Each time you use your Toro string trimmer to remove weeds and grass from your yard, parts of the cutting string are worn down and eventually fall off. You will need to repalce the plastic cord after enough use. You can either purchase a new, pre-wound spool of Toro trimmer line or find a suitable generic replacement at a home improvement store that you can wind on to the old spool. When purchasing non-Toro brand bulk line, it should be 0.065 inches--or 1.6 mm--in diameter.
Disconnect the trimmer for its power source. Twist the cap off the cutter head counterclockwise.
Remove the cap and spool. While you have the machine disassembled, clean out any debris from the yard that has collected on the cutting head and cap using a stiff brush or a rag.
Remove any line that is left on the existing spool. Hook one end of the line into the slot in the spool, leaving about 1/8 of an inch protruding out of the hole.
Wind the line in level rows between the flanges in the spool, using the arrow on the spool as your direction. Do not wind more than 30 feet of line on the spool.
Cup the rewound line gently so the line does not unwind. Insert the spool into the cutting head and thread the line into the eyelet. Holding the line and spool, replace the cap over the spool and twist it clockwise until it is secure.