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Author Topic: Class C Cabover Rebuild  (Read 832 times)

emmaa

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Class C Cabover Rebuild
« on: May 09, 2017, 12:16:12 PM »
Hi all - I'm new here! 18 years old and just bought my first RV for $1500 -- it's a '94 Tioga Montara. The reason I got it so cheap is because the entire cab is water damaged. I've been scouring the forums and everything else I can find on the internet about rebuilding it and have gotten lots of good ideas so far -- I don't think that the inside will be much of a problem to rebuild (watch those words come back to bite me!) but the outside is really looking bad. I'll attach some photos, but the short of it is that it's looking like I'm going to have to replace the fiberglass on the outside because the bottom of the cab is detaching from the sides. What would be my best options for materials (sheet metal? fiberglass?) and sealing the seams (Eternabond?) I've never done anything like this before so it will definitely be a learning experience. Thanks in advance!


Molaker

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Re: Class C Cabover Rebuild
« Reply #1 on: May 09, 2017, 01:12:38 PM »
Emmaa, I'm the one you emailed about my cabover rebuild.  As mentioned, my website is being moved to a blog and is not ready for viewing yet, but I'll try to help you if I can.


First, the photos of your RV are almost duplicates of what I encountered.  I'm afraid you are in for a major job and is probably only financially feasible if you have tools, DIY skills, work space and, maybe, a bit of foolhardiness.


The bunk construction of a typical cabover (class C) makes a perfect water collection space because the outside skin traps the water and holds it there until rotting of the wooden portions of the structure cause things to come apart.  Just like yours has done.


Here's some photos of what I encountered.  I think you'll find yours to be much the same.




Tom & Joyce and Ditto the "don't tell her she's a dog" Westie
U.S. Navy (Ret)
2014 Winnebago ERA 70X 24' class B Sprinter chassis

emmaa

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Re: Class C Cabover Rebuild
« Reply #2 on: May 09, 2017, 01:31:05 PM »
Emmaa, I'm the one you emailed about my cabover rebuild.  As mentioned, my website is being moved to a blog and is not ready for viewing yet, but I'll try to help you if I can.


First, the photos of your RV are almost duplicates of what I encountered.  I'm afraid you are in for a major job and is probably only financially feasible if you have tools, DIY skills, work space and, maybe, a bit of foolhardiness.


The bunk construction of a typical cabover (class C) makes a perfect water collection space because the outside skin traps the water and holds it there until rotting of the wooden portions of the structure cause things to come apart.  Just like yours has done.


Here's some photos of what I encountered.  I think you'll find yours to be much the same.

Oh, wow. I knew it was going to be hard but hearing that it is a major job has me a little nervous. Financially, I can't afford to have someone else do the work so it's definitely going to be a DIY job. I do have the space and tools between my family and my boyfriend's grandparents, and I'm hoping that I have the foolhardiness and skills required too.

So - what did you do? Did you reuse the outer fiberglass or buy new materials?

Molaker

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Re: Class C Cabover Rebuild
« Reply #3 on: May 09, 2017, 02:08:27 PM »
As that was my 1st experience with this, I tried to salvage as much of the old Filon at possible.  That was not a particularly good choice.  #1 - the Filon has a thin layer of plywood glued to the backside.  Much of the plywood was rotted and had to be removed and replaced.  #2 - The edges of the Filon where the screws attached it were torn up and pretty rough.  This made for difficulty in reattaching things together.  So, in answer to your question, yes you can probably use the old Filon, but you'll have to balance the extra work to do so vs the cost of new Filon.  That said, Filon itself is no too expensive, but shipping will eat your lunch.  If you can locate a nearby mfgr that you can drive to, it would save a LOT of cost.  Try Googling "Filon".  It typically is sold by the foot from 102" wide stock.  The 102" is essentially the width of your RV siding.  Here's a possible source though not necessarily recommended, only the 1st in a Google search.

