Brake pads are one of the many parts that ordinarily wear out in a car. They’re a regular maintenance item. If you hear metal-to-metal contact when you apply the brakes, that’s probably the brake-pad wear indicator. It’s a piece of metal on the pad that’s supposed to make contact with the rotor to purposely make a grating sound, to let you know that you that the pads need replacing.
Your first thought may be to take your car to the dealer or a neighborhood talyer. Thing is, there are times that the shops are full, the dealer sometimes takes too long, or you don’t have the budget for it.
Replacing brake pads is easy enough that it can be a DIY job. It’s going to be dirty, messy, and sweaty, but it’s not that hard, and it can be done by practically anyone who has the time and the aptitude to turn a wrench. By doing simple jobs like this yourself, you can save quite a bit of money. Also, they say it’s quite relaxing and fulfilling to work with your hands, especially when your occupation’s daily norm involves sitting in chairs within air-conditioned rooms, having meetings, and working on a computer.
But before we go to jacking up the car and taking the wheels off, we first have to be sure that the noise does indeed come from the brake pads and that replacements are now in order. This can be done in two ways. If the wheel design is open enough that you can take a peek into the brake calipers to see the side of the brake pads, go ahead and look at the side of the caliper to check pad thickness. If the wheel design won’t allow this, we have to jack up the car and take one of the wheels off.
Generally, the front brake pads wear faster than the rears, so check them first. During braking, the front brake pads generally do more of the work in slowing down the car. This is because the bulk of the car’s weight transfers to the front axle under braking. So, it’s best to jack the car up at the front, take off one of the front wheels, and check the brake pads up front first.
Once the wheel is off, we can take a peek at the friction material on the brake pad. We’re looking for a pad thickness between 3.2mm and 6.4mm. Fresh brake pads are at 12mm. Worn brake pads that are at 6.4mm and below need to be replaced. Once you’re down to 3.2mm, you’ll probably be hearing the metal-to-metal contact of the pad’s wear indicators scraping against the rotors. If the front pads are worn, there’s a good chance that the rear brake pads are also worn, and likewise, they should also be checked in the same manner.
Once we’ve determined that the brake pads do indeed require replacement, we need to go buy some new pads. Brake pad selection is a topic that can best be covered in a separate article for a complete discussion. For now, I will recommend original equipment manufacturer (OEM) pads. This is what the dealer and the manufacturer will recommend for your car. Go to the dealer’s parts counter or a store that sells parts for your particular brand of car, give your car’s year, make, model, and its VIN (vehicle identification number), and ask for the parts you need. In this case, ask for the brake pads that need replacing whether they be fronts, rears, or both. OEM brake pads will ordinarily also have a fresh set of clips, springs, and anti-squeal shims in the package with the pads.
Again, we need to jack up the car and take the wheel off. This time, we need to get the caliper out of the way by removing the bottom bolt behind the caliper, or both the bottom and top bolts behind the caliper. Depending on what kind of caliper your car comes with, you either swing the caliper up or take it off altogether. If it’s the kind that has to come off, you’ll need a piece of wire to hang it from your suspension. Please don’t let it hang from the high-pressure brake hoses as that may cause leaks. The photo below is an example of the caliper hanging by the brake line. Don’t do this. At this point, the brake pads, one on each face of the rotor, are now exposed and you can remove the clips and/or springs and slide the pads out. It may take some prying and coaxing, but they should slide out.
It’s a good idea to clean up the surrounding area like the rotors, the calipers, and the wheel well while you’re in there. You can hit the area with pressurized air, and a brush to remove dust, then hit the calipers and rotors with some brake cleaner. It’s also a good idea to measure the thickness of the brake rotors to see if there’s enough material left.
After removing the worn brake pads, we can now replace them with the new ones. Just do the reverse order of sliding in the new pads and installing the clips/springs and the anti-squeal shims. You should also have some high-temperature grease on hand and put a healthy layer in between the backing plates of the pads, the anti-squeal shims, and the caliper piston. If the new pads don’t fit, you may need to push the piston back a bit using a brake piston retracting tool, or a lever of some sort. Before doing so, remove the cap of the brake fluid reservoir first and line the area surrounding it with lots of cloth in case the fluid spills over. Brake fluid can damage a car’s paint. You’ve been warned.
Please do not apply the grease on the face of the rotors and on the face of the pads, only on the back of the pads, the shims, and the pistons. The grease reduces the resonance that’s produced when the pads hit the spinning rotor and that resonance is what can create a squealing noise when you apply the brakes. Once this is done you can reinstall the caliper and bolt it back up. You can now proceed to the wheel at the other side that also has worn pads.
I know it’s easier said than done, but it gets easier as you get used to it.