Regarding the use of Loctite, the most commonly sold formulations of Loctite are harmful to plastics. Loctite or cyanoacrylate superglues will damage and compromise the plastic gear, not creating a good repair and potentially leading to a split or break in the plastic. As an alternative to epoxy, or a product known to damage or eat plastics one might try an application of water-based acrylic paint after removing any oils or grease from the surfaces to be joined.