It looks like you tried to just screw a bolt in to set the thread-sert. If you don't have the correct tool, you can use a long bolt with a couple of lubed washers and a nut. You would hold the bolt still with a wrench then crank down on the nut to set the thread-sert. Most easy open tailgate kits for the 4th gens come with the bolt/washers/bearing/nut tool to do this.
I'll try to post a pic of what you need.