Now, to be totally honest, I had to rebuild mine twice.  It's a long story, but I will tell you that the 2nd time I replaced the front with new Filon and did not install the window that originally went across the front (one less possible leak source).


If you decide to accept this assignment, Determining the source of the leak and making sure it is addressed is just as important as the repair of the cabover.  Otherwise...


Some more photos - The 1st is the bunk bottom made with new Filon.  The others show the progression of rebuilding the front and covering with new Filon (no window).




Tom & Joyce and Ditto the "don't tell her she's a dog" Westie
U.S. Navy (Ret)
2014 Winnebago ERA 70X 24' class B Sprinter chassis

Molaker

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Re: Class C Cabover Rebuild
« Reply #4 on: May 09, 2017, 06:02:49 PM »
OK, I managed to piece together my 1st rebuild.  It's a page from my unfinished blog so if you stray from this page most images will not display.


Pumpkin Patch



Tom & Joyce and Ditto the "don't tell her she's a dog" Westie
U.S. Navy (Ret)
2014 Winnebago ERA 70X 24' class B Sprinter chassis

emmaa

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Re: Class C Cabover Rebuild
« Reply #5 on: May 09, 2017, 06:21:02 PM »
As that was my 1st experience with this, I tried to salvage as much of the old Filon at possible.  That was not a particularly good choice.  #1 - the Filon has a thin layer of plywood glued to the backside.  Much of the plywood was rotted and had to be removed and replaced.  #2 - The edges of the Filon where the screws attached it were torn up and pretty rough.  This made for difficulty in reattaching things together.  So, in answer to your question, yes you can probably use the old Filon, but you'll have to balance the extra work to do so vs the cost of new Filon.  That said, Filon itself is no too expensive, but shipping will eat your lunch.  If you can locate a nearby mfgr that you can drive to, it would save a LOT of cost.  Try Googling "Filon".  It typically is sold by the foot from 102" wide stock.  The 102" is essentially the width of your RV siding.  Here's a possible source though not necessarily recommended, only the 1st in a Google search.

Now, to be totally honest, I had to rebuild mine twice.  It's a long story, but I will tell you that the 2nd time I replaced the front with new Filon and did not install the window that originally went across the front (one less possible leak source).


If you decide to accept this assignment, Determining the source of the leak and making sure it is addressed is just as important as the repair of the cabover.  Otherwise...


Some more photos - The 1st is the bunk bottom made with new Filon.  The others show the progression of rebuilding the front and covering with new Filon (no window).

Right, that definitely makes sense. I went to look at the RV again tonight and definitely think it would be worth it to just order (or go pick up) some new Filon. So, in that first picture of your last post, you attached the Filon to the wood you used to make the bunk bed and then installed that entire piece? Then laid the other piece of Filon over the curve? Did you then use Eternabond tape to seal the seams?

Sorry for all of the questions - I'm really looking to pick your brain here haha. I'm determined to make this project work!

I also tried to access that blog page and it says that the blog is "open to invited readers only." It might be in the security settings of the blog? Thanks again for all of your help!

Molaker

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Re: Class C Cabover Rebuild
« Reply #6 on: May 09, 2017, 08:32:43 PM »
Sorry, I'll fix the permissions problem with my blog.  I had set it private while I worked on it.  Also, since my last post, I've managed to patch up my 2nd rebuild.  So, if you go through both, I think most of your questions will be answered.


Pumpkin Patch


Pumpkin Patch Part Deux


Let me know if you still have trouble accessing the blog.  I think I've got it set for 'public' now.
Tom & Joyce and Ditto the "don't tell her she's a dog" Westie
U.S. Navy (Ret)
2014 Winnebago ERA 70X 24' class B Sprinter chassis

Molaker

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Re: Class C Cabover Rebuild
« Reply #7 on: May 09, 2017, 08:59:24 PM »
Right, that definitely makes sense. I went to look at the RV again tonight and definitely think it would be worth it to just order (or go pick up) some new Filon. So, in that first picture of your last post, you attached the Filon to the wood you used to make the bunk bed and then installed that entire piece? Then laid the other piece of Filon over the curve? Did you then use Eternabond tape to seal the seams?

