Hey, new to the site but a long time reader and Ford owner, my 2005 F150 Crew I bought new in 05 has the same issue, bought the cab corners in the Spring just took a look at it and it has spread down the rockers, Sucks, fortunately I am a long time body guy (hobby/side business) I do have a sunroof and I took some water and poured around the sunroof and I bet you can guess where the water poured out, yep you guessed back rocker where the rot is and all along the rocker seem, what a Stupid Idea. Can't Ford at least take a couple tips from the Germans and run the tubing outside and not in the rockers. I am pissed as this started rusting just after the 5 year warranty. Oh well, I will see how I can improve their fault and never buy another Crew with a Sunroof!! thanks for listening to me bitch!!

 

No sunroof here and had the same issue. I think it's more about the corners acting as scoops for all the crap comin off of the front tires.

 

Is this only happening in areas where road salt is used for snow or ice? I'm in South Florida where we get about 6 ft of rain a year and have yet to see any corrosion on these trucks except for the electrolysis on the aluminum hood.

 

So I'm I correct in my thinking that this rust comes from the inside and by the time you see evidence on the outside not much can be done except cut out the corners and replace? I am starting to see the bubble. I was going to have the corners blasted and then repaint but I am starting to think if I even start trying to work with the metal that is there I am going to make large holes in each corner.

 

By the looks of it my passenger side will bust through in the next couple of months/year, the drivers side is spotless though, I took it to 2 body shops and they both said they don't do "rust repair". Heck was was even call a "restoration shop" So I don't know where I can take it, one shop told me it was the 3rd brake light but I took it off and it was dry as a bone, even had dust under it, so no water through there. I think it comes up underneath like Especial86 said.

 

Sorry no pics to put up of before but I will take some of the after. Nonetheless they were both very bad with the rust creeping around the corner into the door sill area.

Both fix now, along with a repainted box (paint flaking under the stock FX4 flares) and new camo FX4 decals

I will be going with bigger mud flaps on the front (still have the factory solid ones on the front) and I am thinking of some kind of flap under the rocker are to keep crap from getting up to the area directly.

 

I took my car to 3 body shops and all three did repair estimates. Was for rocker panel replacement. The lowest price shop did an excellent repair.

 

I have to get mine done in the spring. Told the guy at the shop about dust under the 3rd brake light. he said if there is dust that water can also get in. I asked him about the sunroof drains he told me they go through the A-pillars.
After mine is fixed going to get it hot oil treated.

 

Okay, I have looked a little deeper and have confirmed that the rear sunroof drains dumps inside the C Pillar in the cab corners. See attached. Contacted Ford Customer Care and obviously due to the year (2005) they would not look at it or do anything as I suspected. So purchased cab corners and new rockers and will replace in next week or so. Front rockers appear okay as I have checked inside by pulling plugs out under truck.

 

Where did you purchase the cab corners? I can only find them at one site.