Tell me what you think....

[wulfraat]

I’ve got what looks like the early stages of some rear end separation on my 2017 30’. The frame rail has about 1/8 - 1/4” of vertical play if you grab it and pull up and down with some force...

Video 1:

https://www.dropbox.com/s/l76lkj0vfw...Flex4.mp4?dl=0

Video 2:

https://www.dropbox.com/s/kysrivd6y8...Flex3.MP4?dl=0

I’m thinking that one of the elevator bolts securing the C-channel to the outrigger or rear cross member may be loose perhaps?

Have not pulled the belly pan yet to inspect frame rail for cracks which would be unlikely I’d think...

Tell me what you think!

Thanks!

[GMFL]

Have you drug the tail?
I think you are correct on you theory about an elevator bolt being loose or possibly broken.

Dropping the rear bellypan should give you the information you need to make the necessary repairs.

Good catch by the way. Being in tune with your Airstream is a great way to prevent bigger problems from happening.

[wulfraat]

Before I got my lift the tail was drug twice perhaps.

Once by me exiting a grocery store parking lot and oddly enough once in the parking lot of where I had the lift installed.

I feel that it may have tweaked something. I always go very slow over dips that I know are close.

When it was dragged in the parking lot a fork lift was being used to maneuver the trailer slowly around. We had to hammer the skid plates a bit to get them vertical again, they got pulled a bit on a turn....

PS - post lift have never dragged the tail again yet

[GMFL]

You probably broke a elevator bolt.

[wulfraat]

Originally Posted by GMFL

You probably broke a elevator bolt.

Thanks yes this is my theory great for others with more experience to weigh in - appreciate it Ronnie!

I’ll find some time to drop the pan and investigate.

[OTRA15]

Originally Posted by wulfraat

I’ve got what looks like the early stages of some rear end separation on my 2017 30’. The frame rail has about 1/8 - 1/4” of vertical play if you grab it and pull up and down with some force...
. . .
Video 2:

https://www.dropbox.com/s/kysrivd6y8...Flex3.MP4?dl=0
. . .

Are you sure that the steel piece which is moving is part of the "frame rail?" The way it is moving suggests to these eyes that it is fairly short, with the pivot point for the movement only about 2-3 feet forward IMO.

Is it possible that this steel piece is perhaps bolted to the trailer's main frame in there, and that your drag events simply messed around with the bolts, and/or with the holes for the bolts, thereby allowing the play you see?

Looking forward to your removing the belly pan, but first I would suggest thinking about where the pivot point for that movement is. You should be able to "feel" this better in person IMO.

Good luck,

[wulfraat]

Originally Posted by OTRA15;

Are you sure that the steel piece which is moving is part of the "frame rail?"

Yes it is the frame rail itself.

Cracked frame would be another potential issue but I’ve never done anything to cause a structural failure. But who knows...

The 2017 FC, International and Classic all share the same 30’ frame. My trailer is rated to 8,800 lbs due to the 4.4K dexter axles installed and I run it wet ready for camping at 8,200.

The classic has a GVWR of 10,000 lbs (has 5k dexter axles) and is heavier in the back due to the furniture / etc.

I note this because I like to think that the FC/International 30’ are somewhat “overbuilt” from a substructure perspective, since they share the same frame / shell as their big brother the 30’ classic.

All that being said anything is possible and appreciate the additional thoughts here.

[OTRA15]

Thanks . . . but that much movement seems inconsistent with a 30' long steel rail moving at all IMO. Wish I could feel it physically in person. Your fingers will "know" where the fulcrum pivot point is IMO. Fingers don't know the structural theories, nor can they see the drawing. Not trying to be argumentive . . . FWIW!

[wulfraat]

Originally Posted by OTRA15;

Thanks . . . but that much movement seems inconsistent with a 30' long steel rail moving at all IMO. Wish I could feel it physically in person.

Me too! (Re Additional hands on evaluation) [emoji4]

It does take quite a bit of weight / force to make it move for what that is worth. More to come.....

[uncle_bob]

Originally Posted by wulfraat

.....

The 2017 FC, International and Classic all share the same 30’ frame. My trailer is rated to 8,800 lbs due to the 4.4K dexter axles installed and I run it wet ready for camping at 8,200.

The classic has a GVWR of 10,000 lbs (has 5k dexter axles) and is heavier in the back due to the furniture / etc.

I note this because I like to think that the FC/International 30’ are somewhat “overbuilt” from a substructure perspective, since they share the same frame / shell as their big brother the 30’ classic.

All that being said anything is possible and appreciate the additional thoughts here.

Hi

You could also look at the same data and conclude that the 30' Classic is a bit *under built*. Based on the degree the back end moves with modest force from the stabilizers, that would be my guess ..... doubly so after going around on the issue with JC and the verdict coming back "that's normal in a Classic ....".

Bob

[wulfraat]

Originally Posted by uncle_bob;

Hi

You could also look at the same data and conclude that the 30' Classic is a bit *under built*. Based on the degree the back end moves with modest force from the stabilizers, that would be my guess ..... doubly so after going around on the issue with JC and the verdict coming back "that's normal in a Classic ....".

Bob

Appreciate the insight Bob.

[guskmg]

The vertical movement (play) is caused by the lower skin attachment rivets being pulled down by the floor/frame and shell's up and down movement. One cause, not mentioned: is too much weight in the rear bumper storage compartment. In a few more cycles, when the lower rivets pull out, the floor and frame will completely separate and the only alternative is to repair the rear end structure. Colin Hyde in Plattsburgh, NY, knows a lot about the best way to "repair rear end sag." Although Airstream Service does this mod/fix, I believe Colin has better results. I have experienced this twice,
guskmg

[wulfraat]

Thanks for this. Removing the rub-rail trim should expose the lower rivets and I should be able to see if any are being pulled by the skin correct?

I only keep a water hose and wheel chocks in the bumper. I don't use the rear trunk so it is basically empty as well.

[Wazbro]

Another common cause for rear end separation is floor rot. Do to AS using plywood as a structural spacer between frame and shell. When it rots it leaves a space for movement to start doing damage.

[GMFL]

Look what showed up at my shop last night...... looks like they have the same problem only this is caused from a rear receiver installed on the trailer.

[OTRA15]

Originally Posted by Wazbro

Another common cause for rear end separation is floor rot.
. . .

On a 4 year old trailer?

[GMFL]

Originally Posted by Wazbro

Another common cause for rear end separation is floor rot. Do to AS using plywood as a structural spacer between frame and shell. When it rots it leaves a space for movement to start doing damage.

Floor rot is caused by rear end separation

[Wazbro]

Originally Posted by OTRA15

On a 4 year old trailer?

Yes water leaking onto plywood sub-floor for 1 year is enough to do lots of damage.

[Wazbro]

Originally Posted by GMFL

Floor rot is caused by rear end separation

Then how does it happen in the front of the trailer?

[uncle_bob]

Originally Posted by Wazbro

Then how does it happen in the front of the trailer?

Hi

It's the colony of mice using a bunch of very small buckets to bail out their nest in the back of the trailer ...

Bob