Servicing disc brakes is actually fairly easy, even if you have little experience working on cars. Brakes require little in the way of special tools and equipment, and doing the work yourself can save you a substantial amount of money. For future reference, here’s the source of most disc brake problems.
Start by placing chocks behind the wheels. (If you do need to begin replacing parts on the rear brakes, you don’t want to engage the emergency brake.) Loosen the lug nuts, lift the car and remove the wheel to expose all of the parts for easy inspection and disassembly. Then, use this step-by-step to dig in.
Start With the Calipers
Caliper attachment varies from manufacturer to manufacturer, but most are bolted to a caliper bracket behind the rotor. Many have a carriage pin as part of the attachment bolt and include a rubber cover. Clean off any corrosion on the pin, lubricate the pin and check that the cover is intact, before reassembling.
Inspect Your Brake Pads
Use an inexpensive, easy-to-use brake pad measurement gauge to measure the brake pad thickness without disassembly. If your pad’s thickness reads between 3 mm and 4 mm, it’s time to change your brake pads.
If you’ve had an emergency stop from speed or have driven in conditions that required you to constantly ride your brakes (like descending a mountain slope or being towed behind another car with a strap) you should remove your pads to examine them for glazing. If they feel smooth or appear shiny or crystallized, replace them immediately.
Lubricate the Caliper Piston
Also inspect the rubber bellows that prevents water from seeping into the piston bore on the caliper. Cracks or tears allow corrosion to build inside, which can impinge the action of the piston. Lubricate the caliper piston, carriage pins and back of the pads with a little high-temperature brake grease, being careful not to contaminate the surface of the pads or rotors.
The Final Step: Inspect Your Rotors
Look over the rotor for signs of cracking and scoring. Typically, if the rotor has warped, you probably won’t be able to see it, but you’ll feel pulsation through the brake pedal when you apply the brakes. Replace the rotor if any of these issues are present. Also, note that before reassembly you should clean the hub surface of any corrosion (with a brake cleaner spray and a wire brush or with a 90-degree angle grinder with an abrasive wheel attached), making sure the rotor seats properly on the hub.
Time to re-assemble—you’re done! Well, almost.
Brake Fluid Flush
Has it been four or five years since your car’s last brake fluid flush? Then it’s probably time to do this, too, because water condensation in the brake fluid reservoir can mix with the fluid, diluting it, and potentially releasing air into the system. (Manufacturers’ recommendations range from 30,000 to 100,000 miles between fluid replacement.) A complete flush and fill removes impurities and any impurities and debris from your lines, too.
Bleed the Brakes
After your maintenance session is complete, if you notice a spongy feeling when braking, or if the pedal drops quickly underfoot before firmly engaging, you should bleed the brake lines. This process allows any air that has entered the system to escape and is DIY-friendly, though best done with an extra pair of hands for support.