ALT-1 How to Change Front Brake Pads
Once a car is moving, the most important thing to be able to do is stop it, safely, without damaging it, anyone or anything around it.
If you ignore that squealing noise coming from your front brakes, that's OK, it will go away, and the grinding noise, that too will go away; when your caliper piston pushes out far enough that you lose hydraulic pressure.
Most people don't let it get to that extreme. You should check your brake pads when you change your oil, so you know how they are every 3,000 miles.
When the brake pads get down to 1/8” thick, it's time to change them. When you get under that is when you start getting close to digging into your rotors. Each manufacturer is different, but it's a good rule of thumb.
Before you start. Find a solid level surface to work on.
Safety First! Place wheel chocks or blocks on the rear wheels. The car should also be in park with the emergency (or parking) brake set.
STEP ONE: Loosen the lug nuts before jacking up the car. DON'T take them off until you jack it up. Place the jack stands under a solid flat section of frame on each side of the car and lower the car on top of them.
STEP TWO: Remove the bolts holding the caliper to the bracket. Slide the caliper off the rotor. There's a piston inside that squeezes the brake pads into the rotor.
Do NOT let the caliper hang by the brake hose! This can cause the hose to collapse and on your test drive it will smell like your pads are burning because the piston will not release pressure when you let off the brake pedal. You can use a rope, cord or strap to hang it so there is no pressure on the hose while you are working with other parts.
Remove the brake pads and set pins or clips holding them to the caliper to the side so they don't get lost or stepped on.
Now inspect the rotor and decide if it will need to be resurfaced or replaced. The rotor is a metal disc that is mounted to the hub. It should have a Smooth finish, almost like a mirror. If they are scored, grooved or you were getting a pulsation when you stepped on the brakes, you need to have them measured and resurfaced, or replaced if they are not within specs. Your local parts store or machine shop can machine the surface smooth, so you will not have any chatter or pulsation when you step on the brake.
STEP THREE: If you need new rotors or needed the old ones resurfaced install them now. Make sure the hub is free of any rust or debris before installing the rotor, so it sits flat on the hub.
STEP FOUR: Before installing the new pads, the piston must be compressed back into the caliper. With the new pads at full thickness it will not fit over the rotor if not compressed. It's sometimes possible to compress it with large channel lock pliers or C-Clamp vise grips. If not a C-Clamp with a piece of wood or metal thin enough to slide in where the brake pad sits will work. On some cars the piston actually has to be twisted back into place. They make a tool for those, but it is possible to do by sticking needle nose pliers into the slots on the piston and twisting.
STEP FIVE: Apply the disc brake quiet spray or gel to the back of the brake pads, being careful not to get any on the friction surface that contacts rotor. This helps keep them from squealing from the heat produced during braking.
STEP SIX: Attach the brake pads to the caliper using the hardware you put aside earlier.
STEP SEVEN: Clean the caliper slides, bolts and brackets, making sure they are free of rust and debris. Then use the high temp grease to lubricate the slide, again being careful not to get any on the pads and rotors. Make sure the slides move easily in the sleeves.
STEP EIGHT: Slide the caliper back over the rotor and bolt it back in place.
Button it back up and take the car for a test drive to make sure everything works.
You may hear some scraping and scratching sounds. They will usually go away after a few miles.
