Yardman, which is a subsidiary of MTD, manufactures many yard-care tools, including riding mowers, edgers and string trimmers. Yardman string trimmers go where lawn mowers can't to remove overgrown grass and weeds with ease. Like many other models of string trimmers, Yardman string trimmers rely on a nylon string, rather than a blade. When the trimmer head spins, the nylon string cuts anything in its path. If the string repeatedly makes contact with hard surfaces, it will eventually break, and you must unwind more string from the spool, which houses approximately 25 feet of string. Replacing the entire spool is the quickest way to get back to work after the spool is empty.
Turn off the trimmer and lay it down with the head facing up.
Hold the outer portion of the spool still and turn the bump knob counterclockwise to unscrew it. Remove the bump knob to expose the inner reel.
Pull the old inner reel out of the outer spool and remove the spring from the bottom.
Transfer the spring to the new, pre-wound inner reel.
Insert the free ends of the string wound around the new inner reel through the eyelets on the outer spool.
Place the inner reel into the outer spool and push the two components together to lock them in place.
Grasp both pieces of the line and pull it firmly to release it from the holding slots.
Insert the inner reel and outer spool back into the trimmer head, then thread the bump knob onto the head, turning it clockwise.