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I'm massively pumped. Car is now sound and rust free and ready to go on for years. I don't know if I was a fool, a madman, or some kind of a hero to do what I did but I'll describe it. Repair was mainly with automobile sheet metal and 3M Body Panel Adhesive 8115, plus lots of pop rivets along the seams.
The car, a '96 with now 177,000 miles, looked fine but I knew it wouldn't take a sticker because of rust holes in the inner walls of the rear quarter panels, behind rear wheels. It was actually far worse than what I thought, I found when I got into it.
This was an ongoing thing, dating to a year and a half ago when I bought the car, but basically since June when I buckled down to it, then let it slide a couple months. Then the last three weeks as often as I could get around to it.
I pulled the rear rubberized PVC trim skirts, that bolt up to body and tuck into rear bumper, and also the wheel arch trim. Then I began tapping around and revealing true extent of things:
A palm-sized hole in rear of LH rear wheel well, that started where a blue plastic grommet for mounting bolt was pushed in. Also a pretty major hole up at front bottom of wheel well, and out onto bottom of car. And the bottom rear of the wheel well up quite a ways and wrapping around and extending the length of the inner side of rear quarter panel at bottom. A big hole up into trunk floor at LH side, near where CD changer is mounted. Some holes rusted into the bottom and sides of a boxed sort of frame member, right at the back near where the bumper mounts. Various patches of serious but not perforated surface rust, mostly at places along bottom edge of wheel well on inner side. A 3" circle of deep surface rust on the rear of car below hatch, under and hidden by the bumper. Rust at each of the nylon grommets that the wheel well trim pushes into, so grommets pulled out of car with trim, and two of them, badly eaten away, missing 1 1/2" of arch at one, 3" of arch at the other, once it was all knocked and ground away, with rust just starting up onto paint past the trim, and into interior wheel well quite a ways, and a gap into interior between two panel lips.
RH side similar but not as bad, mainly inside of rear quarter panel, near full length, and up 5" of wheel well out to near wheel well lip. Also at rear end of boxed frame section as other side, and at back bottom middle of wheel well where another blue plastic grommet was pushed in, so thin it needed a patch. Several surface patches at bottom of inner edge and up under car on underside, out around where brake hose attaching bracket sits for instance, and at forward bottom edge of wheel well and out forward under car a little to near where ABS brake line enters bodywork.
This is all caused by typical New England winter weather, weeks on end where cars carry around chunks of brown salt slush adhering to the underbody especially ahead of and behind wheels. The salt brine eventually finds its way through the undercoating and starts working away under there, where the undercoating keeps it moist - - doing its job in reverse sort of.
There is absolutely no rust up near the shock mounts, which most people call a car killer. If a car has rust there it probably has far worse rust down where I found mine I'd say.
Besides knocking with a hammer, which breaks open the outright holes and nicely clears lots of the worst rust, I did much digging and scraping away of the painted grey rubberized undercoating and whitish seam sealer with various wood chisels, used the wrong way so they dig down to the metal and then slide along it. You need to find the edges of all the rust and then go a good ways out beyond that to get to good metal.
First of all I cleaned the whole area well with a bucket of water and a rag, wiping repeatedly so all sand and mud was off so it wouldn't be fallig in my eyes.
You can usually see where it's bad, undercoating slightly bulging and looking and feeling puffy, or with traces of rust stain on the surface. Tapping or scraping breaks this off and reveals the rust.
I scraped and tapped away what I could, then went to work first with a cutoff wheel on an angle die grinder, skating it around at low speed, then with a cone-shaped stone tip on a Dremel tool, or just plain scraped with screwdrivers or even the wood chisels (shudder) to get frank rust off, and the fewest dark pits remaining possible. Rusted-away stuff either fell out or I had to use cutoff wheel, tin snips or the Dremel to get it off. Spot welds, I ground down to smooth with cutoff wheel or dremel wheel.
Then I treated it all with body shop rust conversion coating, like Ospho, that converts remaining iron oxide to something non-hygroscopic (water-sucking) and helps stop rerusting.
I made up cardboard patterns for sheet metal patches, out of old cereal boxes. Then I got some auto body sheet metal, a piece from a glass shop that installs aftermarket sunroofs, which they had cut out from a car. A good source for this stuff, to them it's clutter and they usually give it away to scrappies.
I cut the patches with Wiss aviation tin snips and it was blister-raising hard work. A thief stole my brand new unused DeWalt electric shears from an unlocked car last year, bummer. Filed rough edges smooth, then had to bend the panels to fit the car. Cardboard is supple and seems to fit nice; the stiff sheet metal takes several tries and some subtlety to get it bent right, especially if it has compound curves. A vise, hammer, pliers, vise grips and a crescent wrench all helped, plus a hammer to beat into final place once trial-fitted and riveted in a few places. The inner quarter panel pieces were long gerrymander things, and needed a couple diagonal bends, about 45 degrees, in quick succession about halfway back. Also, the panel has embossed cross ribs and one of those passes under an edge of my patches and I'll need to fill that in; I have some 3M urethane seam sealer in a foil-and-plastic tube like sausage meat, that I'll use to fill there. I opened that tube last year and folded its end and resealed it with one of those big black office binder clips and it's still soft inside so I think I can reuse that.
Then I used 3M Roloc Scotchbrite discs on angle die grinder to remove all the paint from edges of the patches, and the receiving edges of the body, so the panel bonding epoxy would stick.
