To replace rear Brake Pad, first and foremost you need to make sure that the fluid level in the master cylinder reservoir is adequate; if the level is somewhere in between the maximum and minimum points, then there is no need for removing any fluid. Jacking, tire, and wheel assembly removal. Hand tighten a wheel lug nut in order to secure a rotor on top of a hub. The additional notes concerning larger c-clamp say: "use a large c-clamp over the brake caliper with the ends against the rear of the caliper body and an old inboard Brake Pad, or a wood block against the caliper piston, tightening it until the piston was compressed enough to allow the caliper to slide past the rotor". First, remove the c-clamp, after that remove the brake caliper guide pin bolts, and hold the caliper in position using heavy mechanic's wire so as not to damage the hydraulic flexible brake hose. Lift off the calper from the bracket as well as the brake pads from the caliper bracket, examining the Brake Pad retainers. During installation, inspect the caliper slide boots for damage and replace if needed. Repeat the procedure of using the large c-clamp again to squish the caliper piston all the way into the bore after removing the clamp and the old pad or wood block. Mount the Brake Pad retainers and new brake pads in place, with the Brake Pad wear sensor installed properly. Reinstall the brake caliper to the bracket, and screw the guide pin bolts into place, and tighten them to 31 nm (23 ft. Lbs.). Change back the tire and wheel assembly, lower the vehicle, and with the engine shut off, slowly apply the Brake Pedal around 2-3 of its stroke, then slowly let go of it. Hold the pedal until you can feel it firm up, wait 15 seconds, and repeat until the caliper pistons and pads are seated properly. Finally, top up the brake master cylinder reservoir to the right level and burnish the pads and rotors.