Maintaining your Craftsman riding mower is part of your responsibility for warranty coverage. This includes checking the tires, sharpening the blades, lubricating the tractor and drive belts. The mower blade drive belt is connected to the mandrel pulleys on the mower deck and to the engine pulley. Mower blade drive belts turn the cutting blades that cut the grass. Belts may become loose from use or improper placement. Craftsman riding lawn mowers do not have manual adjusters for mower blade drive belts, so the belts need to be replaced when they become loose.
Park the mower on a level surface such as a driveway. Turn the engine off and remove the key. Disengage the blades and lower the mower deck to its lowest level. Engage the parking break.
Remove the mower deck to access the mower blade belt. Remove retaining springs (cotter pins) located at the clutch (connected to the clutch rod), anti-sway bar (connected to the chassis bracket), suspension arms (attached to the deck brackets) and disconnect the front links. Raise the lever to the highest level and slide the mower deck from beneath the mower.
Remove the old belt. Slide it off the mandrel pulleys and the idler pulleys using your hands. Push belt guides out of the way as you work the belts off the pulleys. The mandrel pulleys are located centrally and to the left and right sides of the mower deck. The idler pulleys are located centrally to the front of the mower deck; there is one on each side and they are smaller than the mandrel pulleys.
Slide the new belt over the mandrel pulleys and then the idler pulleys. Make sure that the belt is completely in the grooves of the pulleys and inside the belt guides.
Push the mower deck underneath the body of the mower. Align the deck so that the suspension arms are aligned with the deck brackets, the clutch is aligned with the clutch rod, the anti-sway bars are aligned with the chassis bracket and the front links are aligned. Insert the retainer springs to secure the mower deck.