I have 20 and 16 year old GM vehicles with blown out rockers and fenders, rusted away accelerated by the Michigan weather and salty roads. I am trying an experiment on the newest least rusty vehicle I own, a 2013 Cruze. I used Herculiner for the critical areas prone to rock chips and where plastic covers touch painted surfaces (that rub paint, harbor rocks and salty mix).
For all other underbody areas and wheelhouses that I did not Herculiner, I coated with Fluid Film rust protection. There are a lot of removable plastic plugs in the rockers, so this makes it very easy to coat the inside of the Rockers with Fluid Film, this will complete the rocker protection. I plan to re-apply the Fluid Film rust preventative before winters annually, in the areas prone to washing off.
Tools / Supplies
http://i.imgur.com/gFN5PbN.jpg
- 1 qt Herculiner
- Nitrile Gloves, I wore long sleeves and safety glasses too
- Blue painters tape
- Green scotchbrite pads
- Xylene
- Regular bristle brush
- Razor / knife
- Plastic push type clip removal tool
- Torx driver
- Fluid film (I got the 1-gal kit)
Pull wheelhouse plastic covers, lots of plastic push type clips and some torx head screws. After removal of all retainers, they covers come out easily. Tape it off, if you're a messy person or impatient, you should really consider extending the protection of your body panels from splashes.
http://i.imgur.com/f4A5ycd.jpg
First coat, shows critical rocker area I have covered. Rock chips leads to rust, stop the rock chips, stop the rust is my logic here
http://i.imgur.com/0kJp6WI.jpg
After second coat, tape pulled. I had to use Xylene to touch up areas where the herculiner go under creases in the tape
http://i.imgur.com/pdYu7Z7.jpg
Rocker Focused coverage (cover pinch weld and some buffer)
http://i.imgur.com/uZXCdQa.jpg
Critical area front, the plastic cover is a double-edge sword where abrasive contaminants like rocks, dirt and salty slurry get between the plastic and body paint, then rub away until bare metal, then rust.
http://i.imgur.com/XV3Bd0Z.jpg
Critical area fender lips front and rear, the plastic cover is again a double-edged sword, the plastic + contaminents will wear away the paint and rust like always here. Also note I covered a 5" or 125mm diameter circle around all studs that hold the plastic in:
http://i.imgur.com/5uja7zw.jpg
Plastic installed, inside fender lip
http://i.imgur.com/WwduIPL.jpg
Critical area rear, again, more double-edged sword
http://i.imgur.com/lJUtjee.jpg
Front of rear wheelhouse
http://i.imgur.com/pU0AcQi.jpg
Completed 1
http://i.imgur.com/gy4CSRF.jpg
Completed 2
http://i.imgur.com/wZpBV77.jpg
Completed 3
http://i.imgur.com/tnE9IkV.jpg
Edit: add detail + images