I have a metal threshold that was previous connected to the cement foundation using glue to attach a strip of wood to the cement, then the threshold was screwed into the wood. The threshold has come loose and attempts to reglue the wood have been unsuccessful because there is a large crack in the cement that expands the entire wide of the door from jam to jam. The crack varies in width at it's largest dimension is about 1/2 wide. I have tried clean out the cement crack and fill with quickcrete which did not set-up. I have tried lag bolts in the cement, but the crack is too wide to hold the lag bolts. Multiple trips to the hardware store and Home Depot have given me the idea of using premixed concrete crack filler, then liquid nails to attach the wood in which I can screw down the metal threshold.
Another idea was to fill the crack with epoxy that is used to hold rebar and reinforcements in cement, then use liquid nails to glue the wood. then attach the threshold.
Any suggestions? Should be some way to fix this without buy a whole new door with threshold attached.
A couple of things come to mind. First, filling in the crack seems like a good first step. However, be sure that you do this with a good quality epoxy patching compound, rather than with cement which will never stick.
Second, have you tried TAPCON fasteners? These can be drilled right into the concrete and have excellent holding power, in concrete or in the epoxy repaired areas. Attaching the threshold directly to the concrete will also give you much better holding power than any adhesive.