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.
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.”
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.