dont need special tool just open the bleeder valve and use a big screwdriver and turn the piston back in ,might want to put a hose on the bleeder valve and into a bottle to catch the brake fluid ,
once you got the new brake pads in make sure you lube the caliper pins with grease so that they dont wear out the new pads quickly
bleed the brakes you can use the bottle and hose to bleed the system your self just pump the pedal and watch until the air bubbles goes away and straight fluid is coming out ,dont forget to fill the mastercylinder with new fluid | 
