Inspect the sofa. Take all pillows and cushions off the sofa bed. Turn the sofa bed over on its side or front to check the underside for problems. Look for missing screws or cracked wood.
Tighten any loose screws. Use the appropriate tool such as pliers or a wrench for the form of screw the sofa bed has in place. Replace any screws that are missing from the frame or stripped.
Check for any cracked wood on the frame. Cut the desired size piece of plywood and use for a brace to repair the cracked or rotted wood. Lay the brace over the crack and screw the piece on with wood screws on each end of the brace to reinforce the sofa bed frame.
Open the sofa bed. Pull out the bed section of the sofa and check for any bent metal in the framework. Hammer the bent metal out straight.
Inspect the cushions of the sofa and check for any cuts or missing foam. Match sewing thread color to the color of the cushion cover and sew seams together with a needle. Unzip the cushions and fill with new foam padding commonly available at home craft stores.
Check sofa bed mattress. Sew up any holes or slits that the mattress may have received. A new mattress may be purchased if repairs are impossible.
Cover the sofa bed with a sofa slipcover available at many home retail stores if repairs cannot be made to the damaged sofa fabric.
Turn the sofa bed over right side up and sit. Check the braced frame and make sure it is steady. Make sure no foam or padding is coming out of newly sewed cushions.