How to Inspect Your Car’s Brakes — A Detailed Guide

Your car’s braking system is one of its most critical safety components, and understanding how to inspect it can save you from accidents, costly repairs, and breakdowns. This guide walks you through how to properly check your brakes — from what you hear on the road to what you see under the wheels.

1. Start With What You Hear and Feel

Before you even lift the hood or a tire, pay attention to how your car behaves during daily driving. If you hear a high-pitched squeal when you brake, it could be the sound of wear indicators on your brake pads — designed to warn you before they’re completely worn out. Grinding noises are more serious and may indicate that the brake pads are gone entirely, leaving metal components to grind against each other.

How the brake pedal feels underfoot is another key indicator. A soft or spongy pedal often means there’s air in the brake lines or your brake fluid is contaminated. A hard pedal could point to a faulty brake booster. If the pedal slowly sinks while your foot is on it, it may indicate a leak in the brake system or a failing master cylinder.

2. Visual Brake Pad Inspection

To physically inspect the brake pads, you’ll need to safely lift your car using a jack and jack stands and remove the wheels. Once exposed, you’ll typically be able to see the pads sitting inside the caliper, pressing against the rotor. Brake pads should generally have at least 3–4 millimeters of material left; anything less means it’s time to replace them.

Some pads have a wear groove down the middle — once that groove disappears, it’s a clear sign of excessive wear. Make sure to check both the outer and inner pads, as they may wear at different rates. Uneven wear could indicate a sticking caliper piston or seized guide pins.

3. Inspecting the Rotors

Brake rotors should have a smooth surface. Small grooves are normal, but deep scoring or a heavily worn lip around the edge suggests the rotor may be past its service life. Warping — often caused by excessive heat or improper lug nut torque — can lead to vibration when braking. This is usually felt through the steering wheel or brake pedal.

Using a micrometer or caliper tool, you can measure the rotor’s thickness and compare it to the minimum specification stamped on the rotor edge or found in your vehicle’s service manual. If it’s below spec, the rotor should be replaced, not resurfaced.

4. Brake Calipers and Hardware

Calipers are responsible for clamping the pads against the rotor. During inspection, check that the caliper moves freely (for floating calipers) and that the rubber boots around the piston aren’t torn or leaking brake fluid. Any visible leak or stuck caliper needs immediate attention, as it can lead to rapid, uneven pad wear or brake failure.

Also inspect the anti-rattle clips and caliper slide pins. Worn or seized pins can prevent the pads from retracting fully after braking, causing excessive heat and premature wear.

5. Brake Fluid: Quality and Level

Open the brake fluid reservoir under the hood (usually a translucent plastic container near the driver’s side firewall). The fluid should be between the “MIN” and “MAX” lines and appear light yellow or amber. If it’s dark brown or black, it’s likely contaminated with moisture and should be flushed. Brake fluid is hygroscopic — it absorbs water over time, which reduces braking effectiveness and corrodes internal components.

Never use the wrong type of fluid — check the cap for your vehicle’s specified type (DOT 3, DOT 4, or DOT 5.1), and don’t mix types unless they are compatible.

6. Inspect Brake Hoses and Hard Lines

While you’re under the car, inspect the rubber brake hoses that run from the calipers to the hard lines. Look for cracks, bulges, or leaks — especially near the fittings. These hoses expand slightly when braking, but any weakness can lead to a loss of pressure. Also check metal brake lines, especially around the wheel wells and chassis mounts, for signs of rust or corrosion.

7. ABS and Electronic Components

If your car has an anti-lock braking system (ABS), the dashboard light should come on briefly when you turn the ignition to “on,” then go off after a few seconds. If the light stays on or flashes, it may indicate an issue with the wheel speed sensors, ABS control module, or brake fluid pressure sensor. These systems are more difficult to inspect visually but can be scanned with an OBD-II reader for codes.

8. Drum Brake Inspection (if applicable)

If your car uses rear drum brakes, remove the drum (may require backing off the adjuster) and inspect the brake shoes for thickness. Also look for leaks around the wheel cylinder, uneven wear on the shoes, and weak or broken return springs. Like disc systems, these components must work smoothly to ensure even, safe braking.

Summary and Maintenance Recommendations

Brake inspections should be part of your regular vehicle maintenance routine — ideally every 5,000 to 7,000 miles, or twice a year. Change brake fluid every 2 to 3 years. Replace pads when they’re worn below 3mm, and always check rotors and calipers during the process. A good inspection now can prevent costly damage or unsafe driving conditions later.