Disk Brake Pads, Rotor, and Caliper Replacement
This instructable covers how to replace every component of a disk brake system from the brake hoses down to the wheel axles. The pictures shown are from a Mitsubishi Lancer Evolution IX MR, but the steps and order will be the same for almost every other car. Disk brakes are a very simple system, so don't be afraid. Jump in and save yourself a ton of money by replacing brake pads and rotors yourself!
Tools you need:
Basic ratchet and socket set to fit your vehicle (metric for foreign cars and standard for American ones)
Box wrenches that fit the fittings on your brake hoses
A small punch or screw driver to remove the pins from the calipers
Oil catch pan
Shop towels (keep your new parts very clean to avoid screeching brake noises!)
Nitrile gloves are optional, but brakes are very dirty...I highly recommend them
Parts you need:
Brake pad lubricant (for the back side of the pad to keep it from squealing against the caliper)
Step 1: Removing the Caliper
Start by taking off the wheel. Be sure to use wheel chocks and a jack stand, be safe!
Once the wheel is off, look behind the brake caliper (the red thing in the picture). Place the oil catch pan underneath the caliper where the hose is connected. Disconnect the hose and let the brake fluid drain into the pan.
Next remove the caliper from the brake rotor. There are two bolts on this caliper to remove. One is hidden behind the hose at the top of the picture and the other is at the bottom of the picture to the right of the red tab. It will be very obvious what bolts to remove on your caliper. With the bolts removed, pull back and forth on either end of the caliper until it slides up off the brake rotor.
Step 2: Remove the Brake Hose
Place the oil catch pan underneath the brake hose connection. Place one wrench on the car side of the connection and one wrench on the hose side. Hold the wrench on the car side still while you turn the other wrench. This keeps the hose or tube on the car side from being damaged. After you've undone the connection the hose should come free. There may be a spring clip holding the hose in place, which can be removed by just pulling the clip. It may take a set of pliers or some prying with a screw driver.
Step 3: Attach New Brake Hose
Attaching the new brake hose is just the reverse of removing the old one. Again, hold the wrench on the car side still so you don't damage the hose or tube.
Step 4: Remove the Caliper
The front rotors of a car should pull right off the axle. Since you're replacing them, don't be afraid to use the hammer. Don't hit on just one side of the rotor, though. Tap around the edge or they will get bound up on one side. The rear rotors usually have an emergency brake hidden inside that makes them more difficult to remove. The secret is to use a small bolt in the empty hole. As you screw the bolt in, you will feel the rotor popping off the axle. You can see the bolt partially screwed in in this picture.
Step 5: Remove the Brake Pads
If your new calipers include spring clips and pins, then you don't need to do this step.
The brake pads are held into the caliper with two pins and a spring clip. Use the hammer and punch (or screw driver) to carefully remove the two pins from the caliper. Find the small side of the pin to hammer on, otherwise you're just smashing them further onto the caliper. The first pin you remove will release the tension of the spring clip, so be prepared for the punch or screw driver to get a little tangled.
Once the pins and spring clip are removed, the brake pads can just be pulled out of the caliper by hand.
Step 6: Install New Brake Pads
If your new calipers have the spring clips and pins installed, look at step 5 to remove them.
Spread a little bit of brake pad lubricant on the back side of the brake pads. Some pads come with plastic stickers, but I recommend using the lubricant as well. This lubricant keeps the pads from squealing when they vibrate between the rotors and calipers.
Push back the round silver pistons on the inside of the caliper to make room for the brake pads. With the pins and clips removed from the calipers, insert the new pads one at a time into the caliper. Some brake pads are meant for the inside or outside of the wheel. Be sure to put them on the correct side. One brake pad per pair also has a small metal tab on one corner. This tab is meant to touch the rotor when the pad is worn out, causing a squeal to warn you to change them. Make sure only one pad per caliper has this tab.
With the pads inserted, hold one end of the spring clip in place and insert one of the pins through the caliper. Repeat on the other end and the brake pads are installed.
Step 7: Installing the Rotor and Caliper
Clean away any dirt, dust, and debris from the car axle where the rotor attaches. Then slide the new rotor onto the axle until it fully seats. Don't use the hammer. I also suggest changing to a new set of gloves to keep your new rotors clean. This helps prevent squealing from debris caught between the pads and rotor.
When installing the caliper, make sure the bleed valve is at the top of the caliper (the bleed valve is a small cone shaped screw that's used to get air out of the system). With the rotor in place, carefully slide the caliper onto the rotor. Hold the brake pads apart and be very careful not to damage them while sliding the caliper onto the rotor. Keep going until you can get one of the bolts into the back side of the caliper that you removed in step 4. With the first bolt started, get the second one in and tighten them down.
Attach the brake cable to the back of the rotor. Make sure all the necessary washers and/or o-rings are in the right places or the hose will leak.
Step 8: The Wrap Up
After you've changed as many calipers, rotors, pads, and hoses as you wanted to, add the new brake fluid and bleed the system. I highly recommend draining all of the brake fluid out of the system and using brand new fluid. Brake fluid collects moisture and too much moisture makes the brake pedal feel spongy.
I'm not going to cover how to bleed your brakes here. There are plenty of other tutorials on how to do that. I do, however, highly recommend using a vacuum bleeder rather than the pedal pumping method. It gets the air out better and you can do the entire job yourself with the vacuum bleeder.