compartment, between the brake pedal and brake master cylinder. The booster is divided into separate chambers by the diaphragm. The booster will not operate if vacuum is restricted or if any of the vacuum related power brake components fail. The booster is replaced as an assembly. If the power assist fails, the brake system will continue to operate with increased brake pedal effort.