Just noticed this rust spot on my 2005 F150 SC and not sure if this is a common problem at this spot or if it’s from when I had a dent fixed on the door and they had to re-spray the entire door and the corner of the cap and they didn’t prep right, it’s on the driver’s side lower back corner of the cab right in front of the bed

 

Very common with these trucks...something about the door leaking up top and water dripping all the way down and settling in the corner like that.

 

yep i have it there on both sides

 

I'm going to bedline under my rug to prevent damage

 

I have that on my passenger side.