Brake System: Notes

WARNING: This page is about a different car, the 2008 Ford RV Cutaway, 2008 Ford Econoline, 2008 Ford E450 Super Duty, and 2008 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

Applying the brake pedal uses lever action to push a rod into the brake booster, which through the use of hydraulic pressure or vacuum, boosts the force of the rod and then transmits this force into the master cylinder. This produces hydraulic pressure in the master cylinder. On vehicles not equipped with ABS, the hydraulic pressure is transmitted by brake fluid through the brake tubes to the individual brake calipers. On vehicles equipped with ABS, the hydraulic pressure is transmitted by brake fluid through the brake tubes to the ABS hydraulic control unit (HCU), which then distributes that pressure to the individual brake calipers. The brake calipers use hydraulic pressure to apply the pads. The application of the brake pads will cause the rotation of the wheels to slow or stop depending on how much brake pressure is applied. The parking brakes carry out the same function except that they are mechanically actuated by a cable that connects only to the rear brakes.

Depending on application, some vehicles will be equipped with a Hydro-Boost® brake booster and some will be equipped with a standard vacuum brake booster. The Hydro-Boost® system uses the power steering system to boost brake pedal pressure while the vacuum system uses engine manifold vacuum to boost brake pedal pressure. For a complete description on the operation of both systems, refer to POWER BRAKE ACTUATION article.