rear end sag

[bhsl8]

As some of you know I recently lost my AS to a very inattentive driver. In anticipation of replacement I have been browsing a bit. There are several units listed on eBay that I am watching and I have a question regarding the "dreaded butt sag".

Item #2424415960 is a rear bath 31' unit that looks like it is sagging to me. I see it lower in the rear and a bit of crease near the rear wheels. Is this indeed indicative of the sag and is this sufficient evidence to stay away from such a unit?

Thanks in advance to you learned ones of Airstreamdom.

[thenewkid64]

Brouck,

I am not seeing anything in the pictures that would lead me to belive there is a sag issue on that unit.

There is some skin wavyness in front of the wheels, but usally the symptoms show up behind the wheels. It looks like the unit was "updated" to look newer and the lower body wrap does tend to hang down a bit to cover all the way to the frame rail. This could be why it looks lower in the rear.

Other than the awning over the front window(an affront to the shape and design in my book) it looks like a nice unit.

A picture may be worth a thousand words, but nothing beats the old mark 1 eyeball!

[Pick]

That unit looks OK, to me. I did not see any "elephant ears" on the back, so it has not had the update, but it may not need it. Looks tight around the rear bumper. Price is not bad so far.

Some camera lenses can contribute to a "curvey" look also. Like Brett said, nothing beats beats "being there".

[Tripp]

Wavyness behind the rear wheelwells in itself is not an indication of rear end separation. The easiest way to inspect is for someone to stand on the rear bumper and "bounce". have someone look for any movement between the body and rear bumper area. (straight from the man himself-Inland Andy) I think the wavyness can be caused by the multiple compound curves the aluminum must follow in that area.

I have a 73 31' Center Bath with the same wavyness, but NO indication of rear end separation. As I understand it, if the rear end separates, the body of the trailer will remain elevated and not sag with the frame due to the "aircraft style" construction.

The only way to be sure is to see it in person!


Tripp

[bhsl8]

Thank you all. I guess it would be well to see the problem in person and obviously to inspect a potential purchase first hand but as we know it isn't always practical. I just keep learning as I go.

[Inland RV Center, In]

I am not sure about rear end separation on the Excella.

But, I am pretty positive that it has bad axles.

Good axles would display more of the top of the tires.

Andy

[Chas]

I've got a bit of waviness at the front and rear of my fender areas as well. I have jumped on the bumper and get maybe a 1/4 inch of movement out of it which doesn't seem excessive to me. Maybe I should post a pic so "EagleEye Andy" can give me his expert opinion? He has already seen my axles and says "they appear to be good" or am I pushing my luck?

Chas

[Inland RV Center, In]

Chas.

"ANY" movement at the frame/ floor seam at the rear, is not good news.

The greater the movement, the greater the problem.

A 1/4 inch movement sets you up for rotten plywood, along with when you tow, that seam will move everytime the trailer hits the smallest of bumps, which increases the problem.

I would suggest you test the plywood now, with an ice pick, to determine the condition of the plywood.

The sooner you address the issue and take corrective measures, the less it will cost.

Andy

[overlander76]

Andy and anyone else,

I have a few questions for you about this topic. Thanks in advance for your time in responding to my questions. Ive read a few of these threads on rear end seperation and these questions come to mind. When I bounce on the floor in my bathroom, it seems to give, but it feels like the front end is coming off the ground. I don't have anything weird going on with a crumple behind the wheels or any rivets missing outside or anything like that. I am still worried about this as it seems to trash the Airstream (I saw your picture on the topic where the entire rear end was gone) Why does rear end seperation happen? Isn't there a set of frame rails that go all the way to the end of the Airstream? Was this a defect? Does anything cause this becides running gear unbalanced? Water rotting the plywood? Is there a way to reinforce it? I have a 76 overlander rear bath (27').

Thanks
Brian

[j54mark]

What is called tail droop, rear end sag, rear end separation, and some names not suitable for print is essentially this: the frame has parted from the body/shell unit.

One of the things that confuses a lot of people is that the body/shell of an Airstream are a unit. This "monocoque" construction is then attached to the frame. The frame does not hold up the body, rather to the contrary, the body holds up the frame! This is why the frame will "droop" if the attachments fail. The plywood floor need not be rotted when failure occurs, but once it happens water will begin to seep in through the bumper area and rot the plywood from the bottom up.

The point of attachment is the "C" or "U" (depending upon how you look at it) shaped channel that runs around the perimeter of the body, attaching the shell to the floor. The are several reasons why failure occurs, depending upon who you ask:

1. Unbalance running gear sets up vibrations which are amplified by the moment arm from the axles back to the rear of the coach. This distance becomes progessively longer as the size of the trailer gets larger, making failure more common on 30' models than on 19'.

2. The addition of grey water holding tanks to rear bath versions without corresponding structural improvements. Support for this theory comes from the availability of a factory supplied frame strengthing kit. The weakness of this theory is that it is sometimes seen in side bath units, although not often.

3. Beatrice Foods could not be bothered with petty details like their trailers falling apart.

4. Using the bumper for a support for spare tires, bike racks, generator boxes, or storage compartments created more stress on the frame than it was designed to handle. This is closely related to choices "1" and "2" above.

