I have 2006 Ford Focus. The sheet metal on the bottom is rather large, and it fell off again. Before, I had secured it with bolts and over-sized washers. But now, the areas around where the sheet metal is supposed to be secured to the underbody have frayed so much, I cannot fasten the heat shield again by using the existing posts and nuts. I am thinking about using self-tapping machine screws to fasten the heat shield onto the underside.
My questions are:
- Is it O.K. to drill holes on the underside of the car? I am concerned about the new holes rusting out and eventually making holes on the floor board.
- What size and type of screws should I use?
Does anyone have any other ways of getting the heat shield onto the underside?