How to Change Disc Brake Pads on a Car

First off I will start off by saying that every car is different. The most important step is safety. Make sure you have the tools you need close by. The car needs to be on a flat or level surface. Only work on one wheel at a time. If you are working on the front wheel brakes, chock the back wheels behind the car. If you are going to be working on the back brakes, chock the front wheels in front of the car.

Once you have secured the vehicle in park or locked in gear, loosen the lug nuts on the tire you are going to be working on. Do not take them all the way off yet, only break them loose.

Now you are ready to jack the car up. Most new vehicles have a lip or pad designed for this use. If you do not see one, try to find a place on the frame or axle where you can safely put the jack. The jack needs to be in a secure area, without coming into contact with any hoses, tubing, or wiring. If you are not sure about your placement, and the jack is not on any steering components, lift the vehicle a small amount and check the area you are lifting.

Never work under a vehicle with only one means of support. If you have to go under the vehicle you will need to use jack stands or some other mechanically locking device to keep the vehicle from falling. Hydraulic jacks can fail. Try to do all of your work from the side of the vehicle.

If you are satisfied with the support of the vehicle, continue raising it so that there is about one inch below the existing tire. Only lift the vehicle high enough to safely do your work.

Remove the lug nuts the rest of the way and put them in a safe location. Carefully remove the tire and face the outside towards the sky to avoid scraping or damaging your rims. Now you have access to your brakes.

The main components of your brake system in the wheel well are as follows: Rotor, brake line, caliper, and pads. The rotor is the big round piece of metal that has the lug bolts coming through it. Visually inspect the rotor anytime you have the wheel off. The only times rotors should have any grooves or holes is if they were manufactured that way. The bad grooves are the ones that make the rotor look like it could be a record. If there are grooves on the rotor you will need to take it off. The brakes will need to come off first.

To remove the brakes you will first need to remove the caliper bolts. Sometimes this will require a socket and wrench or a large Allen wrench. The bolts are located on either side of the piston casing. Usually you will have to reach behind the brake assembly to find these bolts. Once these bolts are removed you should be able to remove the brake assembly from the rotor. Use caution at this step because you do not want to damage the brake line. You may have to pry a little at the brake pads. Once the brake assembly is removed you can rest it on top of the axle or somewhere tension will not be on the brake lines. If you need to remove your rotor, now would be the time to do it.

If your rotors have never been removed before, there might be some sort of keepers on the lug bolts. These keepers are only for ease of assembly at the factory. You do not have to salvage the keepers. The easiest way I have found to remove them is a flat screwdriver and needle nose pliers. With the keepers off the rotor should be able to come off. Take your rotor to the local auto parts store. If they can turn them for you (grind the braking surface flat again). If not, replace it. Put your rotor back on.

To remove the old brake pads you will want to first want to compress the piston. For this use a c-clamp and the old pads you are getting ready to take off. Now that you have room to work remove the old pads. Make sure you pay attention to how the keepers are place and the orientation of the pads. Now you are ready to put the new pads on. If you paid attention to how the old ones were placed this should be fairly easy. Do not forget to put the keepers for the pads back the way they were. Once the brake assembly is back together place it around the rotor and slowly hand thread the caliper bolts back in to place until they are in at least five full turns. This is to prevent cross-threading. Tighten the caliper bolts to just a hair above snug, if you do not have a torque wrench. Look over your work just to make sure you didn't forget anything.

If everything went as planned you should be ready to put your wheel back on. When you put your wheel back on start your lug nuts by hand as far as you can or until you are sure they are not cross-threaded. When you tighten lug nuts it should be done in a star pattern or diagonally across from the nut you just tightened. Since the vehicle is still lifted you will not be able to completely tighten the lug nuts. Lower the vehicle so that the tire is just touching the ground and has traction. Tighten the lug nuts the rest of the way.

Once everything is tight you may lower the vehicle the rest of the way. Remove the chocks from the tires and put the jack out of the way.

Before hoping in and driving off, pump your brake pedal until it gets stiff again. Now lift the hood and make sure your brake fluid is at a good level. If everything is satisfactory you are ready for a test drive. Put the car in gear and allow it to move a little and be sure it will stop. If the vehicle stops good take it a little further down the road and check you brakes at about 15 miles per hour. You should be ready to go now.