How should I reattach the soles of my Chacos sandals that have split at the seam, horizontally?

I bought them about 3 or 4 years ago from a sporting goods retailer in St. Louis, Missouri. I do not have the chacos box they came in and I am sure whatever warranty they had, it has long passed. The sandals have not been worn that much, and appear relatively new(the soles are not worn and the straps are still strong). I do not need to replace the whole sole(like the Chacos website offers for $40 or so), just need to glue the two sections of the sole back together on both shoes.