I did a search and most of the topics that talk about repairing an old torn bellows are old, so I thought I would post how I have repaired mine.
First I went to a repair shop that specailizes in automobile tires and asked them if they had an old car tire tube. They gave it to me for no charge (saved them from having to pay to have it disposed of). At home I removed the bellows from the smoker, then the staples that hold the bellows together. Using the old belows material for a pattrern I cut out a new bellows from the tire tube and installed it onto the bellows. Reinstalled the belows onto the smoker and "vola" it's just like having a new smoker, only now the bellows is black rubber rather than some other material that is hard to spell.