Sorry for all of the questions - I'm really looking to pick your brain here haha. I'm determined to make this project work!

I also tried to access that blog page and it says that the blog is "open to invited readers only." It might be in the security settings of the blog? Thanks again for all of your help!
Forgot to answer your questions...


Yes, I used Eternabond to seal all joints with this caveat...I used butyl tape between the panels and the frame.  Then used Eternabond under any aluminum trim that is screwed over seems and edges of the paneling.  Eternabond does a better job of sealing the screws, in my opinion.  The Filon is glued to the bunk bottom.  I used a special contact cement, but an even application of a good construction glue should work just as well.  As for the curved front section, you must construct a plywood structure then wrap and glue the Filon to that.  I used 1/8" Luann for that because it is much easier to bend without having to steam.  Contact cement works best there since contact adhesion is very helpful with assembly.


Of note, I used 1/8" plywood and some 3/16" plywood for the backing for the Filon.  However, I found that Coachman used Filon siding with what appeared to be something in between, probably 5/32" or equivalent metric.  Measure the thickness used by your RV mfgr.  It's not too critical on the front wrap-around or bunk, but if you must replace any side panels it's much better to use the 5/32" material so it doesn't change the overall width of the coach and affect the edge joint of the wrap-around.  The 102" width of the Filon stock is typically the width of the original wrap-around.
Tom & Joyce and Ditto the "don't tell her she's a dog" Westie
U.S. Navy (Ret)
2014 Winnebago ERA 70X 24' class B Sprinter chassis

emmaa

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Re: Class C Cabover Rebuild
« Reply #8 on: May 09, 2017, 10:27:29 PM »
Forgot to answer your questions...


Yes, I used Eternabond to seal all joints with this caveat...I used butyl tape between the panels and the frame.  Then used Eternabond under any aluminum trim that is screwed over seems and edges of the paneling.  Eternabond does a better job of sealing the screws, in my opinion.  The Filon is glued to the bunk bottom.  I used a special contact cement, but an even application of a good construction glue should work just as well.  As for the curved front section, you must construct a plywood structure then wrap and glue the Filon to that.  I used 1/8" Luann for that because it is much easier to bend without having to steam.  Contact cement works best there since contact adhesion is very helpful with assembly.


Of note, I used 1/8" plywood and some 3/16" plywood for the backing for the Filon.  However, I found that Coachman used Filon siding with what appeared to be something in between, probably 5/32" or equivalent metric.  Measure the thickness used by your RV mfgr.  It's not too critical on the front wrap-around or bunk, but if you must replace any side panels it's much better to use the 5/32" material so it doesn't change the overall width of the coach and affect the edge joint of the wrap-around.  The 102" width of the Filon stock is typically the width of the original wrap-around.

Thanks a million! I've already read through "Pumpkin Patch Part 2" twice. It is going to be my bible for the next few months. Thank you so much for taking the time to document your trials and errors, and ultimate success, and for answering all of my questions. I'm ready to get started on this project.

Molaker

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Re: Class C Cabover Rebuild
« Reply #9 on: May 10, 2017, 08:32:27 AM »
I'm happy to help.  Keep in mind as you tear into your project, your RV won't necessarily be built the same.  Different mfgrs have different  ways of doing thing.
Tom & Joyce and Ditto the "don't tell her she's a dog" Westie
U.S. Navy (Ret)
2014 Winnebago ERA 70X 24' class B Sprinter chassis

travelman

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Re: Class C Cabover Rebuild
« Reply #10 on: May 10, 2017, 06:48:28 PM »
I would check out Composet Products(delamrepair.com)  they offer a lot of cheap options for fixing water damage

