Broken rivets in front

[rluhr]

I'm posting this because I've run into three 1968 owners with this problem, counting myself.

The problem: there are two rows of rivets along the front of the trailer, of which many have broken. These rivets tie the exterior skin into a hidden steel plate. See first picture, of my 68 Caravel. Note that a couple of the rivets have black rings around them, indicating that they have broken loose and are rubbing the skin. (The black stuff is aluminum oxide.)

The steel plate can only be seen if you remove the interior skin. It is welded to the trailer frame under the very forward section of the floor. See second picture, from a 70's Argosy. The steel plate is in the very upper left corner of the picture (out of focus), and it is welded to the A-frame as it passes under the aluminum U-channel. You can also see some sort of steel stabilizer welded in there (the thing with the holes in it).

I've tried replacing the rivets with Olympics. They fail quickly, usually within a few hundred miles. Olympics apparently aren't strong enough to take the stress of this particular job. Other '68 owners have told me that they have encountered the same issue.

We recently removed the interior to take a look at the steel plate and see if it yielded any clues. The third picture shows the plate and the rivets in it.

Note that most of the rivets have been replaced with Olympics (by me). By looking at the broken stems under a microscope, we have determined that they are not being sheared off. They appear to fail simply because they aren't strong enough.

Of the remaining factory rivets, you can see a pretty sloppy job of riveting. One rivet is entirely flattened -- yet hasn't failed. Others are improperly bucked as well, yet still tight after 36 years.

(The rivet in the center that appears black is actually a cleco -- a sort of placeholder for a rivet. Disregard that one.)

We also looked at the stumps of the failed rivets, which were lying in the U-channel. So far, no "smoking gun" has appeared. They seem to have twisted and broken off, but I don't know why. From the stumps, they seem to have been bucked properly, more or less.

The plan is replace all the Olympics with bucked rivets made of hardened aluminum (from Aircraft Spruce). I will post an update after a thousand miles or so.

At this point, the only thing I can say definitively to fellow owners with this problem is that Olympics just won't cut the mustard in this specific application.

[wahoonc]

My 75 has a similar plate with sheared factory rivets, I attributed it to, rotted floor, poor PO maintainence, rough handling, and unbalanced running gear . That area of the trailer takes a real beating every bump, jar, twist, pot hole and expansion joint on our hiway system, and if you are using a heavier than normal tow vehicle or a super stout WD hitch, it probably contributes to the issue. The Oly's are a very soft rivet and not suited for that area at all, IMHO. I am still a little ways off of that repair, but was thinking that bucked rivets or SS bolts and nuts were about the only choice for that area.

Aaron

[Chuck]

Its from towing it with that big huge truck of yours!

(oh, wait: you don't have a big huge truck....hmmm...)

Seriously, though...that has been said here before by our favorite guru. too "stiff" of a ride, either from too heavy spring bars, too stiff a t.v. suspension, either or both. I would guess that perhaps an axle that has lost its "bounce" might contribute, as well.

what I don't understand is that if they're not "shearing"...then what else is happening to them? how else could they "break"?

[markdoane]

The original rivets in my '59 held up very well, although the bottom of the steel plate was very corroded. The plate was bolted to the first frame crossmember, not welded.

This trailer was never 'overhitched', in fact most of the miles on it were behind a Dodge station wagon.

Are you going to up-size to 5/32" hardened rivets?

I would think that aluminum rivets in a steel plate is a recipe for failure, regardless of the type of rivet. I would put the rivets in 'wet' with zinc molybdate.

[TomW]

Do you and the other '68 owners have tow vehicles with similar aerodynamic characteristics? I wonder if a wind tunnel test with your TV & Caravel would make sixties era Airstream engineers sit up straight.

Although I noticed no similar problem on my '67 Overlander, it has had a spare tire sitting in front of that panel it's entire life.

I think your current repair plan is the right thing to do. The only other thing I would question is the size of your weight distributing (spring) bars. If you can keep a secret, I hear there is going to be an article about those in the next issue of Airstream Life

Tom

[Pahaska]

In the early days of this forum, there was a thread that dealt with the steel plate and the problem of failing rivets. I remember that InlandAndy posted to it.

I don't remember anything other than it was discussed.

[rluhr]

Thanks for all the great replies.

