Broken rivets in front

[JohnG]

Ok they are called Centramatics and here is a link to them http://www.centramatic.com/ Look through their online catalog to find the ones you need, think they are the 300 series part #300-556 at $199 per pair.

[Inland RV Center, In]

There is no mistery as to "why" rivets shear in the front hold down plate.

We must take into consideration, that we are towing old trailers, with new type tow vehicles. That is to say, the old trailers, when towed with old cars (soft suspension systems) hold down plate rivet failures were rare.

More about this in the December issue of Airstream Life.

But today, it's a different story.

There are several things, today, that contibute to failure of rivets in the front hold down plate.

First is using a heavy duty tow vehicle, instead of a soft ride.

Second is using a hitch grossly over rated for the job intended.

Third, lack of proper running gear balance.

Any one of these will cause those rivets to shear. Couple two of them together, will make the rivets shear even faster. Couple all three, and you will shear them off like no tomorrow.

Next, olympic rivets in the front hold down plate are fine. "BUT" the secret is add more rivets to the plate. If you have two rows, make it 5 rows, or more. More rivets, the less the problem, up to elimination of the problem.

We have used the olympics for years, and if done correctly, the problem never returns.

Rich Luhr, in particular, add three to four "more" rows of rivets, and you will be fine. The olympics will do the job. Add vulkem sealer to the backside of each rivet head, before insertion.

For those suggesting "hard" rivets, they won't accomplish anything. Using soft rivets is fine.

The "key" is to beef up the hold down plate to shell attachment. Adding these extra rows of rivets, does the job.

However, if the hitch rating is excessive, if the tow vehicle is stiff and if you don't reasonably balance the running gear, you may still have a shearing problem, not nearly as much, but some.

Also Rich, we have repeated warned owners of the old small Airstream trailers of spindle failures on the axles. Back then, as we know it today, the spindles were way too small.

Couple that with heavy duty tow vehicles, over rated hitches, no running gear balance, and do it long enough, will cause the spindles to fatigue crack.
Of course when that happens, there is no warning. The trailer simply falls to one side, causing other damages as well.

We at this point, are receiving orders for at least two axles a month, because of spindle failures.

In fact we warned a very nice lady about it a long time ago. She took the trailer to two Airstream dealers, who both told her the axle is fine, and we are just trying to sell axles. Not true, in both cases.

We report the facts. You have to make the judgement call.

Andy

[JohnG]

Originally Posted by Inland RV Center, In

For those suggesting "hard" rivets, they won't accomplish anything. Using soft rivets is fine.

Andy,
The reason that I suggested using "Hardened Rivets" is because that is what Airstream used when they manufactured my 1975 Sovereign. I did buy my AS used, but the PO was the brother of the Original Owner. I have contacted him and he knows the history and has never had an major work done to the unit. So that being said then it stands to reason that AS placed hard rivets in that area. Every rivet in that area on mine has the tell-tell dimple on its head that says it is a hard rivet.
Besides all that I would think that the use of hardened rivets would almost be recommended as standard by AS and by you in that area since soft rivets only have a tensile strength of 16,000 PSI while hardened rivets have a tensile strength of 38,000 PSI. This would mean that the shear strength of the soft rivet would be about 55% - 60% less than that of the hardened rivet.
I know that if I were doing this repair I would certainly opt for use of the stronger hardened rivets. Your suggestion of using up to 5 rows of Olympic Rivets in this repair shows the need for added strength, but olympics don't even come into the picture of matching even the soft rivets in tensile strength if thier website is correct, it says they only have a tensile strength of 245 pounds. I assume they mean 245 PSI. http://www.boltproducts.com/marson/b...bulb-tite.html This is probably why they fail in this area.

[Inland RV Center, In]

John G

The real problem with the front holdown plate/front panel is inadequate number of rivets.

Installing hard rivets in place of the original rivets, won't stop anything.

If the rivets are hard enough so they don't shear, then the holes in the sheetmetal will enlarge, causing a greater problem.

