1977 Sovereign Frame Reinforcement

[superdave74]

Hello,
We're redoing a 1977 Sovereign mid bath model. I've read about issues with rear baths and frame cracks. We have most of the subfloor out and the frame appears to be in great shape with just a touch of surface rust, so we'll be sanding and using POR 15.

We do plan on rebuilding the interior with with some heavier weight materials then the thin aluminium sheet metal and luan used in bathroom walls and cabinets. Guesstimating an extra 400-600 lbs perhaps spread throughout.

Are there any "prone to failure" areas or known design flaws that we should address?

Thanks,
Dave

[Lumatic]

More common than frame cracks, which usually appear in the axle area, is "rear end separation" Do a search and you will find out more than you ever want to know. Same causes for both. There are 2 causes:
1. The cantilever effect of the distance from the axles to the bumper.
2. The body of the coach is attached to the frame and floor by an angle iron. The design of the rear of the Airstream is prone to leaks. The leaks leads to rusting away of the angle iron and subfloor rot which leads to separation of the frame and floor from the body of the coach.

Airstream has a fix for both. "elephant ears" are welded to the frame for reinforcement.

[jessl_99]

What do the elephant ears consist of?

[dbj216]

Hello from Colorado: Welcome to Air Forums. There are a lot of folks who have walked the path you are on. Participants here are willing to help answer questions.

I have a 75 Overlander 27' rear bath. You are lucky to have the center bath layout. You are lucky to have a solid frame based on your inspection. You will know more after you clean and paint the frame. Inspect carefully as you go.

I'm surprised in the lush southeast that your trailer doesn't have much frame rust. Southwest trailers may have less rust problems. My trailer spent considerable time in Louisiana and did have some rust holes. I also had rear end separation and frame sag. I have repaired all that now.

"Elephant ears" are actually a cut out of the exterior skins at the rear of the trailer. Airstream and some dealers open up the rear skins of the trailer to gain access to the rear cross member and rear body bolts to repair rear end separation. It is easier than taking the bath out of the trailer and the interior skins at the rear off. I opted for the bath out approach as I had the time and didn't care to cut open the exterior skins at the rear.

Frame cracks can appear in the axle plate around the axles. Frame buckling can occur just after the axle plates. Airstream does sell a "stiffener kit" that is welded or bolted to the existing axle plate. This strengthens this area. Others have added structural members to the frame from the axle plate on back. Most of us hire a good mobile welder who has experience in these sort of things. I had 9 areas that we welded up on my frame. However, several of these were adding mounting angle irons for my new waste water tanks.
You may like to pursue my project thread linked below and see what I did to my frame.

Take note of the "gross vehicle weight rating" on the plaque on your trailer. I might say something like 8000 pounds. It may have weighed 6500 dry out of the factory. I wouldn't exceed the GVWR of your trailer with your remodel projects. You may not need those fancy granite countertops on solid oak cabinets if you know what I mean.

David

[jessl_99]

I owe the previous owners for taking care of it over the past 50 yrs. I would hate to cut the outer skin but I can see where it is necessary. I have a spot forward of the axels where the plywood is solid and dry but a bolt or two has pulled out and a two foot section of body/C-channel is not secure to plywood. I can press the body into place with my hand. Has anyone out there attempted to secure a C-channel to the plywood sub with rivets or expansion bolts. I have removed the belly pan so have full access underneath.

[Janssvt]

We had a 79 Excella 500 with rear bath. When we had the brakes re-done they checked the frame and it was just starting to "stretch" over the wheels so they put a sleeve over it. Now we have a 34 with Center bath and we had the elephant ears fix on it a few years ago. You can tell that you have sag when the compartment door on the back starts to get a gap on either side (or both) on the top. Friend of ours had sagged on both sides to the point that the lock would not hold the door in place. Ours sagged on one side. We have the elephant ears on the outside and it doesn't look bad, if you go to sell it, peolpe will know you had the problem fixed, If you ask Airstream about it, they will say they didn't know there was a problem. Same answer they gave us about the Dexter brake pads. Pads were glued, not riveted, on to back plates and the glue let go. Pads floating around inside is not good. Dexter sent us 6 replacements free without a question.

[Lumatic]

Originally Posted by Janssvt

We had a 79 Excella 500 with rear bath. When we had the brakes re-done they checked the frame and it was just starting to "stretch" over the wheels so they put a sleeve over it. Now we have a 34 with Center bath and we had the elephant ears fix on it a few years ago. You can tell that you have sag when the compartment door on the back starts to get a gap on either side (or both) on the top. Friend of ours had sagged on both sides to the point that the lock would not hold the door in place. Ours sagged on one side. We have the elephant ears on the outside and it doesn't look bad, if you go to sell it, peolpe will know you had the problem fixed, .

I think I may have the "stretch" issue with my 34. Doesn't seem that bad and doesn't seem to be getting worse. Took me a while to notice it. First time I heard about this. How serious a problem is this? and, what did it cost to have the elephant ears installed? Thanks

[dbj216]

Hi Lumatic: Have you done the "bumper bounce" test? This test is definitive of "rear end separation". Stand on the bumper of your trailer, steady yourself, then bounce on it as if your going to dive off a diving board. Look for a gap to open up between the body molding and the frame of the trailer. If a gap opens, then the body isn't well attached to the frame at the rear.

If the frame rails lose support in the rear, they can droop or sag as the trailer is pulled down the road, especially over rough roads. You might also check the floor level front to rear in the middle of the trailer, and then check it at the rear of the trailer. You would expect the same bubble observation, but if the rear end is sagging, the rear floor level check will show a difference. Last you can probe the rear subfloor with an ice pick as close to the rear interior skins as possible. Look for rotted out areas of the subfloor, especially over the frame rails. These are the tests I did on my 75 Overlander and all of them were bad. Diagnoses confirmed!

I think it is unusual on a 1993 trailer to have this problem. It is mostly found on 70s vintage trailers.

"Elephant Ears" is a goofy description of the cuts made in the exterior skins, right and left, to allow access to the rear body to frame bolts and allows access to replace the rotted out subfloor back there. Here is a link to some photos, I hope:

https://www.google.com/search?q=Airs...EXsytHd36YX9M:

Airstreams are of "semi monocoque" construction. The frame holds up the body, and the body holds up the frame. Both components are rather weak by themselves, but when attached together, with the subfloor between them, they become quite strong. When the subfloor rots, and the body attachment bolts rust out, then things start to flop around.

Hope this helps...

David

[Lumatic]

Originally Posted by dbj216

Hi Lumatic: Have you done the "bumper bounce" test?

I don't have any rear end separation or floor rot issues. But there seems to be a slight sag to the rear of the floor inthis 34 footer. The floor seems very stable though.

The rear compartment door is a bit sticky, but I don't see any unusual gaps.

The only dent on the whole trailer is above the bumper curbside. I suspect at some point in it's history it was hit in the rear. maybe this has something to do with the "stretch".

As I said earlier, the trailer floor feels good and solid. I don't want to create a problem where one does not exist. But I wonder if there is a stretch if this could lead to a frame crack.

Using a level at different spots on the floor sounds like a good idea.

The area over the fender wells also shows no bulging.

[Janssvt]

The older 31s with rear bath were the ones that had frame stretch and rear sag BUT 34s into the 2000s are known to have it too. We had it, and we know of at least 4 others just in our area who had it, one had to have the front done too. Have a friend with a 2000 31 that just had his fixed. We had ours done in Grand Rapids, Mi. at Woodland Travel Airstream. It was about $1200.00 to do.