suspension, axles

[les palmer]

hi i just bought my first airstream it is a 1970 31ft ambasador.i noticed it sits lower on the right hand side,about 1.5 inches.can anybody give me some advice on this? i have read quite a bit about axel replacing on older airstreams,how do you know when axel replacement is necessary?i would appreciate any info on this subject.this is my first thread, looking forward to hearing from anyone regarding this subject.

[Anon]

Howdy Les!
That is a great first post!
Your axle seems like it is in need of replacement. You will find a lot of information by using the "Search" feature located on the forums toolbar located just below the "Tabs" that start with "portal". "forums", "photos", etc...
To see if your axle needs to be replaced. Look at the "dog bone" that your spindle, backing plate and brakes are mounted to. This "dog bone" should be pointing down, (toward the ground), a little. If not then it is a safe bet to replace the axle.
Also, look to see if any of the wheel, or wheel cover, is hidden under the side of the trailer. If it is, then you probably need to replace the axle.
I would highly recommend you use a local axle shop that deals with Al-Ko or Dexter. These are the largest manufacturers of torsion axles. Dexter has thousands of dealers in the U.S. and Canada, so if you have a problem, (which is highly doubtful), you will be able to easily get service.
You can also go with the "OEM" replacement axle. This is an expensive alternative.
Also, keep in mind, if you are going to attempt the replacement yourself, that your axles have been bolted to the trailer for 37 years. Those bolts are going to fight you when you try to take them out.

[les palmer]

thanks for the feedback,i also noticed that the rear bumper can be moved a bit by pushing down on it,the bodywork has been in contact with the bumper.is this a serious frame problem?i guess i should have checked it out better before buying.love the trailer hope it will not cost too much to fix.

[Anon]

Les,
That sounds like the "rear-end sag" that the early 70's models over 25' are prone to have heppen.
My father's '73 31 footer suffered this fate. My father had owned this trailer since it was new, up until his death in 1986. My brother-in-law has owned it since then. This is nice because the entire history of the trailer is known.
If you notice your frame getting lower than the body then you have some separation going on. My brother-in-law took the 73 to Jackson Center ten years or more ago. The "job" they did was not the "top-notch" job you would expect from an elite trailer manufacturer. In all honesty, it sucked. He took it back and they said they would do it again but that there was no warranty left on the original repair. He had them do it again. This time it held for even less time.
This time he and I tore into it. What we found was disturbing considering he spent a lot of money with Airstream. They had attached the new braces to rusted metal on the frame. It was slip-shod at best. I have seen better work done at local fly-by-night local repair shops!
If you think you may have frame sag then get it taken care of ASAP. It will only get worse.

[overlander63]

Originally Posted by les palmer

thanks for the feedback,i also noticed that the rear bumper can be moved a bit by pushing down on it,the bodywork has been in contact with the bumper.is this a serious frame problem?i guess i should have checked it out better before buying.love the trailer hope it will not cost too much to fix.

Strangely enough, I am working on that exact problem on our Sovereign. It turns out the last inch or two of the wooden floor, all the way in the back, has deteriorated (nice term for "rotted") to where it no longer supports the frame. An Airstream is slightly different from most trailers, in that the shell and floor support the frame, rather than the other way around. I will be posting pictures of the completion of the repair later this evening. It's pretty invoilved, but can be done without tearing apart the entire trailer.
About the axles, there are several choices for a replacement, some better than others. You can get a direct-fit "drop-in" pair of axles from Henschen, and do it yourself, and have OEM stuff, which is good. You can also use Dexter or AlKo, and have the axles professionally installed for roughly the same price. They are reasonably close as far as quality, the main difference is that the aftermarket axles may have to be slightly altered to ensure a proper fit.

[Inland RV Center, In]

Originally Posted by les palmer

thanks for the feedback,i also noticed that the rear bumper can be moved a bit by pushing down on it,the bodywork has been in contact with the bumper.is this a serious frame problem?i guess i should have checked it out better before buying.love the trailer hope it will not cost too much to fix.

Rear end sag is very different from rear end seaparation.

Rear end sag, is caused by a bent frame. The bumper area is still ok.

Rear end separation, is a different story. That's when the bumper will move up and down with the simple push of the hand. Try standing on the bumper and jumping up and down. That bumper movement could be an inch or two.

There are many posts as to what must be done to properly repair rearend separation, in this forums.

Under "NO" conditions, get involved with the elephant ear rear end separation repair.

At best it's temporary, and will only allow the other damage to continue.

If you cannot repair the separation yourself, then take the coach to a dealer, that can and has repaired the rear end separations.

