1970 New to us Ambassador reality check

[2002sheds]

Hi David, Al, All,
David, thanks very much -- I am getting a clearer picture.

Al, Sorry if I am testing your patience. I should not have written "aluminum" and "tank box". Mine had enough galvanized sheet metal to know what it is.

What I am asking is whether the galvanized tank box is also covered by the belly pan. I am missing a huge chunk of the belly pan in that area, and wonder if the fairly thick and stiff aluminum could serve as both the tank box bottom and the belly pan in that area. Not having owned an Airstream before, I do not know what is supposed to be there.



Thanks,
David

[ALUMINUMINUM]

The .025 belly skin keeps the insulation clean and streamlines the underside of trailer. More importantly, it keeps the ratons out.


If you don't entirely cover the tank area underside with belly skin, you're inviting destructive, odoriferous passengers, their nests, caches and larders, urine, feces, diseases, cemeteries…


It's easiest if you rivet a frame-wide .025 or .032, 5052 or 3003 aluminum sheet onto the existing bellypan, then from there, onto where you choose to terminate it at or beyond the rear-most angle-iron area.



The bellypan doesn't have to be a beautiful, continuous front to rear, or side to side sheet. It can be a patchwork of old license plates and road signs, as long as it seals against intrusion.

There is no rear attachment-bumperbox flashing shown in this marginally accurate "expanded" sketch. There are differences between '68 & '70.

[2002sheds]

Hi Al,
I think we are much closer to being on the same track. I have a road sign that I plan to use as the bottom of the box and the belly pan simultaneously.

The underside of our Ambassador has the aluminum belly pan all the way to the area of the tank. It still exists on either side of where the tank box will reside, so my thinking is that I can tie the road sign into this whole business and provide not just a floor for the tank box but also seal off the entire area from intrusion.

I also LOVE the sketch !:-) Two things, however:

1. I feel really bad for that fish.
2. No matter how innocuous that raton looks, it still gives me the willies. There were two (probably) Kangaroo rats living in the ceiling when we first saw the Ambassador. One was poisoned, the other made the 120 mile journey to our house but jumped out almost immediately after being rattled and shaken for 3 hours. Our house is semi-rural, so perhaps he (or she) went across the street to the wilds there. Otherwise, our cat or three dogs would have likely found it by now.

I also plan to treat the very back end in an almost identical fashion to yours, in terms of the bumper box. There is no material there now, so I am planning on separating the rear of the trailer as you have (and, I think, has David from Colorado) and using steel mesh as the front wall, sides and bottom.


Thanks,
David

[dbj216]

"If you don't entirely cover the tank area underside with belly skin, you're inviting destructive, odoriferous passengers, their nests, caches and larders, urine, feces, diseases, cemeteries…"

I don't think Aluminiuminum likes mice too much.

Being a lazy sort, I used a roll of .025 thick 5052 aluminum 48" wide. I'd measure and cut a piece about 65" long and work my way from the rear of the trailer to the front with 48" side to side belly aluminum. This was easiest for me as I don't have a good way of handling a BIG sheet of aluminum.

My Overlander belly pan will start at the bottom of the rear bumper and cover everything to the front of the body. I make sure I seal up all potential mousie entrance holes.

David

[2002sheds]

Hi David,
There is still a bit of confusion about what I am asking -- sorry if I have caused it!

I completely agree that the tank needs to be surrounded on 5 sides with metal (and styrofoam on the bottom and edges). I also agree that the entire bottom needs to be covered, to avoid unwanted visitors.

What I am asking is whether there needs to be TWO layers (1 of galvanized sheet metal or some other metal that is the bottom of the tank box, and a second (in my view repetitive) layer of belly pan aluminum. It seems to me that the aluminum road sign could serve as both the tank box bottom and the skin in that immediate area, and the remaining needed aluminum tied into that piece.

There could very well be a great reason to not do it this way -- I just don't know what it is offhand...


Thanks!
David

[rugjenkins]

It may be easier to run a sheet of belly pan material over the tank box. It will be easier than welding belly pan attachments. Just span to cross member to cross member. It really up to you. I'd span it (belly pan) over the tank and put some sikaflex between the two to avoid accidental putting a screw into the tank.

[2002sheds]

Hi Matt,
Cool idea. The belly pan is missing in the specific area of the tank and straight back from there.

