Brake Repair Basics - Know Your System Components

How can you trust your mechanic to give you a fair price if you know nothing about brake repair yourself? The secret to protecting yourself from getting pushed around by auto technicians is through confidence and knowledge. If you want to take the power away from shady auto shops, start by learning about the main components of your braking system. That way, the next time you go in for a simple brake repair like pad replacement, you won't leave with new rotors and a master cylinder as well.

Most braking systems in modern cars, whether family sedans, trucks, or sports cars, will contain roughly the same parts with only a few minor differences. In the front of the car are disk brakes, which may also be in the back on some models (others will use drum brakes in the rear). All of the brakes are connected together via tubes that operate under the control of a master cylinder. The master cylinder is linked directly with the braking pedal. Every time a driver applies pressure to the pedal, fluid is released via a pump through the connecting tubes and pushes forcefully towards each of the individual disk brakes. Because the fluid is moving with such a high pressure (for the system to work properly, there should be no air in the liquid), it is powerful enough to stop a moving object.

The moving object in question that needs to be stopped is the rotor. Once the fluid is pushed on its way towards the disks, it hits the caliper, which looks like a clamp placed over the rotor and pads. The caliper's job is to "clamp" down on the rotor to stop its motion, which will ultimately stop the car's wheels from spinning. Pads are located on either side of the rotor and are attached to the calipers. These pads help grip the rotor to prevent damage that can occur. When the braking fluid hits the pistons within the calipers, the pads clamp and the rotors slow or stop depending on the pedal pressure the driver is giving.

So what are the signs that indicate you need brake repair? Every few years or 30,000 miles, most drivers will need to replace worn-out disk pads. Friction will eventually eat them away, and the calipers will be clamping down on the rotors without any buffer, which can cause damage. If you haven't had them checked or replaced in the past two years of several thousand miles, it's always safe to go ahead and do it. Additionally, a loud squealing noise during braking signifies wear.

A pedal that depresses to the floor too easily may be low on fluid. Braking fluid only depletes when the pads need replacement or there is a leak, so don't just top them off without inspecting the problem further. Another reason for a soft pedal could also be a problem with the master cylinder, which is a more expensive issue to address. Air in the fluid can be another cause, in which case the brakes will need to be bled.