Brake pads are a rigid block of friction material which, when activated by a foot brake clamp against a spinning rotor, slowing and stopping your vehicle.
The friction material on most brake pads is made from hard-wearing compounds of steel, copper, and graphite and then bound to a metal backing plate. High-performance brake pads are made from ceramic compounds and are generally more expensive. Organic brake pads made from organic materials are becoming more popular as they are less harmful to the environment.
The friction material wears with use, and the whole pad is designed to be replaced when worn; in times past, the pad would have been relined. Two brake pads per wheel are typical, and while all passenger vehicles use brake pads to the front, some basic models may fit brake shoes to the rear. Shoes do the same job as pads but go about it a little differently.
Where are Brake Pads Located?
Two brake pads (inner and outer) are located at the brake rotor behind each wheel (rotor only). The pads are largely canceled as they sit in a cradle clamped by the brake caliper.
That said, most passenger vehicles employ open-spoked wheels, which in most cases allows for brake pad inspection without removing the road wheel. I cover that exact topic right here in this short guide – How to check brake pads.
Pads are visible behind the wheel.
Common Brake Pad Problems
Brake pads are basic technology are don’t suffer from a ton of issues. The most common brake pad-associated issues include:
Brake Pads Worn
Brake pad wear is as normal as tire wear. The more we drive, the more likely, we’ll need to replace them. That said, no two drivers are the same. Some drivers are harder on brakes and some environments, too; take city driving, for example; it’s harder on brake pads as the brakes are used more often.
I’d consider normal brake pad replacement mileage to be somewhere between 25,000 and 30,000 miles. Brake pad lining below 3mm means it is time for new pads.
But things are changing, new regenerative brake systems fitted to hybrid and EVs offer minimal wear on the driven axles, (usually the front pads), the electric motor serves to slow the vehicle when in regen mode.
Brake Noise
We’ve all suffered from noisy brakes at some point. Brake pads have evolved and are a ton less noisy today than when I first started swinging wrenches. I’ve covered pad replacement here is this stepped guide – How to replace brake pads.
That said a smear of anti-squeal paste is best when replacing the pads.
However, the most common reason for brake noise is pad wear.
A metal tang designed to rub against the spinning rotor is a driver’s cue to make a pit stop for new brake pads.
Like nails on a blackboard.. it works.
But not all brake squeal is worn pads; some other causes include the following:
- Brake grime – clean and apply the anti-squeal paste
- Brake pad corrosion – replace pads (old pads metal backing plate corrodes)
- Trapped grit – remove grit (common after off-roading)
- Worn brake clips – replace clips (clips keep brake pads steady)
- Faulty caliper – replace caliper (sticking brake caliper can cause brake drag)
- Dry slid pins – lube pins (dry slide pins can cause brake drag)
- Subpar brake pads – replace pads
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John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.