Your shoes take the brunt of use and abuse more than any other part of your wardrobe, so it is no wonder that over time the soles will crack, tear or separate from the main body of the shoes. Mending these soles with strong adhesive may be a faster and more economical option than purchasing a completely new pair of shoes. Minor damage can be repaired at home with clever use of caulk.
Pull the sole away from the shoe gently as far as it can go without causing more damage. This will expose all cracks and break lines in the rubber.
Wipe out the damaged area with a tack cloth or clean rag. This will remove dirt and dust from the area, allowing for better bonding between the rubber and adhesive.
Squeeze a thin bead of clear silicone caulk into the open area of the shoe. Add a bead to each break or crack line as well.
Quickly spread the caulk around with a flat putty knife or other such tool. Do not use your fingers, as this is an extremely difficult material to clean off. Spread the caulk to fill all cracks and breaks, as well as the entire separated surface of the sole.
Firmly press the sole back against the rest of the shoe. Clamp the pieces together to ensure a firm hold.
Clean off excess silicone caulk leaking from the joints with a damp cloth before it has time to dry. Allow the caulk to set overnight in the clamped position.
If the soles have completely separated from the shoe or are torn and broken beyond a simple fill-in job, contact a professional cobbler to resole the shoes for you. Other adhesives, such as strong glues, can also work to fix a rubber sole. Some shoe manufacturers may also offer adhesives for this project.