Body Rust Survey and Remediation

[rvsprinterguy]

Hi Everybody,

My 2004 Sprinter-based Class B is rusting around the bottom of the windshield and on the roof where the panels are welded together. Since I've had it, I've not appreciated the paint quality. From a body longevity standpoint, I get the impression that MB expected their vans to wear out before they rusted out. Well, mine's still running strong and I'd like to keep it from rusting out.

Since this is a California domiciled vehicle, I don't think there's rust affecting the structural integrity (definitely none I can see if I look underneath).

Has anyone taken their van to a paint shop and paid to have the rust arrested? Have you had your van completely repainted?

[mkguitar]

when I was shopping the rust on sprinters was a concern I noticed - sprinters used as delivery vans etc often show rust.


rust on the top can occur when you live seaside and dirt is allowed to accumulate.


a wax coating and frequent hosing to remove the salt spray is required from new




I learned the hard way- lived sea-side and had a car roof rust off in 18 months- CDN laws required Renault to replace the vehicle




rust is cancer once it starts the metal needs to be cut out and new welded in, it is a tough battle. and around the windscreen will be intensive with the compound curves




mike

[rowiebowie]

If Interblog weighs in, she can illuminate you on windshield rust on the TN1 units. Yes, rust is a thing.

[booster]

"Rust never sleeps" has a lot of truth to it. It is hard to fix permanently in a classic vehicle that will never see harsh conditions again, so daily drivers usually don't hold up very well.


Other things going against the Sprinter is the location and the design type. Rust around windows most often entails cutting out and replacing somewhat complex bent up sheet metal shapes that are difficult to reproduce if not available in the aftermarket, and they have to fit very well to seal up windows without leaks. Add to that the fact that it is on a unibody, where nearly everything is structural, and it gets even more important to fix it correctly.


Rusty unibodies wind up with it in a lot of the seams and flanges lap joints where you can't get at it without cutting it all apart, so get limited to either using oil/wax penetrants in hidden areas or trying to encapsulate it in on the visible edges with epoxy or undercoatings.


I have seen classic bodies, stripped down to just the body steel, sent out to derust in an etching tank that go out looking not all that bad and come back looking like swiss cheese from all the hidden corrosion.

[rowiebowie]

Originally Posted by booster

"Rust never sleeps" has a lot of truth to it.

I have seen classic bodies, stripped down to just the body steel, sent out to derust in an etching tank that go out looking not all that bad and come back looking like swiss cheese from all the hidden corrosion.

Unfortunately true. Whatever you can see, there's always more that is unseen.

In a house analogy, years ago I used to watch "This Old House" and the Host would introduce Norm while he was checking on some visible wood rot on the back porch of some project house. He'd always say "We'll check in on you later Norm".

Later, the Host would check back and ask "Well Norm, what do you think?"

Inevitably, Norm says "This whole porch has to come off".

[rvsprinterguy]

Thanks for all the information. I'm probably going to go the strip and encapsulate route (with some kind of epoxy coating) around the windshield with the hope that I can keep the rust from getting worse there. Fortunately, it's still a small area. On the roof, I have one area of "bubbling" along a seam. I'll strip that area, too.

Has anyone had luck with Eternabond RoofSeal tape along those seams?

[booster]

Originally Posted by rvsprinterguy

Thanks for all the information. I'm probably going to go the strip and encapsulate route (with some kind of epoxy coating) around the windshield with the hope that I can keep the rust from getting worse there. Fortunately, it's still a small area. On the roof, I have one area of "bubbling" along a seam. I'll strip that area, too.

Has anyone had luck with Eternabond RoofSeal tape along those seams?

Bubbling paint is caused from underneath, so when you strip, you need to part particular attention to finding out where it came from. Seams can be very tough as it may have been water leaking a long distance away through a seam in seam sealer or could come from inside as condensation. Rust on a sheet metal overlap joint is very, very, hard to stop unless you break it open, but don't go there without lots of tools and experience. In a unibody, the seams almost all flex to some degree, so any hard sealer like epoxy may crack over time and use. The use of a paintable, flexible, seam sealer may be a much better option. It is what we used to see in the older cars at the corners of the trunk opening up to the rear window as that was a big flex point in those days. If you get regular autobody repair grade paint, most can be mixed with flex agent to prevent cracking and it would be appropriate in a case like this. Get a cheap airbrush to put it on a small area. Don't bother with base and clear for this, just go with a single stage urethane with harderner and flex, and to keep it more flexible you can even leave out the hardener if the paint allows it.

[GallenH]

Originally Posted by booster

I have seen classic bodies, stripped down to just the body steel, sent out to derust in an etching tank that go out looking not all that bad and come back looking like swiss cheese from all the hidden corrosion.

