Things You'll Need
MTD Products is the manufacturer of the Bolens riding mower. Changing the belt on the Bolens mower follows the same procedure you would use for the MTD riding mower. The project is not difficult, and it requires no special tools to change the belt. The belt is subject to a great deal of stress under normal operating conditions and you should inspect it regularly. When you notice that the belt is beginning to crack, you should replace it.
Park the mower on a flat surface so that it is level when you work on it. Turn off the engine and set the parking brake. Allow the exhaust time to cool before you start work. Open the engine compartment by unsnapping the straps and rotating the cover forward.
Pull the wires from the spark plugs on the engine. Push the mower deck forward to lower the deck as far as possible. Remove the belt keepers using an adjustable wrench from around the engine pulley. Unhook the drive belt from the engine pulley by pulling it off.
Pull the hairpin clips from the mower deck hangers using a pair of needle-nose pliers. Tap the stabilizer rod free from the mower deck if yours is the 46-inch model using a hammer. This is the rod in the hinge-type bracket at the front of the mower deck. Pull the mower deck lever all the way back and slide the deck from under the mower.
Raise the seat and pivot it toward the front. Disconnect the cables from the battery, starting with the positive cable first, using a wrench. Locate the transaxle assembly by looking through the compartment where the battery sits. Loosen the nut on the pulley that you see using a 7/16-inch socket and ratchet, but do not remove it.
Remove the spring from the anchor bolt on the left side of the mower using a pair of needle-nose pliers to help you stretch it and pull it off. This will release the tension from the upper belt. Slip the belt from the transaxle pulley by pulling it off and away from the mower.
Remove the belt guide using a ¼-inch socket and ratchet by going through the battery compartment to get to it. Remove the belt keeper from the engine pulley using a ½-inch wrench. Remove the bolt from the crankshaft pulley with a 5/8-inch socket and ratchet. It may be very tight and could take some time to get it off.
Remove the engine pulley, lock washer and the flat washer using a socket and ratchet. Note the orientation of the parts before you remove them so that you know how they go back together. Pull the lower drive belt towards the engine and pull it off the mower. Be sure to note the proper routing of the belt. Install the new lower drive belt on the mower.
Spread anti-seize compound on the crankshaft but do not put it on the threads of the pulley bolt. Install the space on the crankshaft by sliding it into place. Install the crankshaft pulley and tighten the bolt using a torque wrench to 37.5 to 50 foot-pounds. Install the transmission belt into the upper pulleys in the "V" pulley. Make sure the belt seats properly.
Install the belt keeper around the engine pulley using a ½-inch wrench to tighten the fasteners. Install the belt keeper on the variable speed pulley using a ratchet and ¼-inch socket. Install the upper drive belt on the pulleys and make sure it seats properly on the pulleys. Install the tension spring on the left side of the mower using the needle-nose pliers.
Torque the nut on the transaxle pulley to 10 to 15 foot-pounds. Adjust the belt tension if necessary by removing the cotter pin from the ferrule on the variable speed pulley bracket with needle-nose pliers. Move the rod up or down as necessary and then replace the cotter pin into the ferrule.
Slide the mower deck under the lawn mower. Push the deck adjustment lever all the way forward so it is at the lowest position. Install the stabilizer rod by tapping it into the hinge bracket with a hammer if your deck is the 46-inch model. Connect the deck hanger links to the mower by installing the hairpin clips. These are at the back, center of the mower deck.
Loop the drive belt around the engine pulley. Install the belt keepers at the engine pulley using a wrench to tighten the bolts. Raise the mower deck by pulling the lever back and setting it for your cutting height. Lower the seat back down onto the mower. Plug the wires onto the spark plugs and close the engine compartment.