blw2

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Re: Class C Cabover Rebuild
« Reply #11 on: May 11, 2017, 03:30:00 PM »
I had a roof leak...well actually the leak was at the front edge of the roof, right at the corners where the roof membrane starts, and the nose from the cabover stops....  right where the corner trim stops on top at the roof membrane
I also think that it may have been leaking because the skin forming the round nose of my cab over was cut short right up in that same area, so that the aluminum corner trim did not cover it to make a sealing surface.  I wish that I could have found a source for an extra wide trim (like this stuff I mean, only much wider on each leg... http://www.all-rite.com/aluminum-moldings/insert-moldings/m20-insert-corner-molding)
This is a side track for your purposes, but what i did since my nose cone skin was too short to seal.... After repairing and sealing with eternabond webseal to get it all back together, I took it to rvroof.com and had a roof sprayed overlapping the corner.  I feel pretty good now about it being sealed up.

Fortunately my damage was caught early and so my repair was much simpler than yours

But I agree with the advice to find and repair the leak(s)...and know that it's likely to not be right where the damage is

a couple of resources I had found that may be handy to you
using eternabond on the corner (actually this is a different brand)  the eternabond web seal is the equivalent
https://www.youtube.com/watch?v=366yEXwq86k

and read through all the bulletins and install instructions over at
https://www.eternabond.com/RV-Leak-Repair-Products-s/22.htm
lots of good infor there i think to help you btter understand which products you need and how to use them...
Brad (DW + 3 kids)
13 Thor Chateau 31L Class C on Ford E-450
'06 Silverado
'05 Rockwood Freedom 1910 (5-1/2 years)
former tent campers

Davemal585

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Re: Class C Cabover Rebuild
« Reply #12 on: June 24, 2017, 11:01:10 AM »
Emmaa, I'm the one you emailed about my cabover rebuild.  As mentioned, my website is being moved to a blog and is not ready for viewing yet, but I'll try to help you if I can.


First, the photos of your RV are almost duplicates of what I encountered.  I'm afraid you are in for a major job and is probably only financially feasible if you have tools, DIY skills, work space and, maybe, a bit of foolhardiness.


The bunk construction of a typical cabover (class C) makes a perfect water collection space because the outside skin traps the water and holds it there until rotting of the wooden portions of the structure cause things to come apart.  Just like yours has done.


Here's some photos of what I encountered.  I think you'll find yours to be much the same.
.


Hi,
Thanks for all the great info!  I'm in the middle of the same thing with my 2004 Coachmen Leprechaun.  I'm wondering if you could give me a name brand of adhesive to reattach the front skin to the plywood?  (the nose piece that wraps around the curves at the roof and just abve the cab if you know what i mean).  I bought some Titebond Fast Grab FRP panel adhesive but the test piece doesn't adhere to the 1/8 " plywood all that well.  I hoping not to use a contact adhesive, the type that you coat both pieces then press together.  That seems like it may be to trticky for me.  Any advice is appreciated
Dave

Molaker

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Re: Class C Cabover Rebuild
« Reply #13 on: June 24, 2017, 12:51:50 PM »

Hi,
Thanks for all the great info!  I'm in the middle of the same thing with my 2004 Coachmen Leprechaun.  I'm wondering if you could give me a name brand of adhesive to reattach the front skin to the plywood?  (the nose piece that wraps around the curves at the roof and just abve the cab if you know what i mean).  I bought some Titebond Fast Grab FRP panel adhesive but the test piece doesn't adhere to the 1/8 " plywood all that well.  I hoping not to use a contact adhesive, the type that you coat both pieces then press together.  That seems like it may be to trticky for me.  Any advice is appreciated
Dave
Perhaps a good polyurethane adhesive would work for you.  If applied from a tube, you should apply in a small diameter bead and zigzag it to cover as evenly as possible.  You would have to maintain pressure on it while the glue sets (clamps, weights, etc.).  I recommend attaching the Filon skin to the bottom of the cabover first.  There should be a row of staples or screws along there and an aluminum trim piece that covers the joint to finish it.  The bottom of the cabover is probably the smallest radius curve, so it works best starting there with the edge well anchored.  When I wrapped mine, I made sure the Filon was more than enough in length to cover beyond the point where it would join the roof.  You can cut it to length once it is wrapped and glued down almost all the way.  You will want the Filon to overlap the front edge of the roof a little when completed.

