roof seam rust repair

davisdave

2005 140 tall passenger
I have the rusty roof seams. Apparently they put the sealant on the joint and then paint it. Well, the paint cracks in the corner and begins to rot away. Another problem is the spot welds. There were some sharp burrs/corners on some and the paint failed...

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I used an oscillating tool with flexible scraper and removed the sealant...

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I used a razor blade, file, and scotchbrite pad to smooth out the remaining sealant and spot welds...

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davisdave

2005 140 tall passenger
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I then brush painted with Rustoleum Clean Metal Primer and then satin white enamel...

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Too bad Mercedes couldnt sand the joint down flush at the factory:thumbdown:

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Aqua Puttana

Poly - Thread Finder
2 other words.

Eternabond Tape

Clean the rust as best you can. Prime. Topcoat.

Then cover the entire seam with Eternabond Tape. White color. It comes in various widths. I prefer 2" or 3" width for repairs. The wider stuff can sometimes be more difficult to install.

Once my seams were covered with Eternabond my rusty seam problems were solved.

vic
 

Midwestdrifter

Engineer In Residence
2 other words.

Eternabond Tape

Clean the rust as best you can. Prime. Topcoat.

Then cover the entire seam with Eternabond Tape. White color. It comes in various widths. I prefer 2" or 3" width for repairs. The wider stuff can sometimes be more difficult to install.

Once my seams were covered with Eternabond my rusty seam problems were solved.

vic
Similar results here as well. As a rule of thumb you should remove the paint until you no longer find rust. Given the T1Ns crappy paint, the corrosion may have spread below the paint/primer for several inches beyond the seam.
 

Shibby!

Member
Thanks for the tips on the Eternabond.

I have to do this repair on one of my seams. Just starting to seep. For a temp fix I just sprayed it with fluid film to stop the corrosion issue.

Also need a oscillating tool. The results above are very good!
 

davisdave

2005 140 tall passenger
Yup, many approaches. This is a California truck...and it never rains here anymore:laughing: I actually have some Eternabond. Once i found that the raised ridge was sealant and would come off easily, i decided to just remove it and paint. I figure i can alway do the Eternabond later if the paint repair begins to fail.

I do not think my seam is compromised at all. If you look at the close ups of the seam after i smoothed it, you can see the darker orange on the rear side is the actual lap joint bondo seal and it looks perfect. I believe i just had surface rust ahead of the joint due to the spot welds and sharp corner of the raised sealant.:hmmm:
 

thesmith

New member
Just did roof seams on my '04 T1N. For my part i used a wire wheel to grind away the old paint and rust, used rust etching primer, new enamel, and a layer of 3M marine sealant over the entire seam on the inside. Used to leak, now it's dry as a bone.
 

Aqua Puttana

Poly - Thread Finder
Just did roof seams on my '04 T1N. For my part i used a wire wheel to grind away the old paint and rust, used rust etching primer, new enamel, and a layer of 3M marine sealant over the entire seam on the inside. Used to leak, now it's dry as a bone.
Not that you asked...

I'm certain that the sealant was effective. Keep an eye on the exterior surface though. Sealing the inside does nothing to prevent the exterior rust from returning.

Never underestimate how poorly the OEM Sprinter paint responds to spot rust repairs. That is especially true with the ubiquitous OEM Arctic Whitewash color.

vic
 

davisdave

2005 140 tall passenger
When i searched for posts about roof seam repairs, i dont think i saw any pics of a raised roof seal like mine:thinking: Could the flat seam be pre '05? Passenger vs Cargo?
 

Aqua Puttana

Poly - Thread Finder
When i searched for posts about roof seam repairs, i dont think i saw any pics of a raised roof seal like mine:thinking: Could the flat seam be pre '05? Passenger vs Cargo?
I just went out to double check.

Both my 2004 and 2006 have overlapped roof seams on the two joints that are over the back long window. Both of the OEM joints show the edge of the sheetmetal on the top sections. (Over the vertical edge down to the gutters is finished smooth.) Neither had any exterior sealant showing like is shown on the top section in the before picture of the first post in this thread.

