Always replace all pads on both front wheels at the same time. Failure to do so will result in uneven braking action and premature wear.
The pad thickness should be inspected every time the tires are removed for rotation. The outer pad can be checked by looking in at each end, which is the point at which the highest rate of wear occurs. The inner pad can be checked by looking down through the inspection hole in the top of the caliper. If the thickness of the pad is worn to within 0.030 inches (0.76mm) of the rivet at either end of the pad, all the pads should be replaced. This is the factory recommended measurement; your state's automobile inspection laws may differ.
REMOVAL & INSTALLATION
Opening the bleeder before retracting the piston does require more time due to the need of having to bleed the brakes, but it really is the only correct way to install the pads. By not forcing old fluid up into the master cylinder you avoid forcing rust that forms around the seals from entering the master cylinder.
You want to avoid pushing the piston in with the bleeders closed, especially if the car has anti-lock brakes. Any rust that has formed around the seals will be forced up into the master cylinder or anti-lock brake system. This will cause severe abs problems.
- Siphon 2 / 3 of the brake fluid from the master cylinder reservoir. Loosen the wheel lug nuts and raise the car. Remove the wheel.
- Open the bleeder screws. If they won't turn soak them in penetrating oil and try again later.
- Position a C-clamp across the caliper so that it presses on the pads and tighten it until the caliper bottoms in its bore. Large slip joint pliers work well too.
If you haven't removed some brake fluid from the master cylinder, it may overflow when the piston is retracted.
- Remove the C-clamp.
- Remove the Allen® head caliper mounting bolts. Inspect the bolts for corrosion and replace as necessary.
- Remove the caliper from the steering knuckle and suspend it from the body of the car with a length of wire. Do not allow the caliper to hang by its hose.
- Remove the pad retaining springs and the pads from the caliper.
- Remove the plastic sleeves and the rubber bushings from the mounting bolt holes.
- Install new sleeves and bushings. Lubricate the sleeves with a light coating of silicone grease before installation. These parts must always be replaced when the pads are replaced. The parts are usually included in the pad replacement kits.
- Install the outboard pad into the caliper.
- Install the retainer spring on the inboard pad. A new spring should be included in the pad replacement kit.
- Install the new inboard into the caliper. The retention lugs fit into the piston.
- Install the caliper onto the steering knuckle. Tighten the mounting bolts to 38 ft. lbs. (51 Nm).
- Install the wheel and lower the car. Torque lug nuts to 100 ft. lbs. (140 Nm). Fill the master cylinder to its proper level with fresh brake fluid.