Aaron: my Dad, an old engineer-type, wants to put in the SS bolts or screws too. He says he can make it a permanent repair. I've resisted this good suggestion only because I'd like the front end to look as original as possible. His counter-suggestion was to shave the screw heads until they looked like rivets.

Chuck, as you know the Honda Pilot we tow with has a pretty soft suspension, so we ruled suspension issues out right away. I don't *think* it's an axle issue, since we seem to pass the Inland RV tests, and nothing else in the trailer shows signs of abuse despite many miles of towing in the past year (10,000 or so).

I think it's significant that these are the ONLY rivets to fail in the entire trailer since we bought it. Perhaps this is an area of particularly concentrated stress, as Aaron suggests.

What I meant about the manner of breakage was that the original rivets all broke as if they became brittle and snapped off at the stem. The Olympics basically tore apart at the exterior (leg) portion. The stems of the Olympics remained intact. None of the original or replacement rivets showed signed of external stress (e.g., the skin chafing the sides until they were "cut" off).

Don, we are going with the same size rivets. None of the failed rivets had to be drilled out, and the holes appear to be very close to original size. "Old engineer" Dad agrees with you that aluminum rivets shouldn't go in steel plates, but didn't think to make your suggestion.

Tom, the other 68 owners tow with more typical vehicles (i.e. Suburban, Econoline van). Our hitch is an Equal-i-zer sized for small trailers. And as far as the article in the magazine, well, don't believe everything you read online ...

[Over59]

Dear Richard.

Buy a new axel before the whole thing tears itself apart , and don't be cheap, get the full thing.. You put alot of miles on that AS. I believe the plate it to provide support in front of the water tank and behind the LPG tanks. Seems like a good idea to me. I think if you replace your axel you will find your rivets will be OK. Hope you got your ceiling light cover back on OK.

[Chuck]

there are plates front and back that hold the shell onto the frame. don't think the water tank has anything to do with it. My water tank is under the floor in the middle of the trailer, and there are still steel hold-down plates front and rear.

I'm wondering...do you really *need* the fancy hitch with such a small trailer? tounge weight is only 330lbs...would be an interesting experiment to put new olympics in, and drive around a bit w/o the wd bars, and see what happens. Or perhaps the hitch just needs to be loosened up a bit.

[rluhr]

Originally Posted by chuck

I'm wondering...do you really *need* the fancy hitch with such a small trailer? tounge weight is only 330lbs...would be an interesting experiment to put new olympics in, and drive around a bit w/o the wd bars, and see what happens. Or perhaps the hitch just needs to be loosened up a bit.

Well, you're probably right that we don't strictly need the w/d hitch. In fact, Honda actually recommends towing without weight distribution up to the full rated tongue weight of 450 lbs. But I've tried it without (briefly) and weight distribution definitely gives a better ride -- less squirrely in the front end. I also keep it on for the anti-sway properties.

To resolve this, I just went through some photos I took of the trailer right after we bought it. Guess what? The rivets in front were broken the day we took it home! (I didn't know that at the time, but the pictures clearly show the tell-tale black rings). So they broke under "previous management" -- and I'm just the sap who's trying to fix the problem...

[RivetED]

Judging by your photos alone, that appears to me to be an area of high torsional force. The flexing of the frame, the wind on the shell, & the sprung forces of your W/D & anti-sway hitch are all contribuiting factors. That's not to mention gravity. With these many different forces acting across a relatively small surface area perhaps total elimination of movement is not practical.

The actual area of resistive friction used to counter the torsion is only the combined contact area of the rivet heads. Buck rivets might have just enough 'slop' to allow this twisting to go on longer than a fully shored-up Olympic (cross-sectionally weaker than a single-shaft rivet). This is all conjecture of course, but it gives you another point of view from which to draw your own conclusions.

Personally, I would try the stainless-steel fastener solution. I don't know if Olympic makes a stainless rivet?, but maybe stainless 'buck' rivets are available. You have clear access. Good luck. -Ed

[TomW]

Originally Posted by RivetED

Judging by your photos alone... Good luck.

