Gimme a Brake!

Of all the parts on a car or truck, the ones most closely connected to the safety of the driver are, in my mind, the brakes. The braking system is what we rely on to not only stop the vehicle, but slow it down as well. The two basic types of brake systems are the pad and rotor, and the shoe and drum styles. The older of the two is the drum and shoe which employs a shoe which fits inside of a round drum and is pressed against the inside of the drum by a hydraulic component known as a wheel cylinder. The wheel cylinder is operated by the master cylinder inside the engine compartment which sends pressure by way of brake (hydraulic) fluid to the wheel cylinder pressing the shoe into the drum. The pad and rotor system is the newer of the two and consists of a set of pads which are pinched into both sides of a metal plate we call a rotor. The pinching is performed by a caliper in which the pads are mounted and which like the wheel cylinder is operated by hydraulic pressure from the master cylinder. Virtually all modern cars are equipped with disc brakes in the front, while the rear can be either disc or drum in the rear. However, most cars today are four wheel disc and drums are found more frequently on trucks.

Brake shoes are made of a resin in which metal, ceramic and asbestos (YES, they still put some asbestos in brakes) are embedded. The same goes for brake pads, though no asbestos is used in them. The most recent development is the use of ceramics in pads as the substance is quieter and produces less dust than metallic particles. It costs a bit more to get ceramic pads than the better known “semi-metallic” type but most people find them to be superior in operation. Our experience, however, is that ceramics are a softer material and do not last quite as long as the semi-metallics. This is especially true in heavier vehicles such as police cars and trucks which expose the brakes to greater stresses and production of heat from friction.

Anti-lock brake systems are the newest addition to most cars and trucks. It consists of a computer controller which pulsates the application of the brakes in the case of a skid. No more need to pump the brakes on ice as the controller of the ABS system does it for you.

The fluid in the brake system is a true hydraulic fluid and can age. As it ages, it can collect water which causes it to lose its efficiency. In fact, it is hydroscopic, meaning it attracts the humidity in any air that it is exposed to and traps it, thus weakening itself. Also, the rubber components in the system can break down a bit with age and be absorbed into the fluid. For that reason, most people suggest changing out the fluid every 25,000 to 30,000 miles to assure that the fluid will operate at peak performance.

It is a good idea to get your brakes inspected once or twice a year to be assured that they are in proper working order. This can be accomplished at the same time you rotate your tires and will save you time and $$$ in the long run by doing both at the same time.