belt keeps com in off

Everytime I try to reposition the belt it keeps coming off. Do I need to replace it with a new one?

Here are your parts
http://www.appliancepartspros.com/partsearch/modelsearch.aspx?model=mah3000aww

Here is a service manual
http://www.servicematters.com/maytag_library/docs/16010061.pdf

See page 8-1