First remove the screws which are holding these legs to the corners of the chair frame. Then check to see if the leg is holding properly with the original glue. If it isn't...then remove the leg and carefully clean of all the glued sufaces with a blade or single edged razor locked into a visegrip. You may or may not require sanding tro make sure that the surfaces are clean. Once the wood surfaces are clean, you can use Elmers carpenters glue for the cleaned up surfaces. Much easier to use than Gorilla Glue...which always expands and oozes out etc. Now, attache the leg back into position and use either NEW screws or the original screws. If you tighten the original screws and they don't TIGHTEN....then remove them and use NEW screws which must bite into the wood. These new screws may have to be slightly LONGER than the original ones. If any of the glue begins to ooze out of the joints, simply use a damp rag or paper towel to clean it up. I've repaired many chairs this way and I know that this process WORKS ! Try it ! BERNIE in Long Island NY