How to Check Brakes

Updated: Aug. 27, 2019

Diagnose brake problems yourself

Family Handyman

Even if you have no experience repairing cars, you can check your brake pads and the condition of the rotors with these simple how to instructions.

By the DIY experts of The Family Handyman Magazine

Procedure for checking brake pads and rotors

Photo 1: Check the brake pad thickness

How to check brake pads: Measure the brake pad thickness by placing the compass points between the backing plate and the rotor. Measure the brake pad thickness at both the top and the bottom of the pad.

Photo 2: Check the rotor’s condition

How to check brake rotors: Run your fingernail across the rotor surface. If your nail catches in deep grooves, the rotors should be machined or replaced as a pair.

Here’s how to check your brakes yourself in two steps. First find a safe area to test your brakes and check for brake pedal pulsation. Brake to a stop from about 30 mph. The pedal should feel smooth with no pulsation at all. Then try braking at highway speeds. If you get pulsation, the rotors are “warped” and must be machined or replaced.

With the engine cold, remove a front wheel. Then use a compass and a tape measure to check the brake pad thickness (Photo 1). A new brake pad thickness is about 1/2 in. thick. Replace the pads when they get down to 1/8 in. Compare the readings top to bottom; they shouldn’t vary by more than 1/16 in. If they do, the caliper isn’t releasing properly and must be serviced. Finally, check the rotor disc for grooves (Photo 2). Next, check out: What are Drum Brakes and How do They Work?

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

Tape measure

You’ll also need a compass.

Originally Published: August 27, 2019