Stupid rust...

Ok...I found my first rusted out spot on my jeep. 94 XJ 2-door. The spot is right above the muffler. Its a fairly big spot, and its all the way through in the middle of the area. Here is my question, and Im sure its been asked. How much of a pain is this going to be? I can weld, and I have done some panel replacment before. Just not on a unibody in that area. First I need to find some replacment floor pans...junk yard? aftermarket? let me know whats out there. Second, once I start clearing away all the cancer, am I going to end up cutting out my whole floor? Im also not afraid to make my own panels... Please let me know what you guys have done. Im open for anything. Thanks in advance.

Justin

Having done body work for years, here is how I would fix it if it were mine. I would pull up the carpet, and degrease the area of rust on both sides. I would then coat the whole area with POR-15. That takes care of the rust problem. Now the task is to seal the hole. Once dry, I would take some duct tape and cover the hole from the bottom. Then using some fiberglass resin and cloth I would cover the whole floor pan area on that side of the back seat. If the heat from the exhaust seems like it might be too warm for the fiberglass directly, I would get a small air bake cookie sheet and attach it to the underside of the floor board above the exhaust. Lots of people do this just to keep the floor in the back from getting so hot in the summer. RTV can be used to attach the sheet. Most RTV's are good to 400 degrees and some high temp stuff is good past 600 degrees. If the floor ever gets to 400 degrees, the carpet will be smoking.

I recently noticed that I have the same problem on my 94 but I have yet to do anything about it. I am interested in this fiberglass resin idea but how big of a hole can that fix?

I've done it all sorts of ways over the years, but for floors I've found the most economical and longest lasting way is to cut the bad rust out so it forms a fairly neat hole with smooth edges, and screw a patch over the hole. For curved sections, the patch can be beaten into shape well enough. For this kind of repair, old metal shower stalls make ideal material, well worth hunting down. Check your local plumbing contractor's back yard. I use the little hex-head sheet metal screws with a self-drilling tip, and seal the whole business with brushable roofing tar.

I've never had good luck with fiberglass on rusty floors because it tends to delaminate. Pop rivets rot out and usually leak. Welding is fine, but you can eat up more man-hours replacing a floor than the vehicle is worth, and a year and a half later there will be new holes next to the new metal.

I like the idea of a cookie sheet as an insulator, though.

I like the air-bake cookie sheet idea, but why not clean the area under, rivet or screw the cookie sheet under it with it lathered in resin, the fill the hole from above and add cloth. That way you make a fiberglas sandwich for adhesion, it fills the area plus plenty to spare for future rot, and you get the insulator...

Just putting it all togetherarty:

Hmm...the fiberglass is actually a really good idea. I hadnt thought of that. The little bit of body work I have done usually required patch panels, so I was leaning towards getting a new floor pan. But...I have fiberglass mat and resin already. I was planning on insulating the floor above the muffler better after I fix the hole.
The jeep is worth it to fix it so that it will hold up, so Ill figure something out. I guess if the fiberglass doesnt work out, I can always cut around that and weld in metal. Ive never worked with glass before so who knows. My biggest fear is pulling up the carpet, and finding endless rust once Im under there. I have to get my hands on some POR-15.
Hey...atleast now I know why my jack was so darn hot when I went to use it the one day. Almost burnt my hand. And here I thought the paint was flaking off and I was looking at bare metal...or the bottom of my carpet.

Justin

I have two questions before I decide on a course of action. First of all...Im still thinking about trying the fiberglass idea. chryslerpartsdirect.com has a floor pan listed for like $190. The pic seems to be only the rear portion of the floor...and might not even get to the area I need. Does anyone know what is included with this floor pan? How far does it cover?
Next question...where is the best place to get my hands on some por-15. Never used it before. Is it brush on, spray on? Let me know so I can fix her bottom. thanks.

Justin

It's SCARY how I find my problems here on the forum first!! I just looked at mine and theres a rust hole over the cat.

I think I'll clean it up and use "The Must for Rust" which is a phosphoric acid conversion available at Home Depot and works really well (use it on my trailers), then make a fiberglas sandwhich with that double cookie sheet. It should cover the whole cat area, it's aluminum, and it'll have to rust out to 2 ft by 2 ft to fall out.

I was at a restaurant supply today and saw the various sizes of professional baking sheets in heavy gauge aluminum. I may use 2 of those instead for a heavy duty fix instead.

My local auto body supply store stocks POR-15. The stuff is scarry. Once it hardens, it is damn near indestructable. Sanding it off takes a lot of work. You can also order it online as several places as well as www.por15.com. It is simply the best paint for axles and underbody, or anywhere you find rust that there is. It stablilizes the rust, period.