Turn off your Craftsman lawn mower, if it's on. Remove the bolts from the sides of the steering assembly cover using an adjustable wrench.
Locate the idle pulley at the top of the assembly, which looks like a small wheel connected to the control cable.
Unhook the spring end connected to the idler pulley using needle-nose pliers.
Disconnect the other end of the spring from the control cable. Hook the end of a new idler spring to the end of the control cable.
Connect the other end of the idler spring to the idler pulley end. Place the steering assembly cover back on.
Reinsert the bolts to the steering assembly cover and the part will be replaced.