In other words, there is aluminum that covers the areas outside of the frame where the tank box is. I need to provide cover for the space between the frame that includes the tank box and that 52" (or so) wide "stripe" that goes to the rear.

I was thinking that I could attach the aluminum construction sign to the frame (running sealant along there is a great idea) and have it travel to the rear support member (if that hangs low enough), then cover the last 6 inches or so with thinner aluminum, so that it more easily follows the contour of the rear of the coach.

I do not intend to to run the belly pan past the rear of the AS. I will look again tonight or tomorrow and snap a picture. There may still be aluminum on the rear of the AS that I forgot about...

Thanks,
David

[rugjenkins]

Sounds like you have it figured out. Don't over think the concept. These are fully enclosed campers. The belly pan "wraps" the bottom. How you want to do it is personal preference. Your plan should work great. I did a similar construction on my tanks the same way. Honestly, your probably the only person who will ever see it, [emoji12] most people will see the shiny upper side and drool. [emoji13]

[2002sheds]

Hi Matt,
You are a gentleman and a scholar. Have a great evening!

[ke6gkv]

hello Dave, when i redid my 64 overlander, i put a removable section under the tank. accsess to your tank less of a headache.doing the same on my 80 caravelle under my bathtube area. kurt

[2002sheds]

Hi Kurt,
Definitely. I was thinking that too -- attach the section of (in my case) road sign with screws, in case I need to get at the tank again.


Thanks,
David

[2002sheds]

Hi All,
I finally took pictures to better explain my madcap theory... the first shows the non-existent bumper storage area (except for the lid, which survived). The second shows the rear of the AS from the inside. The belly pan is intact on the sides pretty much all the way back, but the entire area where the tank goes and to the back is gone...

[2002sheds]

Hi All,
Some more frame and belly pan pics. In the frame pics (the first two), it is clear that when a PO hit something, the frame was slightly tweaked at the back. The tank support angle iron pieces have been removed, but the forward-most angle iron has a HUGE curve in it, and even the tank support tabs that are welded to the frame were bent... to me, it looks as if the angle iron tank box supports took the brunt of the collision, and when they bent upwards they bent the angle iron support tabs and pulled the frame inwards (more on the street side than the door side. Measurements bear out that the frame members are not the same distance apart anymore, getting closer to each other as you work your way back. Any advice about pushing the frame back apart will be welcomed -- even if the advice is to leave it and fill the gap.

Pay particular attention to the gap between the piece that is riveted to the frame member and the frame member itself. On the street side, it is over 1/4" and the rivets were ripped right out of the aluminum support piece.

The second set of pics is showing where the belly pan was destroyed/ripped (at the point where the tank box lives). These two pictures show the belly pan underneath that part of the frame... is the dried gunk on the frame a bead of sealant? Did the belly pan go ABOVE the lip on the bottom of the frame and BELOW the tabs for the tank support in that area? Inquiring minds would like to know...

[2002sheds]

Hi All,
Today has been a post-fest. Now I am adding a few more pictures that relate to the frame.
The first picture shows what I plan to use to replace the corroded steel angled piece next to it. I am not 100% of the name, but it helps tie the rear of the shell to the U channel, floor and so on. Part of this had bucked rivets through the shell.

The second picture shows much heavier angle iron than what came out, in terms of the tank box supports. I bought the material from a local metal scrapyard, and grabbed an extra piece. The lighter weight angled steel is from the back of the road sign that I plan to use as I patch up the bottom. I am unsure if these will get used in this project or not -- probably not.

In other news, I am quite thrown off by what I found when I removed (mostly -- it is held on by on rivet) the sheet aluminum and door for the rear storage compartment. The rear body/frame support (upside down "U" channel?) is further back than I realized. I am sure it is for a very good reason, but it does make separating the body from that box a bit less elegant... I have to give this some more thought, as I know I want to eliminate the "flashing into the rear plywood" aspect of the original design...I guess one possible way to go would be to cut out that rear brace and move it towards the front enough to allow for a cleaner line for the sheet metal...thoughts?


Thanks,
David

[dbj216]

I think it comes down to "builder's choice". That's what I do on my Overlander.
You're going to mount a water tank that could weigh 250 pounds full. So how will you hold the tank up and not let it move around? Make a tank box that fits in the space and is supported by the frame members. The bottom of the tank box can be anything you choose, e.g. old road sign. It just has to support the weight and not let rodents in.

