Which is the most frequently failed ';sheet-metal'; part in the car?

Do you mean rusting through? Front and rear fenders right behind the wheels.





These areas tend to hold moist salty dirt from the road and receive a constant sandblasting from the wheels.





The same for the bottoms of doors and tailgates, the drain holes get clogged and moisture stays in there and works 24/7 rusting the metal.





Rear bumper covers tend to hold dirt and salt in them and rust the metal underneath.Which is the most frequently failed ';sheet-metal'; part in the car?
You'll have to be much more specific as to area and what you mean by a failure. If you're talking about rust floorboards, cab corners, wheel wells, and any other place where gunk sprays up and can't easily get out of.Which is the most frequently failed ';sheet-metal'; part in the car?
i would say the floor board because it gets the most water from your shoes. water on the outside can run off but the floor, it stays there.
That darn heat shield on the exhaust (iff that counts)

sell makeup