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Interior roof rust


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Starting a headliner project ive discovered a leak has possibly developed somewhere along the front or rear windshield allowing water to seep into the roof support structure and sit forming rust. It almost seems as if the foam used to seal up certain parts is letting water travel through it. It may not be leaking though and is actually condensation forming on the roof metal, residue points to that and Ive had a pinpoint coolant leak in the dash someplace because it often smells like coolant but I cannot find where its coming from. Either way rust has formed in a place not accessible without cutting and re-welding but the metal is not compromised just yet, just bad surface rust. Ive thought of a few ways of going about fixing this but just wondering what some of ya`ll would do about the rust.


Some of my ideas were...

To get a bunch of silicone and pump enough into various spots to completely fill the voids. Or I think I can get an aerosol can of primer, rubberized undercoating or rust remover into some parts but I`d really need a WD-40 like stem to get at it good.


What I have done...

Completely removed about 80% of interior trim including headliner. Determined the majority of the rust is towards the front but the length of the center brace as well as the cross brace has spots all over the upper side were fluid can collect. It doesn't appear to be coming from the doors or side windows. In the meantime I have a can of a de-humidifier agent I found at Lowes I keep strapped to the back of the center console, made a almost a 1/3 of a bottle of water evaporate after a few hours so I know it will absorb any sort of moisture for now.

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Found it, upper passenger side windshield under the rubber reveal piece. Rust spot just above the urethane seal letting water seep through to the inside. Could`ve been my fault after working on the windshield in the past, could've been the shop I paid to fix my foul up. Whatever, its done, its here, going to deal with it, with some POR15. Inside and out and do some other stuff while the interior trim is out.


Will try and do this with some pics after the fact but the plan is to have someone help me pull the windshield out and spend a day fixing the bad spot of rust under the windshield, sand then primer black on the entire roof and windshield lip, then have them come back and lay a clean windshield on top of correct urethane adhesive. 


I did the trunk lid and wing not long ago and it looks a ton better, so it appears I`m giving up on the Aqua Metallic color and going a matte black until I can afford a decent paint job. Better than dents, rust and fading clear coat.

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  • 1 month later...

So this project has turned into a huge deal, much more than just fixing a leak. Basically its an interior resto at this point because everything has come out and will be worked on before going back in. The windshield didn't have to come completely out to get at what I needed to but some old urethane did, once that was cut out I took some 80 grit to the gap and took most the area down to bare metal before priming with 3 coats. Pushed a thin bead from the inside out then laid a thicker one down into the channel on top of it, then put on last bead on top of that and ran a flat object the length flattening the sealant out this morning. Several hours later the sealant is cured a bit and that windshield doenst budge now so I believe I was able to restore the structural integrity the windshield and sealant provide without having to pull the whole windshield. No pats on the back yet, going to give it a few days to fully cure and will break out the garden hose for a test.


Pics coming soon, got to show off the mess I made of this W-body. :showoff:

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It failed, wasted time, effort and money. Now the GTP leaks as well. Going to park both under some waterproof tarps and probably ride the bus for awhile until I have time to do the job right like I planned on the first time.


At least the roof looks better.

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Well instead of buying a phone I bought another tube of the 3m windshield urethane and sort of redid a few spots and worked a new layer smooth. It was a bit low in one spot and there was a small hole. This time though I had a heat gun heat up both the tube and the channel, this makes it really easy to flow and work flat. Got that done a few days ago and it seem to hold up.


It might snow good here tonight and if so I aint risking either car going to work and will have some free time for some pics. Its been a blast driving it around like this.

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  • 3 weeks later...

A few pics of how it looks today.

Plan is to do one section( of the 4 seating areas) at a time, Will pull up or disconnect the harnesses as needed to make way for the cleaning, and I`m going to roll on some insulating material to protect the metal. a lot of that brown you see isn't rust but the stuck on insulation panels that had the paint flaking off. I`m thinking a bedliner material or POR15 would be better than just black paint.



Welcome to the office, tossed the junk mail in the back nd that CRC actually went into the GTP.



The finished seal before the trim goes back on, after days of rain under a cover there was no moisture inside. Also painted the roof a flat black but because the car cover its all dirty ATM.




Building on the left in the trees is Autozone


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Some say its already started with one of the two cars usually there in some form of disassembly. Forgot to take a pic of the roof rust like the title of the thread, not much to see there though really.


Ironically as close as that AZ is, I work at the one further down the road that isn't nearly as busy or chaotic, lines in that AZ can be 20-30 people deep with only 3 employees in the store.


Hoping to finish up the rear bumper today and get it on and ,that will finish up that problem, then I can finish the door trim and seals and the one trim piece that used to be the windshield seal will go back on then I can get back to the inside work. I also worked out a few electrical issues. Still need to pull the dash out though.

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