I attached a furring strip with clamps along the edge of the Filon at the top (the edge that will eventually join with the roof) and then attached heavy cord to the clamps and ran it back to the rear of the RV and anchored it to the rear ladder.  Then I could tighten the cord to pull and hold pressure on the Filon wrap while the adhesive cured.  Sand bags at the top where the wrap flattens out helps.  If you have a sheet vinyl flooring roller, roll the wrap extensively to compress the adhesive beads or, if no roller (as in my case), rub the entire surface with something round, hard, and smooth.  I used a rubber mallet laid on its side.  Look and feel for bulges which would indicate more pressure or rolling might be needed to fully engage the adhesive.  In some spots, tapping with a rubber hammer can help.

Of note, when the manufacturer first built it, the Filon was already laminated to the plywood.  I don't know for sure how it was done, perhaps by steaming the panels and rolling to make the curve.  But, since you are gluing the Filon to a curved surface, expect some bulges and areas of delamination.  If you have covered the area well with glue and rolled it well, the adhesive should span any gaps between the plywood and the skin and once hardened take any flex out the area.

FWIW, I used a fine-tooth saw blade installed backwards in my circular saw to cut the Filon.  It is not as likely to break or chip the edge that way.

Good luck.



« Last Edit: June 24, 2017, 12:54:16 PM by Molaker »
Tom & Joyce and Ditto the "don't tell her she's a dog" Westie
U.S. Navy (Ret)
2014 Winnebago ERA 70X 24' class B Sprinter chassis

zursch

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Re: Class C Cabover Rebuild
« Reply #14 on: August 30, 2017, 09:26:18 AM »
I am too beginning this restoration with my Class C.  Question for you all on the seams between the cab and sides.  Should I reuse the existing trim piece or do as this poster did with fiberglass seam...

http://www.rvforum.net/SMF_forum/index.php/topic,25767.msg567442.html#msg567442

What do you suggest. 

blw2

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Re: Class C Cabover Rebuild
« Reply #15 on: August 30, 2017, 11:21:26 AM »
I'd like to see how that fiberglass trim piece turned out.  I'd guess that if you have skills working with FRP, then it could be a great solution!

I looked into that corner insert trim when i was doing my repair.  I ended up re-using mine but found that i could have bought a new pre-bent piece from Thor.  What i really wanted was something with a significantly wider flange....something that would give a substantial increase in sealing surface area.  I could not find anything from Thor or aftermarket. 
As it is, that measly little 1 inch or so overlap isn't enough normally in my opinion.... and certainly wasn't enough where they made by nose skin too short....only giving 1/16 in or so sealing surface area under that trim.

I used eternabond's webseal under the insert trim to seal it up really well, then had rvroof.com  spray over the corners to seal it in hopefully permanently....
Brad (DW + 3 kids)
13 Thor Chateau 31L Class C on Ford E-450
'06 Silverado
'05 Rockwood Freedom 1910 (5-1/2 years)
former tent campers

LarsMac

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Re: Class C Cabover Rebuild
« Reply #16 on: August 30, 2017, 01:19:45 PM »
Thanks for this thread.
I am about ti embark on a similar "adventure."
My problem was that the seal along the bottom of the driver side popped open, Apparently in a wind storm, and let water run down the side, into the bottom pan of the overhead. But now the wood on the bottom, and the driverside is rotted and coming apart.
 
2000 Itasca Sundancer 430V
2007 Saturn Vue

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