Remove the loose stretcher from the chair. You may have to remove one or both of the legs of the chair to allow access to the loose stretcher. If required, use a screwdriver to remove the screws from where the leg or legs meet the base of the chair.
Scrape the old glue from the stretcher with a utility knife.
Apply wood glue to the area of the stretcher that you cleaned the old glue from. Reattach the stretchers to the legs of the chair and the legs to the base.
Place a band clamp around the legs of the chair to hold everything in place. Allow the glue to dry for at least 48 hours before removing the band clamp and using the chair.
Use a clean damp cloth to wipe away any excess glue that escapes from where you replaced the stretcher.
Examine the chair to see how the legs fit to the base. They are generally either attached with screws or glue. When attached with screws, it is often a simple matter of tightening the screws. If the legs are glued, however, you may wish to add a brace to help tighten the leg back to the base of the chair.
Use a screwdriver to tighten the screws of the leg that is loose until the chair no longer wobbles. To keep the other legs from becoming loose, check the screws on the other legs to ensure they are tight as well.
Fasten an angle brace to the base of the chair and the leg. Hold the leg of the chair in place against the base and pre-drill the holes on the leg of the chair for the angle brace. Attach the angle brace to the leg with screws. Insert a small piece of cardboard under the other side of the angle. Drill the screw holes for the other side with the cardboard in place. Place the screws into the hole and tighten slightly, but remove the cardboard before driving them in all the way. The gap cause by the cardboard will pull the joint together as you finish tightening the screws into the wood.