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How to tell if your car needs a brake job

Measure your brake pads and discs quickly and easily to find out which kind of brake job you need.

Brian Cooley Editor at Large
Brian Cooley is CNET's Editor at large and has been with the brand since 1995. He currently focuses on electrification of vehicles but also follows the big trends in smart home, digital healthcare, 5G, the future of food, and augmented & virtual realities. Cooley is a sought after presenter by brands and their agencies when they want to understand how consumers react to new technologies. He has been a regular featured speaker at CES, Cannes Lions, Advertising Week and The PHM HealthFront™. He was born and raised in Silicon Valley when Apple's campus was mostly apricots.
Expertise Automotive technology, smart home, digital health. Credentials
  • 5G Technician, ETA International
Brian Cooley
2 min read

I don't know about you, but every time the shop tells me I need brakes it feels like I swear I just got them done not long ago. And since brake jobs are often preventive maintenance, your car may drive about the same as it did before the expensive work was done. Not very satisfying, and you may question whether you really need a brake job. In this video I'll show you how to satisfy yourself that you do -- or don't -- need the most common brake work: Pads and rotors.

For this quick diagnosis you merely need the skills to change a flat tire; There's no need to remove any brake parts. Jack up and secure the car, then pull off one of the wheels where the brake work is needed (front or rear) and measure the thickness of the one brake pad and of its brake rotor, commonly called a disc. You can do this in about 2 minutes once the wheel is off.

You'll need a couple of inexpensive tools you may not have around the house: A pair of calipers and a brake lining thickness gauge. The calipers are for measuring the thickness of the brake rotor, while the brake lining thickness feelers measure the thickness of the pads. 

Lisle brake lining thickness gauge

A simple set of plastic feelers like this can quickly tell you the thickness of your brake pads and give you a color-coded indication of their remaining life.


The calipers you need are a type with long fingers that can reach to the correct part of the brake rotor, called the swept area. In the video I show you what that looks like and why you need to measure it. You'll immediately see why you need a pair of calipers with long "fingers."

Brake rotor calipers

These long-reach calipers have "fingertips" designed to easily measure the thickness of brake rotors.

Harbor Freight

The brake lining thickness gauge is a simple set of feelers you place against the brake pad until you find the one that is the closest match to the pad thickness, revealing the approximate amount of brake pad left. 

You compare these measurements against the specs for your car: The minimum rotor thickness will vary by make and model of car. Brake pad measurements, however, are pretty universal: 3 millimeters or less of pad thickness means you need to replace pads now or soon. 

Most shops aren't trying to rook you, but I know that some cars -- looking at you German makers -- go through brakes so fast you'd swear it's an expensive Groundhog Day scam. Now you can quickly put your mind at ease.