How your Mustang’s Brakes Work
Bolted to each wheel is a disc-shaped component called a rotor. Housed in U-shaped parts called calipers wrapping around each rotor are brake pads. When activated by the brake pedal, the pads press against the rotors to cause friction force that changes the energy of your Mustang’s motion to friction energy.
When you step on the brake pedal, the force you provide is sent to a structure mounted on the other side of the firewall between you and the engine called the master cylinder. The master cylinder is connected to the brake pedal by a lever that increases your mechanical advantage.
The master cylinder is filled with a specialized liquid called brake fluid. Between the master cylinder and the calipers are hoses to carry the pressure created at the master cylinder to the calipers. Some hoses are made of metal, but those near the wheels are constructed of rubber composite to allow steering and suspension movement.
Hydraulic principles allow the master cylinder/caliper interface to multiply the force the driver creates at the brake pedal. In years past, that was the whole story. Modern cars are also equipped with power brake boosters to magnify force from the brake pedal further to allow you to stop a 5000-pound vehicle with light pressure on the pedal.
Brake pads may be made of metallic, organic, ceramic, or composites. By design, pads lose a minuscule amount of their substance, but only when used. This accounts for why pads last longer for drivers who mostly put highway miles on their vehicles.
Pads are thick to give you many miles between replacements and absorb and transmit the heat friction force generates. When they wear thin, they can’t absorb and pass on this heat as well as new parts. Worn thin pads have decreased ability to slow you quickly. Pads worn to the metal backing will have little ability to slow your car and will damage the rotors.
Rotors are usually, but not always, made of steel. Steel is commonly used for its low price and ability to absorb lots of heat. Like brake pads, rotors can be bought with several different constructions. Like pads, rotors lose some of their substance as wear. The thinner rotors get, the less friction heat they can absorb from the pads and the less effective they are at slowing the car.
Brake Maintenance
Rotors and pads are thought of as wear items for a good reason. They must be replaced when worn past factory limits. Another wear item but not always considered is the brake fluid. Some of the heat generated from braking ends up in the brake fluid. Quality brake fluid will absorb lots of heat, but hot brake fluid readily absorbs water from the air.
Internal brake component passages are steel which will rust from contact with water-contaminated brake fluid. Brake fluid holds this rust until you have the brake fluid drained, flushed, refilled, and bled. Ford recommends brake fluid service every two years.
The calipers are among the parts that can lose effectiveness because of water-containing brake fluid. When these parts seize, your brakes become inoperative and will require replacement.
The steel brake lines are susceptible to this rusting, and the rubber brake lines deteriorate with age. A brake inspection will include a close look at these parts for possible replacement.
The master cylinder has seals that may leak, allowing fluid to escape and air to enter the system. If your brake pedal feels spongy, an inspection is essential. Air in the lines requires you to push the brake pedal further to stop. If the air remains in the system, eventually, the pedal will go to the floor, and braking action will be nil.
Your Ford has a warning light that notifies you of several brake problems. It may illuminate to tell you the brake fluid level is too low, for example. Consult your owner’s manual for a rundown on what conditions the brake light warns of, but do not ignore this indicator. The safety of your family and others depends on adequately working brakes.
Brake-Wear Warning Signs
Some pads include sensors to trigger the dashboard brake light or display a message. A metal scraper touching the rotor when pads are too thin is a standard low-tech warning. A grinding sound tells you the pads are worn to the backing plate and are metal-to-metal with the rotors. Ideally, you want to replace the pads before you hear this, but if you do, have your car towed to our shop.
You should change the brake pads and rotors before you notice these symptoms. A brake inspection along with oil changes is a great idea; pad life varies among drivers’ styles and types of driving. Bumper-to-bumper traffic wears out brake components faster than most people realize.
Up-to-date brakes are more critical than the engine. An inadequately serviced engine may fail, but poorly maintained brakes could be life-threatening. We have dedicated brake repair experts. Call us or visit our website to get a quote and book an appointment for a brake inspection or any service on your Mustang.