Or you might have just had bad original rivets in a high stress area

Tom

[uwe]

Are you sure the front section of flooring is in A1 shape? If not, then the shell is allowed to walk much more than usual.
My 1963 project had these rivets intact, despite a rotten floor. However, some of the rivet holes in the skin were oblong a bit.
A tell tale sign for floor/frame problems are buckles in the front skin panel.

[Over59]

Stress on the frame and skin is proportional to the condition of a unit's axel. I know people hate to look under there because it's going to cost them big bucks and a new axel or worse two, do not give a cosmetic improvement.
Anyone out there have this problem after replacing the axel?

[greg176]

I would open the holes up to 5/32 and use a universal hardened rivet.The head size is the same as the original rivet.The 5/32 will give you a little extra strength and you should open up the hole to 5/32 to get a good clean hole.I would also agree that you should check the condition of your axles.

[RivetED]

I just ran into this after a search on 'rivet failure'.

"A conservative method of predicting the fatigue life of a riveted joint is to extract nodal forces from an elastic finite element model with the rivets represented as beams, calculate the maximum sheet bearing stress using the quotient of highest load and rivet bearing area on the thinnest sheet, and then deriving the number of cycles to failure from the unnotched material S-N curve.

Any thoughts?"

Go Figure!!! I've got a few thoughts.......

[markdoane]

Originally Posted by greg176

I would open the holes up to 5/32 and use a universal hardened rivet.The head size is the same as the original rivet.The 5/32 will give you a little extra strength and you should open up the hole to 5/32 to get a good clean hole.

I agree. The old holes are work hardened from all the abuse, to the point where they may be part of the problem. Make sure the holes are straight and deburred, especially the steel plate.

[JohnG]

Greg176 is right on. Open the holes to 5/32 so you have nice clean holes and use hardened rivets. They do have the same size heads and you will have a stronger area once finished.

You must agree that something is causing this problem to reoccur. Actually I would check the balance of the tires and wheels first then look at the shocks and then the axels. If you suspect that anything is weak or faulty then replace it. Also check to make sure that your tracking is true between the axels. If they are off a little then a small vibration will transmit throughout the trailer. Once I have pretty well fixed everything in that area I would finish by making the necessay repair to the plate in front.

[rluhr]

Originally Posted by JohnG

You must agree that something is causing this problem to reoccur.

Well, let's be perfectly clear. The problem has only re-occurred on the Olympic rivets, which we all agree are much too soft for this application. The original rivets which had not failed as of a year ago, still have not failed.

To me, this suggests that there isn't a current hitch/axle/weight problem -- otherwise the rest of the factory-installed bucked rivets would be failing too. More likely, the failed rivets were originally put in poorly -- a very believable theory since the remaining factory rivets are pretty abominable. Looks like this one was bucked by a trainee on a Monday morning!

The suggestion to drill out to 5/32 is good one. But remember, all of the failed bucked (original) rivets have been replaced by Olympics twice, so all of them have been drilled out to 5/32 already! The concern now is whether those holes have been elongated further by the chafing of the Olympics.

I should repeat: I have checked the axle numerous times. It's fine, according to the standards set by Inland RV on their website. Not that I wouldn't like a new axle, but I'm not rushing out to spend $800 when I can try $1 worth of rivets first.

Tomorrow we will buck in the new rivets and tow 700 miles on a week-long trip. I'll report back later on any interesting problems or symptoms that crop up.

[JohnG]

Chances are you're correct on the reason for the Olympic Rivet failure. They are not nearly as strong as the hardened rivets. If the holes are too far gone for the 5/32 rivets to work then you don't have a choice and you will have to step up to the next size, 3/16. If that happens try this, buck in the ones that you need and then take a look at the front. Chances are that you won't readily notice the difference and you won't have to replace the oters too.
Make sure that your using hardened rivets in this application, that's the rivet with the small dimple in the center of the head.

If your axle is holding up the trailer where you can stand back and see a few inches of the rubber tire above the rim then chances are that it is ok. If the tires and wheels are in balance then you may need to replace your shocks. They can very easily be bad ad look fine. I have even placed high quality shocks on cars and trucks a time or two and even though they were new they were bad, so don't overlook them.

You might also think about using one of those balance rings that automatically balances a trie/wheel once it starts turning. I will look them up and post the link back here in a few. They are not too expensive and they do work really good. Plus they will give you longer tire wear.