I have an '07 unlimited and my tank skid is rusting from the inside out. I do preserve/paint my entire undercarriage every year or two since I bought it in 2010. At that time it had been in CT since it was leased by another owner and the salt had not been kind to the undercarriage. It took me three days to preserve the undercarriage and my stock rock rails back then. I never dropped the gas tank skid back then, but I did take the outside of it down to bare metal before priming and painting.
So fast forward a few years, I actually got stuck on a rock about 2 years ago in Uwharrie when I pre-ran it with Mr. Ty. I had to use a lot of power (rear locker engaged while in 4 wheel low) to get over it...it felt like I was high ended until I got free. I was very close to getting out and using my winch. After I got off of the trail I noticed what had happened. I had a 3-inch ovalish hole in my skid plate just before where the gas tank portion of the skid starts. So I start pressing around it and portions of the steel/rust (with a layer of wet muddy sludge) chunked out in places. So I grabbed a flat head screw driver and tested the entire skid. Luckily for me the ski plate was only compromised in this section. So I used the screw driver to remove the failed section and opened the hole up to about 4 inches. I cleaned out the remaining crud sitting on top and painted everything I could. I didn't weld on a new plate because I figured I would just replace the entire skid because I'm sure it will fail for the same reasons in other locations within the next couple of years.
Frankly I don't see any drainage areas for mud and crud to be washed out, so I'm pretty sure it just sits in there and corrodes the metal on the inside of the skid. I don't see anything else to do about it unless holes are drilled into the skid, which I won't do unless it is removed and the gas tank taken out. So I'm a few years, I plan to get a spare/used gas tank skid, modify and pressure it and then replace my current one.
'07 JKUR ... mod'ing never stops...
