I carry a *lot* of stuff up there - including a large rooftop box.
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Post-having the front end overhauled - for which I had to remove all that junk so the vehicle would go high enough on the lift without hitting the ceiling - I got to take close look at the attachment points while replacing the roof racks
Right side doesn't seem to show any signs of rust, but two of the left side's attachment points show what I'd call significant rust.
Sure would spoil a day to go head-to-head with some 18-wheeler and have the gust lift the whole enchilada off.
Looks bad to me, but what do I know?
Pix:
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My kneejerk reaction was to unscrew the Torx bolts holding the roof rack anchor points in place, remove the whole thing, scrape away the bubbled paint, slather everything with rust converter, let it dry, and then re-assemble using Never-Seize on the bolts and/or maybe even replacing them with stainless steel bolts if I can find same.
But when I tried loosening one of the Torx screws, it was scary-tight - as in maybe the bold would shear.
I wouldn't be averse to taking the whole rack system off and drilling/bolting some aftermarket system through the roof - but I don't know what I'm doing.
Anybody been here? What's my fallback position if a bolt shears?
How about the prognosis for progression of the rust?
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I don't know how they do it on modern vehicles, but in the days of station wagon roof carriers.... They used a cheap wellnut setup. It was a rubber grommet with a metal threaded insert. The screw would cause the rubber to swell and this tightened against the sheet metal of the roof panel. I'm sure that you'll find a similar gizmo under yours. I don't think the screws go into a structure under the roof panel. This will be one of those times that if you start this project, you'll have to finish it, no matter what you run into. In other words, the roof panel may have enough rust that once you mess with it, maybe the hole will become enlarged and you might have a major repair coming. If it ain't loose or leaking, I'd say leave it alone.
I removed one corner on my 95. The torx bolts are tight, from rust. Some PB blaster loosend it up, but was still a PIA. Needed to work the bolt out. The nuts appear to be a PEM style nut, they didnt fall in, and looked as if they were embedded inthe roof.
The nuts the torx screws bolt into are called rivnuts.
Drill the torx bolt head off with a 3/16" drill bit, being careful not to damage the rack.
Grind the head of the rivnut off, under the nuthead is where the rust started.
Grind the rust off, within the confined area of the rack mount, use a good spray can primer. After you tape the area sized like the rack mount. Then let it dry well, and spray clear over the primer. Primer is very porous.
Let that dry, then buy nut seatable type rivnuts, so you wont have to buy the tool.
Remount rack, and it will be good for another 8 years.
I personally do this as a living, so I do the whole roof.
What usually happens is the rack is left a bit rough. Then with the movement of the roof through vibration those rough spots wear through the paint. Then it starts to rust. Same problem you see with the wheel arch moldings and many other add ons. They all move some and eventually wear through the paint. I'm betting that one side has more weight on it as well.
More than likely, there is a bit of rust at every rivnut.
Now that they are available in the bolt set bit, rather than the really hard ones, that you'll need the gun for.
I'm sure you can do fine, just make sure of one thing, if you have to grind beyond the base area of the rack, you can tape a shape of the base a bit larger.
Even up two inches bigger, and use the blue 3m fine line masming tape. So you won't have such a high edge.
Then use the 3M 411 Plus green tape for all the other masking. A few dollars saved on cheap masking products, can cause the need for repainting the whole roof.
Here's what I found in the one the looked the most egregious on the outside:
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The Torx bolts came out fairly easily, and I figured I was on a roll. "Lets take all these babies off and see what's under there."
Went up to the next station - no rust at all apparent.
Oops! Promptly buggered the Torx receptacles. Maybe #25 Torx was close... but not close enough?
Anyhow, that's it for now.... until I have the time/determination to do something more drastic to get the frozen and/or buggered bolts loose and deal with the expected repetitions.
I'm guessing with the buggered ones, it would involve peeling back the headliner and attacking the rivnuts from the bottom.
On the successfully-removed rear station, I scraped away the bubbles, slathered the area and rivnuts with rust converter, then re-assembled with liberal amounts of Never-Seize on the bolts.
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My guess is that there's more corrosion going on under all of the stations. The rivenuts look to me like one of those things that's just a bad idea..... Trannie valve bodies.... Intake manifold gaskets.... now these things. Thanks again GM!
Got about 160k on the vehicle now.... Just spent well over a grand having the front end moving parts replaced (drives like new now...) Was going to go for 250, but now I guess I need to watch and wait. Maybe that SprinterVan I've been fantasizing about is closer than I had thought.
In a way, I'm glad I didn't know what was under there on day 1 when I bought the vehicle new - or I would have been fretting about it not being robust enough. OTOH, I guess the more weight is up there, the harder it is for a gust to lift everything hard enough to pull something loose.
Looked at a 2007 'Burb today and they've cut back the bolts from two per station on the intermediate stations to one. Maybe they did something more robust underneath... but the cynic in me said "Gee, they must've saved a whole 47 cents on that one."
In case of the expected "yes", I guess it's take everything off, sand smooth, feathering into the surrounding good paint, prime, and paint with proper enamel?
I'm a little surprised I didn't see rust propagating from around the rivnuts. I guess I just got lucky with the rust nearby - or did somebody say something about vibration and the load working on the paint's adhesion?
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