96 SE, so no frills XJ. I started stripping out the interior and got to the headliner today. I was under the impression that the base material was fiberglass for all XJ's, but given mine is an SE with no headliner speakers or rear light mine is a formed fiber board and very flimsey. The PO put in new headliner material that is already sagging and a pattern of feathers. Not my style so decided to redo it correctly, but I'm not feeling good about that flimsey backing. Any ideas? I guess I could source a fiberglass one or maybe try to reinforce the one I have. I'm not going to get to it until next week, but I'm afraid getting his material off could be a problem when glued to fiberboard. I also found the only rust so far on the XJ in the upper right corner under the headliner. It's not good, but not rusted through either so I need to figure out how to treat/fix that before the new headliner goes back up. I sure don't want to replace a section up there, but will do what's necessary.

 

They are all made from flimsy fiberboard.
You can reinforce it with fiberglass, but adding weight will probably bring other problems.
I've only fiber glassed broken sections.

As to the rust we can't help you until we know by pictures what you are working against.

 

How bizzare! So many posts and utubes refer to it as fiberglass. I can deal with it and reinforce it, but just another XJ hidden OEM price reduction. Thats what you get at this price point I guess. I can also deal with the rust. After a second look at the rust, after a fabulous Thanksgiving dinner I might add, it is definetly fixable without much drama, so I'll carry on. Still can't believe the headliner backer is so lame, but after owning 3 Jeeps since 1984 nothing surprises me.

 

For the rust, sand it down to the metal and paint it with POR-15. POR is extremely flammable and sticks to everything. Don't get it on you and wear gloves. It's also expensive.
Good luck and send pics with the progress.

 

My 89 MJ looked more like compressed fiberglass insulation with a hint of resin and a thin layer of crumbling foam. While you've got it all down, consider adding some insulation to the roof. I was having problems with condensation causing wetspots on the liner after I redid mine, I think it was because I wire brushed all the crumbling foam off. That was letting warm air from inside get through the headliner and condense on the cold metal roof. There are plenty of options, but I used this on the roof after I dealt with the rust. Fair warning, the adhesive is really strong. If you touch it with your fingers and you'll rip the material before you get it unstuck off your fingers.

 

You shouldnt need POR15 for the roof if its prepped properly. Sand it good to get all the rust off, grab the self etching primer, then paint. If you do use POR15, cover EVERYTHING. Seats, trim, all of it. Wear safety goggles, gloves, maybe a skullcap, and wear old clothes because that stuff doesnt come out. Dont get any on the lip of the can and put the lid back on, because once it cures, its sealed forever.

 

X2 on the gloves, and remember to take them off when nature calls.

Wow, has it really been 21 years since the original "How do I get herculiner off my hootus" thread? I feel old

 

My Triumph had a cardboard transmission tunnel hump, but they did it right as they added a layer of plastic bag material on the underside to keep water splash off of it. Of course the Triumph also had cardboard fenderwell splash shields. A paper car!