Crack at joint, cabover to body

[BillHoughton]

I've noticed a crack at the joint between the body of the RV and the cabover; the cabover, at the sides, seems to lap over the body. One side's tight, but the right side has a crack that gets wider from top to bottom, shown here:

At its widest, at the bottom, it's about 3/8" wide.

Is this a sign of a structural problem? I don't see evidence of sag, and the joint where the cabover sits atop the cab proper (the part built by Mercedes) seems to be tight and stable. I'm not seeing signs of cracks in the adjacent body-to-cab connections below that crack (haven't yet crawled up on the roof to inspect). Are there tests/checks I should be applying/making to determine if I've got any structural issues?

If it's not structural, I assume I should caulk it. I'm familiar with architectural caulking practice (houses and the like): thoroughly clean out the crack, push backer rod into the crack as soon as it's large enough that I can do so, and apply and tool smooth a suitable caulk. Several questions there:

1. Is there any difference in the steps in caulking with an RV?
2. In architectural practice, you never caulk the lower side of a crack like this; any water that gets in needs to escape, and water always wants to flow downward. Would that be true here as well?
3. Any recommendations for a caulk? It would clearly need to be highly flexible, with good adhesive properties. Sikaflex makes a lot of good caulks, and I imagine one of their products would be a good choice, but I want the best/most suitable product here.

If there's something else I've forgotten to ask, I'll be grateful for that, too.

[BillHoughton]

Well, then, yes, mine is an early model. That little five cylinder is a determined engine. Not powerful, but it won't give up. I said, when we first got this, that it reminded me of the world's largest VW van: slightly odd steering wheel angle, underpowered but willing to haul, can't see out the back windows. I do like it.

[CharlesinGA]

I consider the "early" models to be those on the 5 cylinder chassis,

I purchased in Sept of 2015 at 18K miles and the gap was there then, and hasn't changed, it now has 29K mi on it.

At this point, I haven't done anythning, though I probably should seal it. The MH will be for sale this winter and I have a few items to take care of before it goes, guess this will be one of them.

Charles

[BillHoughton]

CharlesinGA wrote:
Is this an early Winnebago View or Navion? sure does look like it. I have the same issue on the drivers side, but not the passenger side.

Charles

Not sure what constitutes "early." It's a 2007 Itasca Navion.

How long have you had the problem, and has it been stable or gotten worse? And what did you do about it?

[CharlesinGA]

Is this an early Winnebago View or Navion? sure does look like it. I have the same issue on the drivers side, but not the passenger side.

Charles

[youracman]

Somehow Bill, the phrases/terms "structural failure" and "caulking should be sufficient" seem to me mutually exclusive to me. On the other hand, if this area of failure involves just a non-load-bearing face sheet, maybe a caulking/sealant fix does make sense at that. Maybe the young man was using the terms bond failure and structural failure interchangeably?

You're obviously "on top of it" in any event. Really hope the fix works out well .......... bet it will.

From day one, I have been in the "never silicone near my rig" camp (like so many RVer's.) But then I have since found that the factory used a special silicone blend on certain areas on my roof....... and those areas are still intact and crack free after 11 years! Go figure.

Safe travels ................

[BillHoughton]

A young man at Winnebago's customer service line says that bulging or depressions on the panel, inside or out, is a sign of structural failure, and that caulking this area should be sufficient. From what I described to him, he did not feel that there's any structural issue.

I'll be doing that, but will still be inspecting the area regularly.

[pauldub]

I should have done my anti-silicone rant earlier. Once you use silicone, nothing will ever stick there again and you will not be able to successfully recaulk in the future. Not even new silicone will stick to old silicone. A urethane or polyurethane will serve you better.

[ron_dittmer]

I would be tempted to clean it and caulk it with outdoor-rated silicone, injecting the caulk deep inside. The silicone caulk will seal and also provide great adhesion to hold the two sections together. Inject the caulk deep inside, then immediately after, wedge a side-ways 2x4 "T" against it to a tree or building. Then as the caulk is squeezed out, re-shape and caulk more for a water-tight seal and decent finished look. Keep the top of the "T" made of 2x4s pressing against the side of the rig for 48 hours to allow all the internal caulk to cure completely for best adhesion and long-lasting results.

Also check the roof joints to make sure no water enters there and out the side you are repairing.

If I am wrong, then go deeper researching the cause and ultimate solution involving serious disassembly.

[ronfisherman]

To me it looks like a water leak has caused material behind to expand. I would look for the leak. Do not seal the area completely. This will trap water behind crack and send it to another area.

[ksg5000]

Haven't seen that one before - with any luck it's just loose trim but if it were my rig I would be concerned until I knew what it really was. I would either take the rig down to dealer or maybe look for some threads where people have rebuilt their cabovers and see if you can find appropriate picture that would indicate how that portion of the cabover is attached to the main body. If I found someone who rebuilt their cabover I might send them a PM to get their input. Just a thought.

[ScottG]

#2 You want to seal the entire gap.
#3 I would use Dicor NON SAG sealant. You can get it in a similar color to match your RV.

[SidecarFlip]

Something going on underneath to cause that.