Introduction: Change Disk Brake Pads
Changing your brake pads is a simple process that you can do yourself with just afew tools and a little time. This was done on the rear of a 94 Nissan Pathfinder but the tools needed and principle behind it can be applied to any disk brakes. I am not a certified mechanic and make mistakes as any human does. If you see I have done something wrong please politely notify me. With that being said I leave this.
Disclaimer: I am not responsible for any actions that you take that effect you. You are responsible for you. If you do something that hurts you or others, damages your property or others that is on you. Own up to the responsibilities of life. If you can't, don't do it.
Step 1: Tools and Materials
•Ratchet & sockets (metric in this case)
•Wrenches (also metric)
•One man brake bleeder kit (not totally necessary but makes things easier)
•Brake caliper compressor
•Lights (seems I always end up working on vehicles in the dark)
•New brake pads
Step 2: Safety
You don't want the vehicle falling on you and always should think of what the safest way of doing a project is before getting into it. Know the dangers you are dealing with and protect yourself as best as you can. Repeatedly assess the situation as you are in progress. Elements change and things can become dangerous quickly.
Chock the wheels to prevent the vehicle from rolling. I used 2 landscaping bricks I had and chocked one of the front wheels because the repair was going to be on the rear. Also note that parking brakes tend to only lock the rear and being that I was working there I did not apply the parking brake as I did not know if it would affect it but I didn't want any interference. If you are working on the front brakes I would recommend keeping the parking brake on.
Next remove the hubcap (if there is one) and break the lugnuts loose with your tire iron on the wheel you will be working on first. This will make removal of lugnuts much easier if they are broken loose now. If they are done after you have jacked up the wheel it will turn and will make it difficult to break loose.
Jack the vehicle up using a jacking point near the wheel you will be working on. Make sure you position the jack in a way that will allow you to place a jackstand near it to support the vehicle. You do not want to have the jack be your support for the vehicle.
Step 3: Remove the Wheel and Brake Pads
Now that your vehicle is in the air remove the lugnuts to free the wheel. Sometimes this can get stuck on the hub. Kick the tire if this occurs. Usually one good kick on one side of the tire will pop it off.
Once the wheel is out of the way you can see the brake rotor and caliper. The caliper should ride on a pin and a bolt. In my case the bolt is on the bottom and once removed you can pivot the caliper up on the pin. I secure the caliper up using bungee cords so that it is out of the way while I pull the pads out.
Step 4: Attach Bleeder Kit
The next steps are where things can get tricky if you dont have specialized tools. This part can be done with a little creativity without them but they do make it easier. First special tool is cheap and it is called a one man brake bleeder kit. It can usually be found for about 5 dollars at auto parts stores or tool stores. It is essentially some hoses and a collection bottle. You can get creative and improvise your own but for the price, ease of use and time saved I would recommend buying this when you pick up your parts.
Some may say this step is unnecessary. I had a friend who told me a "Two-necks" shop changed his pads and compressed his calipers without doing this and back pressure forced chunks of rust into his proportioning valve clogging it and leaving one of his front brakes inoperable (most of your stopping power is on the front). Creating a very dangerous condition for his family. Since then I have done this when changing my brakes.
This tool is designed to help you bleed your brakes without any one else there to assist. You will need to locate the bolt that has a small almost cone shaped nipple on it that is screwed into the top of your caliper. This is called a bleeder screw. Place one end of the hose over the end of the nipple. The other end of the hose connects to the bottle. The bottle has a magnet on it that allows you to attach it to a metal surface. I choose to put it on the frame or at some point above the caliper.
My reasoning for this is that you do not want air in your brake system. Air bubbles will rise in the liquid within the hose. If the bottle is lower the air bubbles will tend to stay at the caliper which you do not want.
Your brakes are a mechanical hydraulic system that when pressurized will force your caliper to compress and the pads to clamp on the brake rotor effectively slowing and stopping the vehicle. Liquid does not compress like air and if there is air in your system it will lead to your brakes feeling spongy and not reacting the way they need to. Air in brakes = bad for you.
Once you have attached the bleeder kit crack open the bleeder screw. This is best if opened while the caliper is in the original position so any air bubbles that are in the system will evacuate themselves because the bleeder screw is located to be the high point of the piston chamber in the caliper.
Step 5: Compress Caliper
This is a step that requires another specialty tool, a disk brake caliper compressor. You can borrow one of these from an auto parts store. They charge you for the tool and once you return it you get a full refund. You can also buy smaller simpler ones for cheap or use a large "C" clamp to compress if your caliper allows. The problem with using a "C" clamp is that you need even pressure on the piston and that is not easy to accomplish. If you are doing rear brakes many of them have a piston that has to be rotated as well as compressed hence the small "pegs" on some of the pieces of the kit pictured.
Place the compressor tool into the caliper with the rounded piece that fits your piston against it. Tighten the tool to open the gap for your new pads to fit. While you do this the fluid that is in the caliper should flow into your bleeder kit and fill the bottle. Keep an eye on the level in your bottle as you do not want it to overfill. The fluid should be clear and should not look like mine. If your brake fluid is not clear please flush your system until it is. It would be easy to do at this point and I would have if I had enough fluid but the bottle I had was too small for a flush and already half empty. Can't run to get more while my car is apart either.
Step 6: Replace the Pads
This step is pretty straight forward. Pull the old pads from thier positions and put the new ones in. Press them firmly against the rotor. Release the bungees holding the caliper up and drop it back to its original position. Close the bleeder by tightening the screw. Disconnect the hose from it. set kit aside. Make sure the fluid is all in the bottle when you do. If the hose is full of fluid and is set down lower than the bottle it will siphon and empty the bottle. Replace the bolt that holds the caliper.
Step 7: Wrap Up
You should be done with the one side now (see that wasn't so bad). Double check everything has been tightened and is back in position.
Find a container to place your used fluid into. An old brake fluid container would be ideal. While most auto parts stores advertise fluid collection they will not accept anything but oil. The city dump has a place for hazardous waste. Clearly mark your container and set it aside until your next trip there.
Replace wheel, pick up tools, remove jackstand and lower vehicle. Repeat on other side.
Once both sides have been completed and everything is back in order top off your brake master cylinder with new fluid. Close the cap. Press brake pedal once all the way to the floor. ONLY ONCE! Your pedal will not feel like it normally does and will go much further than normal. This is ok.
When you press your pedal it forces fluid from the master cylinder into your lines to the calipers. All the fluid you removed is being replenished with each pump of the brakes. Only press the pedal once before checking and topping off your master cylinder. If you run the master cylinder dry you will put air into your system and will have to bleed it out. Better to check after each pump and top off than to have to do that.
Pump, check, fill, repeat. Do this until your brake pedal feels firm.
Congratulations! you have successfully changed your own brakes! Total cost for me under 30 dollars for pads, and bleeder kit (because I misplaced my old one). Tack on brake fluid, a 40-60 dollar tool kit if you keep the rental or buy from "China Shipping", and you may even get lunch for less than the 100 dollar advertised minimum (they always try to upsell) you would pay a repair shop. You get the gratification of doing it yourself and learning something new. Plus you dont have to wait on them in their lobby and think the whole time "What's taking so long? I should've done it myself. . .This coffee tastes like crap. . . need something to wash that out of my mouth. . . damn vending machine is broken. . .Ahh popcorn will work to change the taste in my mouth. . . now im thirsty. . . this coffee really taste like crap. . .
Hope you aren't in that lobby now reading this instructable for the first time.
Thank you for reading, hope you have enjoyed.