Switch off the power to your washing machine and unplug it from the wall outlet. Drag the washing machine away from the wall so you can access the rear.
Detach the water hoses and pipes that siphon water outside of the house.
Put some old towels or sheets on the floor before starting work on the washer belt. Washing machines usually have some water still in the system even when unplugged and not running.
Take off the rear access panel. This is usually situated at the back of the machine on the bottom left or right side. Use a screwdriver to remove the screws that hold the panel in place.
Identify the washer belt. The belt is dragged over a wheel mechanism that is linked to the washing machine motor.
Loose the washer motor. Grip the nut that holds the motor in place with a monkey wrench and turn in an anti-clockwise direction until it starts to loosen.
Push down on the motor to exert pressure on the belt and make it tighten around the wheel. Tighten the motor nut with the wrench whilst pushing down on the motor.