Sooner or later the plastic retaining strap that holds the fuel fill cap on Fox Body Mustangs will break. Here's a quick and easy way to fix it.....and it's free. First pry up on the black ring located on the inside of the cap. This ring holds the plastic retaining strap in place and allows the cap to rotate. Next, I used some Rubber Shower Liner found at any plumbing supply store (ask for free scraps!) and using the old piece as a template I traced around it with an xacto knife. Install the new strap and replace the black ring by simply snapping it back into place, and it still has that factory look!