5. The Nixon/Ford years. Hey, for some people that explains everything.

You can choose any of the above, or any combination. I am sure Andy will chime in and straighten out where I have gone astray.

Mark

[flamingo-kid1]

DON'T do it! You really need to SEE the unit. Maybe it would be worth driving out OR taking a $99.00 flight!!!***
We just got OUT of a disaster on Ebay. (not the same seller) The guy told me no leaks and the butt was ready to fall on the ground. We cancelled the deal and the guy was being crappy.. although we haven't heard from him for awhile now. *** Do a study on which years are the best. *** We are new to the Club and have purchased a 1967 Ambassador from a WONDERFUL lady close to our home location. We're taking her out for the first weekend tomorrow night. GOOD LUCK in your hunt !!!

[Chas]

Originally posted by Inland RV Center, In
Chas.

I would suggest you test the plywood now, with an ice pick, to determine the condition of the plywood.

Andy

Andy,

I do have some rotted plywood at the rear. It leaked around there when i first got it but I have since fixed the leak. I can see where it is gone by opening the rear compartment door where the dump valves are, probably all of it beneath the rear wall C-channel and a few inches towards the trailer. I think it was from either a leaky rear window, thru the bumper seam or maybe the taillights. I have figured on having to replace it at some point but figured I would get some enjoyment out it for a year or so before I commence a major repair job which I am sure it will be. What would be easier, repairing it from the top or from underneath? I don't mind seaming in the last foot or so, anything other than tearing the bath interior out, right?

Chas

[sladew]

My wife and I just purchased a 1978 31' International LY. It has the rear bath. There is no rear sag in the unit presently. Should I be proactive and strenthen the rear? If so, what is involved? Is it possible for a do it yourselfer or should a cerified RV shop complete the modofications?

Thanks,

Slade Weaver

[DPeakMD]

SladeW--I think you should be proactive and address it before there is a problem. If you're handy, the repair is well documented. There's a PDF file of the Airstream Factory Service Bulletin that is on Tom Patterson's Website

Our '72 31' had BOTH problems of:
1. Frame sag-- this is simply a problem caused by (insert a multitude of debateable causes) resulting in a bend to occurring near the axles which affects of the entire rear half of the trailer. One of the ways to assess this is by the tell-tale buckle along the sides near the wheelwells. It is fixed by installing a "fish plate" around the frame near the axles. The axles have to be dropped in order to do this. The Airstream Factory in Jackson Center, OH did ours and they did a good job. I have heard of others having this done at reputable Airstream dealers and even some fixed by backyard welders! Use your own judgement there.

2. Rear-end separaton: Our rig's got this too! We all know the wonderful monocoque system of the aluminum shell is designed to be somewhat self-supporting. The frame ideally would be as well. But as above, tends to let gravity take over the rear end! This results in the shell and the rear bumper/hose carrier/frame parting ways. The two will move indepently of each other. Eventually a gap may develop. The gap, if unsealed, will allow water intrusion. This rusts the bolts that hold the shell to the rear frame by sandwiching the floor in a C-channel along the lower edge. The bolts rust out over time. Water will also eventually rot the wood and weaken the area further. The way to assess for this is to look for movement of the rear bumper/frame relative to the shell. You should check for this by bouncing on the rear bumper. That strip of caulk that seals the area directly in front of the rear hose carrier is KEY. Keep that area impenetrable to water and you'll save yourself heartache. However, if the shell and frame have become disattached, you'll probably need to have them joined back together as in the PDF above...

Just look at your rig carefully for the tell-tale signs described. If you don't see a problem and follow the precautions advised by many in other posts about attention to weight in rear, traveling with tanks empty, balancing wheels, drive slower, etc--you may never have to fix anything!

Happy Airstreaming!!!

Pic of rear end gap, stripped of old caulking and awaiting new...

[uwe]

Not to confuse issues, but my trailer does have a buckle in front of the streetside wheel well, but there is absolutely no separation going on, and no droop. I had Andy at InladRV inspect my frame and axles a while back, and it's all in good solid condition. ( Aside from my completely worn out axles) Andy says some trailers just have these buckles, without there being a structural problem. Flex and years of use together with degrading axles and shocks all do their part. I saw numerous trailers since with slight buckles in the aluminum, and others that were completely straight. My guess is that the buckle is caused by the multiple compound curve in this area. Later trailers had a more substantial wheel surround molding, possibly to alleviate these buckles.

[overlander76]

I would really love someone to give me thier opinion of my Airstream in person! If any of you are on your way to Estes Park Colorado, you are invited to stop in and have a cold one on your way!

[DPeakMD]

I wish I could be there right now OL76!!! I bet it's a lot cooler there than here in Indiana...

You might want to check and see, but I think there's a Vintage Airstream Club rally in your state sometime soon. It'll be on www.airstream.net.

You could probably make arrangements to attend, or maybe just stop by and chat with folks.

The Vintage Club members are a great group. It's the primary reason we belong to WBCCI.

Good luck!

[Inland RV Center, In]

There seems to be some confusion about the rear end separtion and the frame kit.

Installing the frame kit at the axles, does not and will not, cure nor prevent rear end sepaartion.

A frame buckle is an entirely different issue from frame or rear end separation.

Andy