Olympics work fine, if you increase the number of rivets by 300 percent, or so.

Taking out the front lounge and interior metal, just to use buck rivets, seems hard to justify.

Andy

[Wardinbb]

Originally Posted by 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?"

I've got two thoughts on this one. Nice find for a test method Ed, but most of us lack the lazer lab in our garage to run the test! Along the same lines, the solution is inherent to the problem; its metaphysical, where the distance permissable between the extremes of any particular capacity is limited! LOL.

Inland Andy's solution embraces this concept and his solution is "reinforce it", along with maintaining a well tuned rig (axils, hitch,wheel balancing, load distribution, tire pressure,etc.) As he has pointed out many times,ie, more elevator bolts for rear end seperation, more rivets in this front plate, even sealant at new rivets; make it stronger, beef it up. It is clear to me that the aspect of "value engineering" has not escaped the folks at AS. Just because their design calc's say the application will perform, doesn't mean it's an optimum solution. The impact of more bolts,rivets, outriggers, stringers, and whatever all add to unit and production costs. We've thus experienced various failures as a result of this sort of "minimalist" engineering and production assembly. It's just the way it is, so it goes and time tells all.

Ed

[till]

Reading this thread, has me thinking and sent me out side to take a look. Being only a year different and having the same rivit patern, I checked. I have poped rivets on the sides of the panel in question and there is floor rot on the sides in the front.

[Ken J]

If you look at the lower front, this is what happens when rivets pop, floor rots and too big a vehicle. I'm replacing the floor, will replace that panel and beef it up.

Ken

[Ken J]

BTW, before anyone asks - the frame is straight...........

[Inland RV Center, In]

Ken J.

When you replace that panel, use two panels of .032 or a single panel at least .050 or .063.

Also I would suggest that you double the rivets in the vertical stringer as well.



Till.

Someone has already replaced some of the rivets in the vertical stringers, with pop rivets.

That's a no-no. Could be your water leak as well.

Also add three rows of rivets to the hold down plate, and double the rivets in the vertical stringer.

That should stop the problem from returning, provided you are not violating one of the big three no-no's.

If you are, the extra rivets will still help more than you think.

Andy

[Ken J]

Andy

Wow, thats thick - but as I think of it a really good idea. Thanks!

Ken

[till]

Andy,
I have yet to do repair work yet. Every thing you see is all PO. I plan on replacing every pop or Olympic rivet with bucked ones were there should be a bucked one.

I can't wait till I get ready to tow this thing.......

[JohnG]

Originally Posted by Inland RV Center, In

John G

The real problem with the front holdown plate/front panel is inadequate number of rivets.

Installing hard rivets in place of the original rivets, won't stop anything.

If the rivets are hard enough so they don't shear, then the holes in the sheetmetal will enlarge, causing a greater problem.

Olympics work fine, if you increase the number of rivets by 300 percent, or so.

Taking out the front lounge and interior metal, just to use buck rivets, seems hard to justify.

Andy

Andy,
I agree that removing the inner panel just to use buck rivets would be hard to justify and in the case of someone not having their interior panels removed I would agree with using 300% more rivets and Olympic Rivets, but in Rluhr's case he does have the inner panel removed as seen in the photos in his post above and in that case I would always use the stronger rivet. It wouldn't hurt to add another row of rivets, but sionce they are solid rivets I wouldn't thin that he'd need to add any more than another row as in the case of using Olympic Rivets.

I think we got to comparing apples to oranges for a minute there.

I'm replacing the panel in front that wraps under the wing window and to the side and the new is .040 guage 2024-T3 replacing the old .032 guage piece of 2024-T3 aluminum. In this repair I can't jusify removing the inner panel either and I will be using Olympic Rivets and shaving them, but if the inner panel were off I would use soft buck rivets instead.

[rluhr]

Originally Posted by JohnG

in Rluhr's case he does have the inner panel removed as seen in the photos in his post above and in that case I would always use the stronger rivet.

