Brakes Basics: The Components in the Braking System

Your vehicle's braking system is an important piece of the safe-driving puzzle. Here we'll give you an overview of its many components, including the pros and cons of different types of brake pads. Some of this info may help you diagnose brake issues you may be having. If not, dig in deeper by troubleshooting your brake system. When you're ready to take on the repairs, here's a list of a few basic tools to get started.

Semi-metallic brake pads

Semi-metallic brake pads

Brake pads

Braking power may be severely reduced if your brake pads are worn thin. Worn brake pads are not only dangerous, but will cause expensive rotor damage if neglected. That said, knowing which kind of brake pad to use for your vehicle can be a challenge. So here's a brief overview of each and our bottom-line recommendations. 

Non-asbestos organic (NAO)

  • Pros: Inexpensive, quiet
  • Cons: Wear quickly

NAO brake pads are made with organic fillers like carbon, rubber, and Kevlar. The fillers dissipate heat and dampen vibrations. NAO brake pads are still standard on many vehicles because they work well, are inexpensive, and quiet. But, there's one major downside: they're soft and generally don't last as long as other more expensive formulations.


  • Pros: Stopping power
  • Cons: Noisy, dusty

Called “semi-mets” by the pros, semi-metallic brake pads are filled with metal fibers. The fibers pull heat away from the rotor and transfer it to the metal backing plate to reduce overheating and brake fade. That’s why semi-metallic brake pads provide ultimate stopping power. But, they’re not perfect.

Since they’re the hardest of all pad materials, semi-metallic brake pads tend to chew up rotors faster. They also make the most noise. In fact, semi-metallic brake pads are notorious for squealing during stops. And, they produce rusty, brown brake dust that’s guaranteed to dirty up your fancy, aluminum rims.


  • Pros: Stopping power
  • Cons: Range in quality

No one likes dusty, noisy brakes. Ceramic brake pads are designed to come as close as possible to the braking performance of semi-metallic brake pads, without the noise, dust, and worn brake rotor issues. A large percentage of new cars come equipped with ceramic brake pads right from the factory. But shopping for ceramic brake pads can be difficult because every manufacturer uses a different formula.

When shopping for ceramic brake pads, a higher-priced ceramic brake pad is an indication of its quality. In other words, don't replace a factory ceramic brake pad with an economy model and expect to get the same braking performance.

Bottom line on brake pads

The popular brake pad myth is that ceramic pads are always the best upgrade because they generate less noise and dust. Ceramic pads are a great upgrade from NAO, but manufacturers often install semi-metallic pads for a reason—because they provide the best braking for that particular vehicle's weight and brake design.

If you haul heavy loads or brake with a heavy foot, use semi-metallic brake pads. Don't second-guess the manufacturer and upgrade to ceramic brake pads without doing some further research. If you're set on using ceramic brake pads, replace your brake pads with the highest quality you can find.

Brake shoe

Brake shoe

Brake shoes

Brake shoes are the curved, metal friction plates pressing against the inside of the brake drums to slow the wheels. While disc brake systems are more effective, drum brakes are cheap to manufacture (and therefore cheaper to replace). Many vehicles feature a drum brake system on the rear axles and let the disc brakes take on the real heat in the front. Learn how to replace brake shoes.

Brake rotor

Brake rotor

Brake rotors

The brake rotor is the heart of your braking system and should be closely examined while planning any brake pad replacement. The cardinal rule: use high quality brake rotors. Economy brake rotors simply don’t perform as well as premium brake rotors. They contain less metal, are likely to overheat faster, and warp more often. Plus, the lower-quality metal increases your stopping distances. You’ll replace them more often, which will completely wipe out the savings advantage you thought you were getting when you bought them. All in all, you're better off replacing your rotors with the best ones you can the first time out.

Brake caliper

Brake caliper

Brake calipers

You may or may not need to replace the brake calipers during your next brake job. Here are a few things to look out for:

  • If the caliper is leaking, replace it.
  • If the piston dust boot is torn, chances are you’ve already damaged the piston seal, so you'll need to replace that, too.
  • If the caliper isn’t leaking and the boots are intact, the caliper is probably good to go for your next brake pad replacement.

Sometimes the square cut “O” ring inside the caliper can harden and prevent the piston from retracting. This can cause uneven brake pad wear (the outboard pad wears faster than the inboard because the caliper can’t release pressure). But, corroded pad slides and caliper pins can also cause uneven brake pad wear, and they’re much cheaper and easier to replace than a caliper, so try replacing those parts first. If you still have uneven pad wear, bite the bullet and buy a new caliper. Many semi-loaded calipers come complete with a rebuilt bracket (if equipped), caliper pins, pad slides, and new hose gaskets.

Brake hardware

Brake pads have to move in and out as they compress and release. If your vehicle is equipped with brake pad slides, replace them on each brake job. That’ll keep your pads moving smoothly and help prevent uneven pad wear long after your brake pad replacement. Buy a new brake hardware kit for each caliper.

Caliper pins

Every brake caliper slides on two pins. If the pins corrode, the caliper can’t “float” freely. This will result in braking noise, in addition to premature and uneven pad wear. If you seen any corrosion on the slide pins, toss the old ones and install new pins.

Caliper bracket

If your caliper pins are corroded inside the bracket, there's no way you're going to get them out and still have a usable bracket. Instead, just buy a rebuilt bracket. Brackets come with new caliper pins and rubber boots. Just slap one on and you're back in business.


Did we miss anything? Or do you have questions about the components? Let us know in the comments.

Last updated January 6, 2021