That angle iron is called the rear hold down plate. It attaches the rear of the body to the rear most crossmember. Airstream rightly used solid rivets bucked tight as they are the strongest. The front hold down plate likely has two rows of bucked rivets holding the front of the body solid. The rear has only one row.

These old trailers need lots of work to get right again. Doing it ourselves is part of the fun. We just got to dig in and make it work somehow. I didn't build a tank box. I didn't hinge it to the cross member. And I bought a bigger tank because I had the room. I sketched up some supports that were strong enough and still allowed room for a drain line from the new gray tank. I will use belly pan aluminum to cover the whole mess.

Colorado David

[2002sheds]

Hi All,
After closer inspection, I have realized that the lower rear shell area of the AS has actually moved/sagged relative to the frame.

The first picture is of the rear support member, which seems to be sticking out the rear of the AS. The second is taken from inside and show the holes through which the bolts go to secure the connection between the shell (upper body) and floor/frame. These holes are supposed to line up, but they are off by about 1/2 inch (they look closer because of the camera angle) — about the distance that the rear support member sticks out the back in my previous picture...

Maybe I can separate the Stinky Slinky box after all!


Thanks,
David

[dbj216]

I don't think the body has shifted on your frame. That would take a rear end collision by a fully loaded dump truck.

Your first picture is telling. I see a "surgical scar" some call an "elephant ear" where a rear end separation and rear crossmember was likely repaired sometime in the history of your trailer. This is the external approach instead of taking the bath out of the trailer to gain access. This helps explain why your rear cross member looks different. And the repair shop may have used a structural steel member that was bigger than the original. It does create the infamous "shelf" where rainwater will run off the body and can run into the subfloor. You gotta seal this joint up good. I would take the molding off first.

The second photo showing misalignment of the C channel hole and the frame hole doesn't surprise. It looks like the C channel hole was enlarged at some point. I don't think it is an indicator of any body shift. Use a big washer when you put it back together.

Here is a photo of my 75 Overlander with the original rear crossmember. It does not stick out behind the body.

Colorado David

[2002sheds]

Hi David,
I may not have been as clear as I should've been in my earlier post. The very back of the shell, C-channels, etc. are not lined up with the support member. I have looked as closely as I can, and see no evidence of an old support member that was cut out.

The rear shell, C-channel, etc. can be fairly easily pushed slightly to the rear, once again lining up the holes. To me, they got messed up as everything was rotting away and the whole thing was shaking. They certainly don't look like cleanly drilled holes...


I see what you mean about the Elephant Ears. I need to read up on it some more, but I thought it referred to a method of repairing the rear floor without removing the bath. Maybe this was done a long time ago, but the original elevator bolts were still in the board that I removed, and that board had not been spliced.

Color me confused!


Thanks,
David

[dbj216]

Okay, I'm good at confusing fellow Forum members. The surgical scar lead me down the wrong path. It's hard to draw conclusions without seeing and touching the trailer.

The external method of repairing rear end separation is well explained by Andy af Inland RV. I found his post by searching "rear end separation repair". Maybe even Jackson Center does it that way. It is certainly faster. I don't know any other reason someone would cut into the rear body that way, but maybe there is.

Onward and upward...

Colorado David

[2002sheds]

Hi David,
Thanks for your post. I read a bit about the elephant ears repair approach, and it seems obvious (as you pointed out) that it was done on this AS. There were enough holes/bolts through the U channel to weigh down the back end of this AS by themselves. I didn't realize until you brought it up that they might have been added sometime after the original construction.

I thought the repair was a method for replacing part of the floor, but instead discovered (for me, anyway) that it was all about additional hardware securing what was left of the original floor -- clearly a losing battle in the (even slightly) longer term. Below is a picture of the floor that came out (two cuts were made to facilitate its removal), included as visual proof of the ultimate result of not taking on the more involved solution ...

I am still pretty sure that the shell has "curled inward" (I don't know how else to describe it) at the point where the bottom of the shell meets the frame support. The whole thing (U channel included) can be pushed outward by hand, which then lines up those 15 million holes. I think my approach is going to be to do that re-alignment and also minimize the number of cuts/holes in the plywood (the original had some shoe box-sized holes cut here and there) as I put it back together, in the hopes of helping maintain its -- (using some of my favorite words ) Structural Integrity. That, along with sealing the plywood the best I can and trying to eliminate any anti-flashing situations that sped the demise of the first sheet o' plywood.


Thanks,
David


Thanks,
David