Brake pads are one of the most important wear items on any vehicle. They are also one of the most common DIY repairs, making them a great starting point if you are learning to work on your own car. This guide covers how to inspect your brake pads for wear, when to replace them, and the step-by-step process to swap them out.
How Disc Brakes Work
When you press the brake pedal, hydraulic fluid pushes pistons inside the brake caliper. These pistons squeeze the brake pads against a spinning metal disc (the rotor), creating friction that slows the wheel. Over time, the friction material on the brake pads wears down and needs replacing.
Most modern vehicles use disc brakes on the front wheels (where most braking force is applied) and either disc or drum brakes on the rear. This guide focuses on disc brake pad replacement, which is the most common job.
Signs Your Brake Pads Need Replacing
- Squealing or squeaking when braking. Most brake pads have a built-in metal wear indicator that contacts the rotor when the pad material is low, producing a high-pitched squeal. This is your early warning.
- Grinding noise. If you hear metal-on-metal grinding, the pad material is completely worn through and the backing plate is contacting the rotor. This damages the rotor and requires immediate attention.
- Brake pedal feels soft or spongy. While this can indicate air in the brake lines or a fluid leak, extremely worn pads can also cause increased pedal travel.
- Vehicle pulls to one side when braking. Uneven pad wear between left and right sides can cause the car to pull. This may also indicate a stuck caliper slide pin.
- Dashboard brake warning light. Some vehicles have a brake pad wear sensor (a small wire embedded in the pad) that triggers a dashboard warning when the pad reaches minimum thickness.
How to Visually Inspect Brake Pads
You can check your brake pad thickness without removing the wheel on most vehicles. Look through the spokes of the wheel at the caliper. You should be able to see the edge of the brake pad where it contacts the rotor. If the friction material (the darker part) is less than 3 mm (about 1/8 inch) thick, it is time to replace them.
For a more accurate measurement, remove the wheel and use a vernier caliper to measure the pad thickness. Your vehicle’s workshop manual will list the exact minimum pad thickness specification, which is typically between 1.0 mm and 2.0 mm depending on the manufacturer.
Tools and Parts You Will Need
- Jack and jack stands (never work under a car supported only by a jack)
- Wheel lug wrench
- Socket set or spanners (typically 12 mm to 17 mm for caliper bolts)
- Brake caliper piston retraction tool or a large C-clamp
- Brake cleaner spray
- Copper-based brake grease (for slide pins and pad backing plates)
- New brake pads (always replace both sides of the same axle)
- Wire or bungee cord to support the caliper
Step-by-Step Brake Pad Replacement
Step 1: Prepare the vehicle
Park on a flat, level surface. Loosen the wheel lug nuts slightly before raising the vehicle. Raise the vehicle with a jack and secure it on jack stands. Remove the wheel.
Step 2: Remove the caliper
Locate the caliper bolts (also called slide pin bolts) on the back of the caliper. There are usually two bolts, one at the top and one at the bottom. Remove the lower bolt (and sometimes the upper bolt depending on your vehicle) and swing the caliper upward or slide it off the bracket. Use a wire or bungee cord to hang the caliper from the suspension spring or strut. Never let the caliper hang by the brake hose, as this can damage the hose internally.
Step 3: Remove the old pads
The old brake pads will either slide out of the caliper bracket or be clipped to the caliper itself, depending on the design. Note how they are positioned, including any shims, springs, or anti-rattle clips. Take a photo with your phone before removing anything so you can reassemble correctly.
Step 4: Retract the caliper piston
The new pads are thicker than the worn ones, so you need to push the caliper piston back into its bore. Use a brake caliper piston tool or a large C-clamp, placing the old pad against the piston face to distribute the force evenly. Push the piston back slowly and steadily. Before doing this, open the brake fluid reservoir cap slightly to prevent pressure buildup. Watch the fluid level in the reservoir as you retract the piston, as it will rise.
Important note for rear brakes: Many vehicles with rear disc brakes use a screw-type piston that must be rotated clockwise while being pushed in, rather than simply pushed straight back. Check your workshop manual for your specific vehicle, as forcing a screw-type piston straight in will damage the caliper.
Step 5: Install the new pads
Clean the caliper bracket with brake cleaner. Apply a thin film of brake grease to the slide points where the pad ears contact the bracket. Install any new anti-rattle clips that came with the pad set. Slide the new pads into position, making sure any wear indicator tabs face the correct direction (usually toward the inner pad).
Step 6: Reassemble
Lower the caliper back over the new pads and onto the bracket. Reinstall and tighten the caliper bolts to the torque specification listed in your workshop manual (typically 25 to 40 Nm for slide pin bolts, but this varies significantly between vehicles). Refit the wheel and lower the vehicle.
Step 7: Bed in the new pads
Before driving normally, pump the brake pedal several times until it feels firm. This takes up the slack created by pushing the piston back. Then drive at low speed and perform several gentle stops from 50 km/h to let the pads bed into the rotor surface. Avoid hard braking for the first 200 km.
When to Also Replace the Rotors
Brake rotors also wear over time. If the rotor has a visible lip at the outer edge, deep grooves scored into the surface, or measures below the minimum thickness stamped on the rotor casting, it should be replaced along with the pads. Your workshop manual will list the minimum rotor thickness and the maximum allowable runout (typically 0.05 to 0.10 mm) measured with a dial indicator.
Why a Workshop Manual Matters for Brake Work
Every vehicle has different caliper bolt torque specs, minimum pad thickness limits, rotor specifications, and piston retraction methods. Getting these details wrong can compromise your braking safety. A vehicle-specific workshop manual gives you the exact numbers and procedures for your make and model.
MechanicMate offers workshop manuals for popular makes including Toyota, Nissan, Mazda, Mitsubishi, Ford, Hyundai, and Honda. Each manual includes the brake system chapter with pad replacement procedures, torque specs, and rotor specifications for your exact vehicle. Browse our full range at mechanicmate.net/shop.