Maybe someone already worked on that seam and added some sealant? Some of the self leveling sealants used on RV roofs have a similar appearance after curing.

My 2004 now has added sealant and Eternabond tape covering. While up looking I noticed my 2006 has a few problems. After I install the rear roof vent, the 2006 will get a similar treatment as I did to the 2004.

vic
 

davisdave

2005 140 tall passenger
I am pretty sure my seam sealant is factory. I got the van when it was 3 years old and the raised sealant was definitely painted same as roof. strange:shifty:
 

Midwestdrifter

Engineer In Residence
At some point mercedes started applying sealant differently to the roof seams. What is odd, is that it seems to be inconsistent, even within the same model year. I have seen photos of vans with almost no sealant at the lap joints. :idunno:
 

Shibby!

Member
At some point mercedes started applying sealant differently to the roof seams. What is odd, is that it seems to be inconsistent, even within the same model year. I have seen photos of vans with almost no sealant at the lap joints. :idunno:
After inspection that is what I found mine to have....
 
When we bought ours, you could see daylight from inside through the overlaps. Like no sealant. Luckily just a little rust. Sanded off as much rust as possible, primed/painted, eternabond on top. I didn't know about rust reformer/primer at that time. I'd use that first before primer and paint if I was to do it again.
 

Aqua Puttana

Poly - Thread Finder
I brush painted my 2004 with Gray Porch and Deck enamel. I used very little prep. The rust pocks which would previously reappear even after grinding, priming, and rattle can top coat have all been held at bay by the brushed on enamel.

Based upon that success, I just wire brushed my slightly rusted 2006 roof seams, spot primed, and top coated with brushed on enamel. After some cure time for the paint, I will cover the seams and repair with Eternabond tape. I'm not worried at all about the rust continuing to fester under the enamel and Eternabond seal.

vic

https://sprinter-source.com/forums/showthread.php?p=329061#post329061
 
I just ordered a 50ft roll of white 2" Eternabond tape from Amazon.

My previous fix using Rustmort, POR Patch (tube), and white Rust-Oleum paint lasted for a few years but is starting to show signs cracking.

Vic, I am planning to keep my cleaning and repainting of the seams as narrow as possible hopefully allowing the tape to stick on the original painted surfaces, instead of my coating... any thoughts on this?

Thanks, jim

Amazon has 1.5" Eternabond at half the price of the 2", but I figured that width would not be leaving enough on either side of the seam.
 
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Aqua Puttana

Poly - Thread Finder
...

Vic, I am planning to keep my cleaning and repainting of the seams as narrow as possible hopefully allowing the tape to stick on the original painted surfaces, instead of my coating... any thoughts on this?

Thanks, jim
Since you asked...

Based upon some of my rattle can rust repair failures, my feeling would be that you're better off getting out to good OEM paint unless you use something like Porch and Deck brush on paint. I believe that properly applied and cured brushed enamel will keep any future creeping of rust at bay. I have no data other than how well my poorly prepped repaired spots have lasted under my 2004 Porch and Deck paint.

Amazon has 1.5" Eternabond at half the price of the 2", but I figured that width would not be leaving enough on either side of the seam.
1 1/2" would be fine if applied as a preventative measure before too much rust formed, but I'd likely go with the 2" myself. A bit more bonding surface can only help.

vic
 

Gaspiper

Active member
Today I tackled the center seam that has been a leaker for some time now ! Grinded the rust inside and out with a Milwaukee wheel brush from Home Depot attached to my angle grinder and noticed the end on the driver side just before it rises flexes so much that the two plates are no longer level with each other no wonder rain and snow gets in causing rust !!! Used some fine Tuning with my sheet metal hammer and got them level again and Tomorrow I am getting that corner mig welded then I am using Eternabond tape ( Thanks Vic)
 

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