It's held on by screws or bolts underneath and the heat shield corrodes and breaks around them. What I did to hold mine up is put large washers on the screws, or in the places that that will not work, I drilled holes in the shield and held it up with wire. Heat shields are terrible trying to keep on in New York.

 

Many people tear the heat shielding off.

The problem is bimetallic corrosion between the aluminum and the steel nuts used to hold the shields on. The nuts are originally coated with sacrificial zinc. When the zinc is gone the aluminum heat shield in contact with the nut vanishes.

Here's what I've done. I very carefully remove the retaining nut (24mm 6-point socket IIRC), clean it, and spray it with cold-galvanizing compound (Rust-o-leum brand). Bake it at 400F in an oven if possible. I fabricate roughly inch-and-a-half aluminum squares from 1mm-thick sheet aluminum stock (avaliable at your local hardware store), punch a 3/16" hole in them and use them under the nut to hold the shield where the now missing shield is. The thicker (1mm) aluminum takes longer to rot away.

Steel washers, even stainless steel washers will shortly just make a still bigger hole in the heat shield. It has to be aluminum. The cold galvanizing compound is almost pure zinc.

Good luck.

 

Steel washers, even stainless steel washers will shortly just make a still bigger hole in the heat shield. It has to be aluminum. The cold galvanizing compound is almost pure zinc.

^^ This

It's been a while since I did it and I forget that I actually in the end cut out pieces of aluminum roofing materiel because the washers were too small. As said above, it was a good thing I changed what I used.

 

Ok, thanks for the info...i'll see what i can do.Sounds like removing not a good idea.

 

When I did mine, Ford didn't have the "proper" nuts (it was still new to me then) - went to the local hdwe. store - stamped "top hat" nuts that fit the studs welded into the body were in stock, and dirt cheap. large washers 7 those nuts hav eheld it for a coupl years here in Buffalo.

And yeah - Dekalb is familiar to me, Lived in Watertown, Massena, Canton.... in the past...

Gods Country up there as we always used to say...

 

Is there a lay out of the underside of the car?

I have an 07 and i think i may have this down. Can i just drill holes threw the floor and then use self tapping screws to screw the aluminum up into the underside of the car? Then maybe spray some undercoating over the screw so it doesnt rust.