The best time to inspect your car’s brake system is once you’ve done all the work of supporting the car and removing the wheel. At that point, a brake inspection takes just a minute or two at each wheel.
An automotive brake converts the car’s forward motion (kinetic energy) into heat energy through frictional force applied to the wheels. Excessive use of brakes can make them “hot” and subject to excessive wear or even a fire.
So how do you inspect brakes? It’s a procedure for making sure that you visually check the brake system’s components at each wheel. (The brake’s master cylinder was checked and fluid refilled in the Check Under the Hood Fix-It Guide.) You’ll be looking for fluid leaks, wear, and foreign objects.
There are two types of brakes used on modern cars: caliper and drum. Older cars had only drum brakes. Some newer ones use caliper brakes only. Most modern cars use caliper brakes on the front and drum brakes on the back of the car. Let’s take a quick look at each.
Caliper or disc brakes work similar to the rim brake on a bicycle. The driver presses on the brake pedal and the force is magnified by the hydraulic brake system to squeeze a stationary caliper against the rotating disc. The caliper has a brake pad on it that can be replaced once it’s worn.
Drum brakes use the same hydraulic pressure to push convex metal components called brake shoes against the inside surface of a drum that’s attached to the rotating wheel.
Brakes are relatively simple in function, but a little more complex in design. However, once you’ve identified the type of brake and how the major parts function, you can easily surmise how the secondary parts help. Further, you can visually inspect the parts to see if there are any problems.
Once the wheel rim is removed, you can see the major components of caliper brakes. However, to visually inspect drum brakes you must remove the drum. To do so, pull the drum toward you. Because of the force required to remove a drum, some consumers choose not to inspect the inside of drum brakes.
What should you be looking for when you inspect brakes?
- Look behind the wheel hub to find where the hydraulic brake line comes in and inspect the line for obvious wear or damage. (A mirror can be used to see behind the wheel without crawling around.)
- Look behind the wheel for wet or slick spots that could indicate leaking hydraulic fluid. If necessary, use a wrench to carefully tighten any fittings.
- Clean brake surfaces with a clean rag, clean paint brush, or compressed air. (Due to dust particles, wear a mask and goggles.)
- Visually inspect brake surfaces for obvious wear or damage. (An asphalt pellet from a newly paved road can lodge between brake surfaces and cause noises.)