Tips to Remove the piston: Remove the head, pull the piston out through chamber the piston head sits in. Remove the piston pin, located on the side of the piston, using a screwdriver or drill. The pin locks all piston assembly parts into place -- removing it allows you to disassemble the piston. Take the rings off the piston using a ring expander. This tool contains two handles and a large circular or U-shaped top. The top fits around or, in some cases, beneath piston rings and, when squeezed at the handles, opens the rings up for easy removal around the top of the piston.