Replacing the belt for the motor on an older model of sewing machine is a simple operation and takes about 15 minutes. Be careful to purchase the appropriate size belt for your machine. These can be obtained from a sewing machine repair shop. Always check to make sure the power has been unplugged before servicing your machine.
Replacing a motor belt on an older model sewing machine
Unplug sewing machine. Disengage the drive for your machine so that you can rotate the side drive wheel without having the needle shaft move up and down. Remove bolts in back of sewing machine that hold the motor housing secure to the body of the sewing machine. Slip belt off end of motor drive shaft. Gently work belt loose from upper drive wheel on sewing machine body. You may have to work the wheel slowly forward to do this.
Take the new belt and, starting in the front, position it around the drive wheel of the sewing machine. You may have to slowly work the wheel backwards to feed the belt around. Make sure the belt is smooth side out and the gripper teeth are positioned to contact the drive wheel.
Slip the belt around the end of the motor shaft making sure there are no twists in the belt and that the gripper teeth are contacting the shaft. Re-secure the motor to the body of the sewing machine using the bolts. This may require a little muscle to reposition the motor because the new belt may be a bit tight.
Re-engage the drive for the machine so the needle will move up and down. Check to see the belt engages by turning the drive wheel of the sewing machine forward. This should cause the needle to move.
Always be sure the power plug has been removed from any electrical outlet before servicing your sewing machine.