**A broad wooden block under the sofa’s solid frame is the simplest temporary fix.** Match the height of the other legs and place it near the damaged leg’s mounting point. It must sit firmly on the floor and support solid framing; fabric or thin underside panels cannot carry the load. Avoid using the sofa if the block can rock or slide.

From your description, the stud’s attachment inside the metal leg may have broken loose. A failed weld or retaining piece could explain it; a missing nut is only one possibility.

Before trying glue, check the sofa’s socket: with the sofa securely supported, try a good leg in that location. If it screws in normally, the damaged leg is the problem. If it also fails to catch, the sofa’s threaded fitting needs attention.

**Metal epoxy is a possible temporary repair** if the loose stud is still securely captive inside the leg:

1. Pull the stud outward gently and hold it straight.
2. Clean and dry the accessible metal around the stud and the cap’s hole. Roughen the bonding surfaces if you have sandpaper.
3. Apply two-part metal epoxy where the stud enters the cap, keeping the exposed threads clean.
4. Hold it upright and still until fully cured. Original J-B Weld specifies a 15–24-hour cure; allow the full 24 hours before installation. Follow the product’s preparation instructions. [J-B Weld instructions](https://www.jbweld.com/product/j-b-weld-twin-tube)

That may stop the stud spinning enough to install the leg. Its strength depends on what remains attached inside, so **don’t rely on glue alone if the stud can pull out or the leg still wobbles**. Keep the temporary block supporting that corner.

For a lasting fix, replace the leg with one matching its height, stud diameter, and thread pitch. Taking the damaged leg to a hardware shop makes matching the thread easier.