Just fiberglass that also... J/K

Cut the rust out and fix it right if you plan on keeping it long. I did mine and it will probably outlast the rest of the truck.

OUCH. just got a better look at the picture. That's a whole lotta ugly right there.
I don't think I would put much money into that, just run it till it drops.

Now that might be a good candidate for a fiberglass rocker repair job, something you only plan on getting a couple of years out of.

 

I don't mean to hijack the thread, but how does one go about preventing rust from getting that bad? I bought my '99 F150 about a month ago, but I found out that for the first few years of its life it lived in Ohio. The underneath has surface rust in several areas but nothing rusted through. Should I have someone pressure wash the loose rust dust off then spray some undercoating or something?

 

POR15 Good stuff.

http://www.por15.com/POR-15/productinfo/1GB/

 

Thanks!