I marked all along edges good places for pop rivets with a Sharpie, then drilled 1/8" holes with a cobalt drill bit all around. Held patches clamped into place with vise grips, drilled a few of the holes thru into the body, put temporary pop rivets in those holes to hold the work in place, and drilled all the remaining holes.
Then to the 8115 panel adhesive. It ain't cheap, $61 a tube to me, maybe half that to a pro since I discover they typically get about a 2/3 discount off list instead of the 1/3 I was offered. There's a lot there, but since I was coating not only the actual seams but up inside the holes, around onto back sides of the work where it had rusted, then entire back of patches, then, later once all glued and riveted into place, coating entire outside of work, up onto the good metal of the car and over onto the good undercoating around the hole, I used a lot, 2 1/2 tubes so far with a little touchup to go and more work at front wheel well lips to prevent future trouble there.
It's great, covers sins and fills pretty big gaps and sticks like iron, and it's impervious to water and I'm betting better than any undercoating the car ever had at stopping rerust.
The stuff calls for an official dispensing gun but I didn't want to pay for that; I made up a rig with a block of maple I had and two long 5/16" or 3/8" carriage bolts, sticking out of the block and centered to go down each of the tubes and push the pistons to dispense the stuff. If you do this you need to be careful to push straight so the proper proportions come out the nozzles. Two long dowels screwed to a board would also work.
Also, I skipped using the mixing tips 3M gives you as they hold and keep you from ever using a pretty good quantity of the glue each time you dispense. I dispensed onto the cover of a cottage cheese carton, my artist's palette, and mixed with a plastic rod I had, till it was all uniform. Be careful, as I said, to keep the amounts dispensed in the proper proportions, pushing the same amount square on each side, because if they're not close enough then the adhesive won't turn out right. One small batch I made didn't dry and I had to scrape it off. The larger the batch the less likely you are to get proportions off.
Then I spread it with 1" to 1 1/4" squares or rectangles of cereal box cardboard I had cut a lot of, with two pairs of nitrile gloves on each hand. Throw cardboard away if it gets floppy. Peel one pair of gloves off any time you need to touch anything you want to keep clean.
Paint thinner works pretty well to clean the stuff off before it has hardened. On your skin, soap and water to quickly follow. Soap, water and rubbing alone will get some of it off while it's still gummy. But it takes rubbing and maybe a day's wait before the body starts to molt old skin cells if it hardens on you.
I coated the area on the body where a patch was going, then laid out enough rivets and the rivet gun, then coated the back of the patch and, holding it by edges, put it in place and got a couple of rivets in. Then pressing it hard into place, put each of the rest of rivets in. Every 2" or a little closer. Then usallly after it was pretty well set and I had cleaned back up I mixed more and went over the outside, sealing seams that hadn't pushed up their own bead, and coating everything, including rivet heads and over onto good paint or undercoat. A final visit to catch little spots missed.
On the gaps on one arch, I could have left them and just filled the crack into the interior and over onto the sheet metal at each side,. But I cut a piece with like a long tab to stick into the crack into the interior, and "ears" over under the arch edge at each side, with holes to pop rivet it, and the main patch section I also extended and bent the lip down at 90 degrees about 1/8" inch similar to original body metal. Then the epoxy filled gaps and covered sins. I'll mark and drill through where the nylon grommets go and attach those with some more epoxy to seal the drilled metal edge, also will epoxy the other ones that pulled out of their holes back in.
I had to do quite a lot of scraping away old undercoat and seam sealer, especially at wheel arch edge, where rust had crept up under the seam sealer along on back side of arch edge. I used mainly a small crappy wood chisel. A cutoff wheel or even dremel stone chews thru the stuff pretty good too but not as precise.
So now what else is to threaten my car's body? I know of some rust below the hatch latch, on the sheet metal lip where the hatch gasket is pressed on, now hidden by the gasket. Will have to make 24 hours or so off road to deal with that. I also have to get at the jack points, at all of which the undercoat has separated from the lift point brackets and probably nearby body. I haven't ever used these points to jack a car since my early VW days when to do so ruined a body instantly. I just find a good solid point under the suspension, on 9000s usually the center of rear or center of front or under each A-arm or the corners of the front subframe, or out at ends of rear axle. But it might take much of a tube of the 3m epoxy to cover them all.
The condition of the sheet metal below my windshield is unknown and worries me; maybe some day I'll pull things off and see if that needs rust treatment too.
Also, I have a can of Hammerite Waxoyl undercoating, and may apply that to all the work I did, and to any areas I suspect of being under rust assault.
I know a lot of people on here are big fans of POR15, but I can never quite get over its "paint over rust" ethos. Rust is NOT something to be trusted, even painted over with an all-solids thing like a cyanoacrylate paint that is quite moisture impervious. I've seen POR15 peel clean off bare metal in a sheet once dried; it tells you to anchor it to rust for a reason. But the rust left behind will try to pull water out of the air and keep rusting, and if it succeeds it has the POR15 over it to keep it from drying out and let it keep rusting. My thinking is, the 3M stuff I used is also moisture impervious, and bonds like crazy to bare steel and pretty well to most other surfaces. The car is otherwise sound and I want to keep it and think this will work. Fingers crossed, time will tell.
Oh, I got my safety inspection sticker this morning, sailed right through.
posted by 71.173.65...
, Sat, 29 Sep 2012 07:43:40, Sat, 29 Sep 2012 15:32:01
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