Repairing a car's brake system is often regarded as a difficult process. However, the biggest challenge most often comes from diagnosing the problem. It is only once the source of the problem can be identified that it can be remedied. The fastest way to identify the source of a car's brake problem, or to at least eliminate some of the possible problems, it to determine what the brakes do or fail to do when the car is operated.
Pedal Goes to Floor
A car's brake system is based on hydraulic pressure. When a car's brake pedal can easily be depressed to the floor, the problem most likely lies with the hydraulics. The most common problem is an insufficient amount of brake fluid in the brake fluid reservoir. If the reservoir is full of brake fluid, then the problem is probably that there is air in the brake lines. Hydraulic pressure can also be lost if one or more wheel cylinders leak fluid, the brake lines are worn or loose or the master cylinder leaks.
Squealing Brakes
Squealing brakes are quite possibly the most common problem with car brakes. The squealing sound is almost always generated by a problem with a brake shoe or a damaged drum. Brake shoes use several different springs to hold them in place. Squealing often results if the shoe's retaining spring or return spring is either broken or weak. Brake shoes can also produce a squealing sound if the shoes become distorted, which usually occurs if the brake shoe has been used for too long. A defective brake drum will also produce a squealing sound if too much brake dust has accumulated inside the drum or if the drum is out-of-round (no longer true to its original circular shape). A squealing sound that emanates from vehicles with disk brakes can sometimes be traced to the rotor. If the vehicle is operated with severely worn brake pads, the rotor can get hot enough to warp, resulting in the squealing sound when the brakes are applied. Some vehicles are equipped with semi-metallic brake pads. Although this type of brake pad generally lasts longer, they do naturally produce a minor amount of squealing, particularly if the brakes are cold, such as in the morning hours. Less common sources of brake squealing include glazed or saturated brake lining, or brake lining that is the incorrect one for the particular car.
Dragging Brakes
Brakes are said to "drag" when they partially engage without the brake pedal being depressed. This is not to say that the car's brakes have frozen, but only that the brakes are causing a slight resistance, which can almost always be noticed by the driver. The culprit can almost always be traced to an adjustment problem, or to something as simple as either forgetting to disengage the parking brake, or a parking brake cable that is in need of adjustment. Other causes include a weak or broken return spring, brake fluid which has been contaminated with water, or a defective proportioning valve.
Brake Chatter
Brake chatter refers to a condition that, when the brake pedal is depressed, causes the car to pulsate. The problem gets noticeably worse the harder the brake pedal is depressed. Brake chatter is usually caused by either an out-of-round drum or distorted brake shoes. A loose or bent support plate can also cause the problem, as can contaminated brake lining. It should be noted, however, that brake chatter can also result from out-of-balance wheels.
Brake Fade
Brake fade is a condition used to describe brakes which lose partial effectiveness at high speeds. This does not mean that the brakes fail to work at all, but only that the brakes are not as effective at high speeds as they are at low speeds. Brake fade is usually cause by overheated brake drums or from using an incorrect kind of brake fluid, meaning that the fluid has a low boiling point.
