Cab over seam leak

vjstangelo wrote:
I notice many new Class C's are going to a full fiberglass nose on the cabover. What are the thoughts on these types of build?

Absolutely A "Winner".

B+ cap designs offer much less vibration, excellent aerodynamics, and improved handling characteristics. All are nice advantages and well suited for two people. But if we needed extra space to accomodate more people, I wouldn't give a seamless "C" a second thought.

Understand that we keep our rigs multiple decades so I have long term longevity in-mind. But most people switch rigs much more frequently. Buying a new seamed "C" is not of concern if you are selling it before it starts leaking.

I cannot recommend buying an old used seamed "C" because it is simply a big gamble. Some people bought old used seamed "C" and claim no issues. They gambled and won. Not to say the leaks won't start anytime soon.

Other points worth noting: Avoid other seamwork in corners. It is much better to have a crowned roof with roof-to-wall seamwork rolled over the edge on to the wall, and rear wall seamwork located away from corners around to the sides.

Example of rolled-over roof-to-wall seamwork. Don't let the paintwork mislead you.


Example of rear wall seamwork brought around to the sides.


Finally, the shorter/narrower/lower the rig, the stronger the house will be. A small box made of the same cardboard as a huge cardboard box will be substantially stronger. Same rules apply with motor homes.

I notice many new Class C's are going to a full fiberglass nose on the cabover. What are the thoughts on these types of build?

Drain off the water if there is any. Then take the banding off. Get some replacement stainless steel screws. Dry out the cabover with a fan if need be (this takes a few days). Put the banding back on and use the butil tape underneath it and screw it down with the stainless screws. Now re-calk it with flexseal. That's what worked for me on my '94.
Good luck!

Mine is the same. We have replaced the floor in the bunk and re-enforced it with an angle iron metal frame. I have had good luck with eternabond so I will probably employ that again on the cab over. It wont look the greatest with all the round edges and all but that stuff does keep the water out.

I have the same problem with mine. Its in the shop right now. The estimate is $4200

Fixing it right is a real nightmare by me. By the time you have enough bad material removed, you'll have something that looks like this. Rebuilding it will take a variety of skills & tools, and determination. This is why I emphasis a B+ if you can live without a over-cab bed. Or go seamless like a View or Born Free.

In that pic, something, maybe a flagpole, sticks out of the ground beyond the RV. At that point in the picture, is the curved image I see something bulging downward? From the bottom of the cabover? I ask because if it's sagging like a pig's belly, there's a lot of deterioration.
My concern is that water's getting inside above that corner, and the loose trim might be doing more to let water OUT than in.
Can you rig a pressure tester? A furnace blower, big leaf blower, ventilator, really strong fan? Close, maybe tape, all openings, duct the blower or whatever to a window or vent, and pressurize the coach interior. Then spray soapy solution (kid's bubble stuff) around on the outside and look for bubbles. You know you'll see them along that seam, but what you need to find is the source.

Silicone is NOT your friend when it comes to RVs. Get that stuff off as soon as is practicable and go with some Dicor and/or Eternabond.

Thank you for post , I put some clear RTV silicone on today ,temp fix until time to fix .. look at .. picture looks worse than it really is

This is a big deal and VERY common to Class C's. I have a 2003 Itasca and have a similar problem. I have tried searching the web for solutions. I will share some of the links I have found. I am collecting info while I formulate my battle plan. I hope to fix my water damage myself, in the meantime my leak is stopped with RTV silicone. If anybody has more links, please share.

http://www.ecalypso.com/
http://www.class-c-motorhome-info-made-simple.com/water_damage.html
http://www.irv2.com/forums/f87/bunk-water-damage-rebuild-93178.html
http://www.irv2.com/forums/f87/class-c-cabover-water-damage-132583.html
http://www.delamrepair.com/composet_2_002.htm
https://plus.google.com/photos/100179824430630761844/albums/5773296653657380769?banner=pwa

My damage is not as bad as the damage above, but it is not going to get any better. It is not going to fix itself. That pesky horizontal seam on the lower edge of the cab-over is the culprit. It is a design and manufacture defect common to a lot of Class-C's.

The fix? What I believe is that the whole floor of the cab-over needs to be replaced. While that is off, I will inject resin in the side wall of the cab-over and re-laminate the plywood and fiberglass skin. Since you do not have flat fiberglass side walls, damage there is hard to see, but expect it.

Good luck to you.

RVMike1