You're right JohnG. I had already removed the dinette, water tank, and front interior panel before I posted the first time. It turned out that removing those items in the Caravel took less than half an hour.

Anyway, an update: I ordered rivets from Aircraft Spruce but they didn't arrive before the big trip to Acadia, so I put everything back together (taking the opportunity to improve a few items along the way), and put in new Olympics.

I returned nine days later, with about 1,000 new miles on the trailer, and three broken Olympic rivets. Then I removed everything again (in about 20 minutes, easier with practice) and we bucked in the new rivets. Within about four hours, start to finish, everything was done.

I used a little of the Gord's polish to remove the orange anodizing from the rivet heads and now it looks like factory. Unfortunately, I have only one relatively short trip planned between now and winterizing, so the real test won't occur until next spring. Still, it will be interesting to see if the solution works. If not, I may add another row or two as recommended by Andy.

[JohnG]

I will be interested to know if this holds up. I do think that it will do just fine since you only had 3 broken Olympic rivets and have now done a complete replacement with the bucked-in rivets. The harder rivet should do the job and you should not need to do any further repairs in that area. I'd almost bet on it!

[rluhr]

Well, here's the conclusions. First of all, I didn't get a chance to road test the new rivets. It was too close to the end of the season, and I ended up winterizing the trailer without having used it.

But in the past few weeks, suspecting a larger problem, we took it to GSM Vehicles in Plattsburgh NY (a new Airstream vintage specialist) and he found that the forward floor was pretty badly rotted (see pictures). There was also severe rot in the battery compartment area, much like Stef's Caravel.

The rot meant that the floor was not bound into the C-channel, which is absolutely critical for the aluminum monocoque structure to have strength. So the upshot is, no rivet alone would have solved this problem. The floor needs to be replaced, which GSM is now doing.

We're not at the "Full Monty" yet, but I think we are looking at about 1/2 the floor. The moral of the story is, if you are shearing rivets on a vintage trailer, you need to check out the floor.

After seeing so many vintage repairs on this forum, I have come to the conclusion that every unrestored vintage trailer has some rot in the floor --- you just may not know it yet!

-- RL

[Over59]

Very familiar indeed. The soon to be famous water-tank filler leak rot curse. Did you check the floor under the toilet. If that's gone you might as well do the . ........... I cann't bring myself to say it.

[Ken J]

Richard

I agree - and I've said many times - is that all vintage trailers probably need floor replacement. On my 58 the floor was rock solid, but the front panel had buckled - after tearing out the floor I found a little bit of rot just under the shell c channel - just enough to make it buckle - you could jump up and down in the trailer and see the skin buckle - now with a new floor it is rock solid.

Also just because the floor is solid does not mean its good - in my case my trailer looked like it had been over some pretty rough roads as the bolts had loosened from the floor - just around the bolts.

Ken

[59toaster]

Andy:

I have 59 that was rotten as rotten can be and not a single rivet in that plate has ever been replaced or failed.

The older coach I have I noticed the the front of the frame at that plate is closer together then the newer coached. Thank that might have helped and why people like Don and I did not see the problem even with rot problems?

[Over59]

Some of my 59 floor looked fine. When trying to take out the sheet metal screws holding the channel to the floor they just turned around in place. Rotted out around the screws and little else in spots. 45 years of condensation on those cool screws adds up. new screw will be into epoxy filled holes.

[Inland RV Center, In]

59toaster

Several things contribute, singularly or collectively, to the loss of rivets on the front plate,

1. Type of axles.
2. Lack of proper running gear balance.
3. Type of tow vehicle (soft or hard suspension).
4. Spacing between the A-frame as it joins the shell.
5. Road conditions.
6. Hitch rating. (Heavier duty torsion bars than needed).
7. How many rivets that hold the front plate to the shell.
8. Added weight to the A-frame (from loading or a spare tire or extra
batteries.

Adding extra rivets to the front plate, will reduce or stop future losses.

Olympic rivets work fine as replacements, when correctly installed. NO WASHER TYPE OLYMPICS.

Andy