Unplug the washing machine.
Shine a flashlight under the washer to inspect the drain pan. If you can reach the crack while the pan is under the machine, you can make a minor repair without removing it. Otherwise, turn off the water hose and, with the help of a second person, lift the washer and pull out the pan.
Scrub the crack with water and mild dish soap. Wipe the whole pan -- or as much of the pan as you can reach -- with a damp sponge.
Dry the pan with a dish cloth and allow it to air dry. Sand the crack with 220-grit sandpaper and wipe the dust away with a cloth that's been dampened with rubbing alcohol.
Mix the epoxy glue as directed. Apply the epoxy to the crack with a flat wooden stir stick.
Let the epoxy dry for about 30 minutes. Mix a second batch of epoxy and apply a second coat to the crack.
Allow the epoxy to dry for at least 24 hours before replacing and/or using the washing machine.