Remove the air hose on the sander by pushing the chuck in slightly, pulling back on the metal chuck sleeve and then pulling the air chuck off.
Flip the sandpaper spring holder into the "up" position and remove the sandpaper. Also slide the foam backing pad off the base of the sander.
Use a screwdriver to take off the screws on the top of the air motor box located between the palm trigger and the sander base. This will separate the sander's base from the rest of the body.
Remove the screws holding the palm trigger to the air motor box and then set the palm trigger aside.
Remove the air motor box casing screws to access the inside of the air motor.