herring

Now that is a proper repair. Looks great, and that's what I wish I could've done. I used to be a proficient stick welder, but my skills and eyesight have faded, so I chose an easier option and cut sheet metal to paste on top using JB Weld/Kwik-Weld. I posted my process in this thread. I'm just responding to point out that there are ways of dealing with the rust that don't require a welder or the skills to use one, just a grinder and the willingness/ability to shape sheet steel to fit. These cars are getting older now. I 100% agree that whatever rust you see, will be much more significant once you get into removing it. Be prepared to cut out and patch a lot.

Well, the title says it all--now I can only see through about half of my rearview mirror because the holder hangs down. Are there any clever fixes for this?

Get down on the ground, take some pictures, and post them. If you can, remove the rear wheel and pull out the plastic liner from the front part of the wheel well so you can look in there. Might be able to clean things out a bit at least. Fluid Film seems to be a good product for slowing rust. The real problem is when the rust spreads from the rocker panel to the structural metal behind it.

I believe what you're looking at there is a gap between the steel body panel and the plastic wheel well liner. You're right that dirt, moisture and especially salt can get behind it and start rust. Before you seal up that gap, I'd remove the plastic liner and clean out what's behind it already. You'll need to remove the wheel, and then pop out the plastic fasteners (one is seen in your picture, I forget how many there are). There's a specialized tool, or you can use a flat screwdriver. I'd argue it's probably better to do a remove-and-cleanout after each winter than to try to seal it. Also, that's not the only source of rust. Some people have it start there, but as you'll see from my photos in this thread, I had rust underneath but none behind this liner.

Chrysler products (including Jeeps) seem to rust most easily. Fords may be second-worst. It's true that the European and Japanese brands seem to be better about rustproofing their cars. But I think there's also an "owner bias"--my theory is that people who buy European and Japanese brands are on average more attentive owners (notice the rust early) and have more money to have it professionally repaired. European cars, especially in the US, tend to be owned by people who care about appearances. So rusty European cars get fixed or sent to the junkyard, while rusty Chrysler products keep chugging along until something major dies (or they can't pass a safety inspection). I realize there's some stereotyping here but I think there's truth to it.

I realized grinding wasn't going to get away all the rusted metal, and went to cutting it out. Kwik--Welded (JB Weld) some 22-gauge steel over the cut. 2 coats of primer, 2 coats of paint. Would have used regular JB weld for filling in the seams, because Kwik-Weld sets in a few minutes, so the fill at the edges is rough.

After starting to grind away...

I wanted to address the rust on my passenger side before winter came. When I started getting into it, it was worse than I thought. I had to go back and buy a larger piece of steel to make the patch. The pictures are: -when I used a flap disc to grind away the rusted areas -after cutting out the rusted areas -after patching. I used 22 gauge steel, held in place with Kwik-Weld (JB Weld's fast-stetting version). Unfortunately it was too fast-setting and I couldn't fill in the gaps properly, which is why the result looks a little rough. But my car is a 2010 and at this point has some other small cosmetic imperfections so I'm not going to worry about fill issues below the doors. I then filled in (using the holes I drilled) with lots of Fluid Film.

This is what I did. I found a can of Fluid Film at Home Depot and gave both sides a good amount. I had already squirted some oil in but this may spray better and so provide more coverage. Probably an easier solution for most people. Time will tell how well it works.

That tape-and-tube seems like a great solution. Easy enough to check periodically to be sure it hasn't come loose. I did notice some oil dribbling out of the seam as well--I thought it was a defect but it makes more sense that it's intentional. I had another thought, if someone didn't want to mess with a sprayer and oil, to use WD-40 and its straw. WD-40 is known more as a lubricant, but was actually invented to drive out moisture and prevent rust. I didn't investigate the fluid film but thought I'd mention WD-40 since it's easy to find and cheap. You might even be able to get enough coverage going up through the bottom hole, and skip drilling the holes above the rust.

4. Note that right above area of corrosion is a place where the seal on the door meets the door frame. A hole(s) drilled here will be covered by the seal when the door is closed. Drill a couple holes over the corrosion area. Plug up drain hole under rocker panel as best as possible with a rag/paper towel. Use an old weed sprayer and some used motor oil to inject oil into holes. (Note, put an oilpan underneath to catch what dribbles out, which I forgot to do. Otherwise, dig up oily dirt and throw in trash.) 5. When oil stops dribbling out, replace the air deflector. To do what I did, you'll need a bigger drill bit than comes with a regular set of bits. I used a 5/16, but it depends on what size head your sprayer has. In my case, I already had the drill bit, an old sprayer, and some used motor oil. But even if you went out and bought a sprayer, bit and quart of chainsaw bar oil (which is good for this purpose) you should be under $25. This is not a perfect solution, but it's easy and cheap, and based on my experience with other cars will slow down rust coming from inside. On the driver's side, I removed the air diverter and felt around inside the hole as best I could. It seemed dry and smooth. I removed the wheel well liner and checked for rust. Since those were clean and there was no sign of bubbling on the rocker panel, I decided not to do the drill and spray bit. But I will be keeping an eye on it. And I'll spray more oil into the holes on the passenger side each year. I am conflicted about what to do with the air diverters. Leaving them off will let salt get inside the rocker panel in winter, but leaving them on interferes with drainage once dirt accumulates. They should at least be cleaned out annually. On other cars I've seen drain holes fitted with rubber plugs that allow drainage but not water/salt to go up inside. This is definitely a design issue.

So what I did was: Remove the "air deflector"--1 10mm bolt. Noted that it has a shallow "pocket" which was filled with damp dirt. Scrub that out. No obvious corrosion around the drain hole which it covered up (first pic). After jacking car up and removing wheel, pull off 3 trim clips and pull out liner near rocker panel. Clean out accumulated dirt, no sign of rust. (continued)

Hi, This is my first post on this forum. I have a 2010 Fusion SE and have lately noticed rust bubbles (i.e. rust coming out from the inside) in front of the passenger side rear wheel (pic attached). Driver's side does not have this issue. So it looks like I need to remove the plastic 'air diverter' to get access inside? I'm not an auto body expert but have a 40-year-old antique and have had good luck with that by spraying oil (particularly chainsaw bar oil) inside body panels. Are there any specific directions for removing the rear wheel well liner for 2010-2012 Fusions?