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co_skier · 11-05-2005, 08:08 PM

Has anyone heard of an issue with rear bath 70's 31 footers sagging? We are buying a 77 31 foot model and had someone tell us that it would need a "fix" because the rear bath 70's model sag due to the weight of the bath and water tanks.

dwightdi · 11-05-2005, 08:22 PM

I bought one before I knew of the problem. I did a cheap fix but it is continuing to fail. There is a factory mod which helps. You can easily identify if it has been installed because they cut away at the back by the access door and then install bolts from the body to the frame and cover over the access cuts with aluminum. The oldtimers call them elephant ears. There is also a reinforcing plate installed on the web that sticks down between the wheels and strengthens the frame at that location. If you sight down that web from the front or rear and it is wavey (not straight) then frame bending has already started to ocurr. The fix costs about $2500 nowdays. I do not think I could recommend you buy this unit unless the fix has been installed or you are not going to use the unit for much over the road usage.

Janssvt · 11-06-2005, 07:50 PM

Yes, there was an issue with rear baths and the frame sagging. We had a 79 that we had the frame re-inforced at a place here in Houston that does Airstream repairs. They put sleeves on the frame above the wheels. We were tol that the frame had just started to stretch. We have seen some with the repair that has the"elephant" ears also. Something to look for is the gap below the trim and the bumper in the rear, there shouldn't be any, and buckling over the wheels in the main sheet of skin.

wahoonc · 11-06-2005, 08:01 PM

Quickest way to check for rear end sag is to step up on the bumper...if there is any appreciabale movement between the bumper and body you most likely have some seperation/sag. FWIW there are two seperate issues at work here. Weak frames and rear end rot. The weak frame repair is fairly straight forward, it requires a reinforcing plate at the axle area, the last time I checked the kit was about $250 plus the install cost. Rear end seperation is a seperate issue and the fix can include the "elephant ears" or in a case like mine, the repair will be affected from the inside so no "ears" will be visible. If you look down the sides of the trailer you will see obvious signs of a bend or bubble just behind the wheels if there are frame issues. They can be repaired...also avoid towing with the tanks full.

Aaron

StingrayL82 · 11-06-2005, 09:57 PM

This is one time when I'm glad I don't have a grey tank....

Frederic

wahoonc · 11-07-2005, 04:25 AM

I am going to add this here, this is a pdf copy of AS service bulletin #146 dealing with rear sag and repairs. The "elephant ear" repair if you will. There are other methods but this one was effected by Airstream Dealers back in the 70's.

Aaron

StingrayL82 · 11-07-2005, 01:33 PM

Aaron,

I was always led to believe that the rear sag was caused by the extra weight of having a grey tank and no engineering compensation by Airstream, but the Bulletin shows that the late 60's and newer trailers have the problem....what WAS the cause for rear end sag, if it wasn't the grey tank?

Frederic

tphan · 11-07-2005, 06:52 PM

frederic- I believe it is caused by a combination of too much weight and length that is cantilevered out there, not strong enough main frame members for that weight, and water getting into the area of floor directly around the rear, curved C-channel and rusting out the bolts that hold the whole sandwich together, allowing it to droop, letting even more rain water in, rotting it more, etc. Prevention does indeed seem to be the key, as in keeping that area well sealed on the exterior, and not allowing interior plumbing leaks to go unchecked for years. They advise not going down the road with a full black-water tank, that is a lot of extra weight sloshing around at the very back end of the coach, doing it no good. Also it is advisable to set up stabilizing jacks under the rear end when camped (front end too) so it is not overly stressed by the weight of all family members back there. Again, many threads on this. -tim

dwightdi · 11-07-2005, 07:10 PM

The size of the frame did not change much from the 60's till the mid 80's and they added alot of features, length and weight along the way. The body of the Airstream is supposed to add rigidity to the frame but the bolts they used did not have enough bearing area to do the job without bending the C channel. That is why the elephant ear fix was instituted early on. That was before they even knew they had a rust problem. Then (67)they started making 31 footers. More problems. Then ('75)they put grey water tanks in the back. More problems. Then they issued the frame strengther web plate fix.

If you are doing back country (Mexico, Canada(some parts), or gravel roads) I do not think you really want a 31 footer with a rear bath. About 1985 they went from a 4 inch box channel frame to a 5 inch frame when they came out with the 34 footer. Most frame problems stopped after that but I still hear of some shell to frame separation even now when they take them deep into Mexico. On one caravan last year, they had to hold the shell onto the frame by putting a large cargo strap around around the unit to get it back to the US. If you want to here the whole story talk with Jim Matavich who was the mechanic on the caravan. I will supply his email if you email me.

wahoonc · 11-07-2005, 07:25 PM

Quote:

Originally Posted by StingrayL82

Aaron,

I was always led to believe that the rear sag was caused by the extra weight of having a grey tank and no engineering compensation by Airstream, but the Bulletin shows that the late 60's and newer trailers have the problem....what WAS the cause for rear end sag, if it wasn't the grey tank?

Frederic

Frederic,
Mutliple causes...unbalanced running gear, poor caulking maitenance, driving long distances with the holding tanks full, poor engineering...FWIW the battery is behind the axle on the 70's vintage units, not a swift move in my opinion.

Aaron

dwightdi · 11-07-2005, 07:44 PM

75 31 footer has one or two batteries right up front by the A frame. Unbalance in running gear causes fatique failure and rupture of outriggers and welds as well as pop rivets but does not cause bending which is an overstressed condition caused by underengineering or overloaded by too much weight combined with rough roads which cause impact that may double the static load. (man that is a long sentance.) Old rubber axle that get hard makes it worse as does poor shocks which die after many years.

You did not really expect a unit that is 30 years old to be in good working order without spending a bunch of money on it, did you? Axles are worth $3,000 plus installation.

wahoonc · 11-07-2005, 07:54 PM

Quote:

Originally Posted by dwightdi

75 31 footer has one or two batteries right up front by the A frame.
You did not really expect a unit that is 30 years old to be in good working order without spending a bunch of money on it, did you? Axles are worth $3,000 plus installation.

Dwight,
That would be first on the battery location, mine is located curbside in a compartment under the shower. As far as the age, nope, I planned on at least some work. But an Airstream that has been properly cared for is always in much better shape than one that hasn't...kind of like a house...if things have been maintained they will be in much better shape.

Aaron