Driving with worn-out brake pads poses a hazard to both you and other drivers on the road. When the rear pads on a Ford Focus have worn beyond the point of effectiveness, a built-in "wear indicator" will generally alert the driver with a metallic squealing noise. Replacing the rear pads with new ones will restore the car's braking power to like-new condition.
Set the parking brake firmly and ensure the car is in park for automatic transmissions or first gear for manual transmissions.
Slide the jack under the frame. There is a crescent shaped marking to indicate where the jack goes. The owner's manual contains an illustration of this jacking point in more detail.
Raise the rear of the car until it is jacked up high enough to slide a jack stand under. Place the jack stand next to the jack and lower the car until its full weight is resting upon the stand.
Remove the lug nuts on the wheel and set them in a secure place. Remove the wheel, lay it on its side, and place it under the frame of the Focus. This serves as an extra precaution in case the jack stand fails.
Remove the bolts securing the caliper assembly. There are two of them, located directly behind the caliper. Be cautious when removing the last bolt to ensure the caliper does not fall to the ground, putting unnecessary strain on the brake line.
Pry the old brake pads out of the caliper and discard them. Using a "C" clamp, compress the piston inside the caliper to ensure there is room for the new, thicker pads. Insert the new pads by reversing the process used to remove the old ones.
Place the caliper back over the rotor and reinsert the two bolts previously removed, securely tightening them with a socket wrench.
Replace the wheel, ensuring each lug nut is installed tightly. Lower the car and remove the jack stand. Repeat these steps on the other side to change those pads as well.
If anti-squeal pads are not being used, a small amount of brake grease may be applied between the back of the pad and the caliper to reduce any potential squealing noises.
Never work on a car that is supported only by the jack. Take care not to damage the brake line.