True. I did a frame up on an old vette. Had the frame and some suspension parts trucked to a nearby place where they placed them into a electrically stimulated chemical bath for 24 hours. Then hosed out extensively. Some areas of the X frame were severely rusted. It then got trucked to a guy who builds frames and cages for NASCAR racing. He cut out the bad parts, welded in new frame and welded the stitch welding so that it was continuous. Can't tell where he did his work after painting. Wouldn't survive show judging, though. Still has held up well in AZ.

[GeorgeRa]

Registering an older car in Germany suspected for a corrosion damage needs to pass a “screwdriver test”, it gets pocked from under the car and any penetration deems it unsuitable for registration.

[rowiebowie]

Originally Posted by GeorgeRa

Registering an older car in Germany suspected for a corrosion damage needs to pass a “screwdriver test”, it gets pocked from under the car and any penetration deems it unsuitable for registration.

Glad the doctors don't apply a similar test to me. At my age, I wouldn't pass either.

[booster]

Originally Posted by rowiebowie

Glad the doctors don't apply a similar test to me. At my age, I wouldn't pass either.

There are actually places that are worse than that, I think. When the more common then body on frame cars were around more, some jurisdictions went by "visible perforations", so a small hole at the the bottom of of a trunk quarterpanel would need to be repaired even if the important stuff was fine, like the frame.



That said, unibodies have made it much tougher, I think, for both the public and the regulators. When a rusty windshield frame is a structural element, as is the roof, the doors, etc., where are the lines drawn?


I have seen too many cars where the rear strut towers have busted right through the trunk floor to think that loose inspection is better, but I have also seen vehicles gigged for trivial stuff of no safety concern.

[mkguitar]

Originally Posted by booster

There are actually places that are worse than that, I think. When the more common then body on frame cars were around more, some jurisdictions went by "visible perforations", so a small hole at the the bottom of of a trunk quarterpanel would need to be repaired even if the important stuff was fine, like the frame..

I had a 1977 elcamino in Toronto.
In 1983 to pass inspection i covered the holes through the tailgate with a bumper sticker and the hole in the pass floor ( over the cat) with a piece of sheet steel



In 1984 the car went as a motor donor to a guy with a better body- just too many issues to pass inspection


Mike

[Leorahkp]

We have a 2005. Three years ago we noticed bubbling under the paint at the top right corner of the windshield. We took it to a reputable truck body shop. They told us that Sprinters are known to have this issue. Their recommendation was to cut out the rusted area with a good margin around it, remove the paint from the area, treat the metal with a rust preventative, prime, paint and clear seal it. They would not guarantee the repair, since on Sprinters their experience is that the rust will eventually return anywhere the base metal has been nicked or cut. So far, it still looks good.

[Scottie409]

even the service manual for a Spinter will rust!

[beyond.denis]

Originally Posted by rvsprinterguy

Hi Everybody,

My 2004 Sprinter-based Class B is rusting around the bottom of the windshield and on the roof where the panels are welded together. Since I've had it, I've not appreciated the paint quality. From a body longevity standpoint, I get the impression that MB expected their vans to wear out before they rusted out. Well, mine's still running strong and I'd like to keep it from rusting out.

Since this is a California domiciled vehicle, I don't think there's rust affecting the structural integrity (definitely none I can see if I look underneath).

Has anyone taken their van to a paint shop and paid to have the rust arrested? Have you had your van completely repainted?

I have a 2006 Roadtreck adventurous with the same problem. I had a cracked windshield which needed replacement. Because of rust I had to replace the bulkhead. The body shop was able to cut out the lower part of the windshield frame and weld in a new cowl replacement. It was less than expected. $1600. vs $2800. to repair the framing all around. It should last for the life of a vehicle. There is a replacement part for just the cowl. Be sure to check around and get estimates. Good luck.

[rvsprinterguy]

"I have a 2006 Roadtreck adventurous with the same problem. I had a cracked windshield which needed replacement.."

The start of my rust problems around the windshield was replacement of a cracked one. I think the shop badly scraped the paint with their sawzall when they removed the old glass.

I like the idea of having the bottom of the cowl replaced. I'll look into that.

[booster]

Originally Posted by rvsprinterguy

"I have a 2006 Roadtreck adventurous with the same problem. I had a cracked windshield which needed replacement.."

The start of my rust problems around the windshield was replacement of a cracked one. I think the shop badly scraped the paint with their sawzall when they removed the old glass.

I like the idea of having the bottom of the cowl replaced. I'll look into that.

A sawzall to remove a windshield? I have never, ever, seen that.