If that dealer even mentions "elephant ear" repairs, don't bother disconnecting the trailer. Leave that dealers lot, "quickly."

Rear end separation, "when properly repaired," can cost anywhere from not quite a thousand dollars to over $3000.00 dollars, depending on how much of the floor must be replaced, frame damage, etc.

There is no "quick cheap fix" for rear end separation.

Rear end sag, is caused by the frame bending at the axle area.

Rear end separation, is caused by having a weight added to the bumper, and/or lack of proper running gear balance.

It is not caused by a full gray or black water tank, as some owners may indicate.

Andy

[dwightdi]

If you are a structual engineer and examine the frame closely you can tell whether the frame sag is due to abusive usage or an out of balance running gear. If there is a crack in the frame behind the rear mounting point of the axle, it may be a fatique failure due to out of balance. You will only be sure after you cut out the crack and examin the fracture surface for the presence of "beach marks". If there are no beach marks then it a singular failure from abuse exceeding the tensil strength of the steel originating from the top of the frame and extending downwards. From the outside the fatique crack and the abuse crack will look the same. There is another form of the rear end sag in which the trailer has seen abuse which did not exceed the tensil strength of the mild steel used to make the frames but did exceed its yield point. This is characteristed by a bend in the frame at the same location but no signs of cracking. The original 4 inch deep design just did not take into account the abuse the customers put these trailers through. Early failures were covered by the factory warrentee and many were "fixed" with what Betrice thought was a cost effective cure. Their answer was the elephant ear fix along with the frame stiffener fish plates attached to the axle mounting plate. The elephant ear fix increased the amount of bolts to the shell, so more of the load from the rear tanks would be shifted to the shell. It helps but is not the perfect solution. The frame stiffener increased the strength of the frame in the areas it covered but did not completely make the trailer impurvious to abuse. The real answer was to go to the 5 inch frame which came some years later. I have never seen frame bending or frame fatique failures on a 5 inch frame no matter how baddly the customer treated the trailer.

[TomW]

Originally Posted by dwightdi

If you are a structual engineer and examine the frame closely you can tell ...

Well, most of the people on this forum are not structural engineers, Dwight. Other than you and Jim Golden, I don't recall anyone else with advertised expertise with beach marks.

Would you have a picture or two that would help everyone understand the situation?

Thanks,
Tom

[Ganglin]

So - if you have a 71 as in our case - it has a 5" frame measured at the bumper connection - and when you stand on the bumper and bounce you get maybe an eighth of an inch movement - there should be no concern??

[Inland RV Center, In]

Originally Posted by Ganglin

So - if you have a 71 as in our case - it has a 5" frame measured at the bumper connection - and when you stand on the bumper and bounce you get maybe an eighth of an inch movement - there should be no concern??

Any movement is a warning that the separation problem has started, no matter how small.

Andy

[les palmer]

thanks for the info,what type of plywood do you replace the floor with?is there a type of plywood that will not rot?and if so what is it called and where do you get it.i would appreciate any info, thanks

[PizzaChop]

Les,

I used AdvanTech on my Overlander, and just regular 3/4" plywood on my '73 Sovereign. I think the AdvanTech is better in that it has much more glue in it.

Either will rot eventually with prolonged exposure to moisture. (Of course your frame will rust and disintegrate as well if exposed to the same)

Replacement is more fun than a barrel of monkeys as it requires complete removal of all rear bath components, which usually requires disassembly of the bedroom as well.

There will probably be some frame restoration involved as well, depending on how long the condition has been allowed to progress.

This is generally not the kind of news most new Airstream owners like to hear.

The culprit is moisture which either comes from the inside (bathroom fixtures, water heater, etc.) or the outside (rear beltline seal, trunk door, window frame leaks, tail light assembly).

If ignored, it will eventually lead to separation, frame damage, sag, and utimately will damage the shell.

While the original frame dimensions may seem "light", it was designed to work with the shell and floor in a monocoque design which will last forever providing all components retain their structural integrity. Once the plywood floor rots at the critical rear sandwich joint (shell/floor/frame), the "play" created by the rotted plywood will create havoc with your frame, as it no longer receives support from the shell.

I learned a long time ago this eternal truth: There are two types of old Airstreams, those with rear floor rot/separation issues, and those with rear floor rot/separation issues which have been repaired. (There is a 3rd category of those which have been rigorously maintained their entire life, and therefore do not fall in the above two categories. They are very difficult to find and tend to be a bit more expensive than the usual garden variety '70s era unit.)