Correcting Skin and Structural Damage Related to Leaks

[Steve Bryant]

I’m starting a new thread that’s an offshoot of discoveries related to discoveries made while diagnosing leak and floor rot problems on my 1991 34 Foot Limited trailer (see related thread). At first, my floor rot seemed mysterious and then I learned of problems that others have had with floor rot, rusted frames etc.


I knew that I had some damage on the rear radiused corners that indicated hard contact with the ground by some previous owner.

[Steve Bryant]

The back corners and caulking that was compromised were problems. But they were not the biggest, nor the only, issues. The left (street) side wall had a lot of leak damage.


The right (curb) side had very little leak damage.

[Steve Bryant]

Also, initially, I thought that the street street side had an internal doubler along the lower exterior skin panel and the curb side did not or at least they weren’t the same. Also confusing was that the curb side skin was installed with normal modified brazier head bucked rivets and many of the street side fasteners appeared to be blind rivets. At first, I thought that they were “Olympic” rivets. Actually at first I didn’t know what an Olympic rivet was, but I knew that they weren’t bucked rivets. It confused me that they appeared to be normal looking rivets on the exterior and appeared to be pulled/blind rivets on the interior. All of this was before had the insulation all pulled out and the belt line and rub rail moldings (more vocabulary words that I’ve come to know along this journey) had been removed.

Now that I’ve removed the belt line and rub rail moldings, done more research about fastener types and done more investigation; I’ve become a more educated (perhaps wiser) person about all of this. I want to show you what I’ve discovered and ask you to join me on the journey to repair this trailer in a durable fashion.

[Steve Bryant]

Here’s a picture from the inside of the curb side rivets. These are the factory 4/32” (AKA -4 diameter) modified brazier head rivets.


Now here’s an interior view of the street side rivets after most of the caulking has been removed.


Note in this shot how the lower body side skin is still in place but the aft edge (about two inches) had been cut off, an inter-skin barrier had been inserted (black plastic sheeting) and a new skin had been overlaid on top of the original lower skin. This new lower panel had also been slipped under the original upper skin. I’m sure that it was repaired in this way to try to eliminate pulling the street side sidewall and furniture/cabinets, etc. so that the rivets could be bucked.

[Steve Bryant]

Here’s my plan:

• Separate the monocoque structure from the frame aft of the rear axles to relieve the downward pulling force of the frame from the monocoque body shell. I’ll have to do this anyway to replace the floor in the rear.
• I’ll drill out the rivets from the leading edge of the street side rear shell that joins together the upper and lower segments about 26 inches back.

• That will release the internal curved stringer from the skin where the upper edge of the lower skin begins to diverge from the stringer. Then, I’ll flex the curved stringer upward until the top of it is tangent with the upper edge of the lower skin. Raising this stringer up will allow me to move the rivet line up and gain more edge distance (ED) on the top panel and still have a decent amount of ED on the lower skin. Note: I’ve just retired from a 35 year career with a general aviation manufacturer where ED infers edge distance from the fastener hole to the edge of the material being joined (in case your first thought regarding ED was related to a medical condition). I’ll be driving the bucked -5 (5/32”) diameter replacement modified brazier head rivets sold by Vintage Trailer Supply (VTS).

This picture shows the top edge of the lower section of the rear street side end cap corner.


The picture also shows a modified (bent with heat gun) stainless steel bristled brush used as step two in caulking removal. I apply heat with a heat gun (as required) to soften the caulking to allow the use of a putty knife or chisel to scrape off the bulk of the caulking. Then I continue to warm the caulking and use the stainless bristled brush to better clean the metal. If I’m going to re-caulk, I also use a product called Imperial Cleanwood with the brush and a rag to get the residue of the old caulk off to ensure good bonding of the new caulk.


By keeping the upper and lower edges attached to the street sidewall skin and riveted to each other in the back, the relationship of the upper and lower sheet metal will remain aligned to each other.

• Then, I’ll drill new holes for the -5 rivets from VTS that will penetrate the upper and lower skins plus the lower flange of the curved stringer. These holes will be slightly higher and horizontally/laterally in between the old holes. I’ll re-rivet the vacated holes to fill them and add some strength even though most are barely attached to the upper skin. All rivets (driven and blind) that I put back in will be installed “wet” with TremPro 635 caulking/sealant.
• Then I plan to drill out every other pop rivet on the street side so that the existing rivets with keep everything aligned as is (AKA maintain registration). I’ll drive the -5 rivets where I have the interior exposed and use blind “Q Style” 5/32” structural rivets from Hanson Rivet & Supply where I don’t have access with a bucking bar to drive rivets. I’m using the aluminum Q Style rivets with the aluminum mandrel (I’ve ordered two grip lengths, QAAD502 and QAAD504). These Q Style rivets made by Avdel will be installed “wet” as previously mentioned and the mandrel to rivet interface is self-sealing/watertight. They should fit under the beltline and rub rail moldings as well as the modified brazier head rivets and be more than adequate regarding structural strength. Once I’ve install the rivets previously mentioned, I’ll drill out and replace the remaining upper and lower row rivets that were skipped on the first round.
• Now, I’ll drill out every other Olympic rivet joining the aft edge of lower street side skin to rear end cap and re-rivet using driven (bucked) rivets. Once that’s done, I’ll do the same again with the remaining Olympic rivets that were left in place initially. I’ll probably do this on the forward end cap to the leading edge of the lower street side sheet metal. However, if there is no evidence of leaks in this area, I may leave the existing Olympic rivets in place there. Since the rear section is cantilevered and the front is not, the rear section is under more stress so the Olympics are probably more than adequate structurally.
• Then, I will straighten the creases and re-rivet the lower end caps to the floor extrusion.

[Steve Bryant]

Once I’m finished with this sheet metal work, I’ll return to the floor replacement portion of this journey which you can follow in my leak/floor rot thread mentioned in the first post referenced in this thread. I’ll be making additional posts to this thread (including pictures) as I go along over the next several weeks. I welcome your comments, observations and questions. Also, if you’re interested in looking at some more pictures of this whole process, look at my PhotoBucket repository on this topic.

[ROBERTSUNRUS]

Hi, Steve; You're doing a great job. I don't think I would ever want to go that deep into an Airstream.

[flygrrl]

Hi Steve, great job! Looks like that tank/water heater did a lot of the damage to the floor, condensation strikes again. No pan for the drippings, just the OSB sponge.
Keep up the good work, your baby will be perfect in no time!
Leonie

[Steve Bryant]

Robert and Leonie,
Thanks for your kind words. I didn't think that I'd ever have to repair something this major on my dream trailer...famous last words!!!

Leonie,
I don't actually think that the water heater leaks at all. It may and I'll pressure test it when I pull it out to repair the way the sidewall was installed with poprivets. Here's a picture of the leaks above the water heater during a rain shower.

[william Haym]

You might find it could be the toilet water valve leaking in toilet itself.
Ask me how I know!!
Yes, that where my water leak was.
The left rear part of the betroom carpet was soaked!!!

[Landshark]

This is really scary; now I'm afraid to even go out and look at our '86 34' Ltd. NOT LOL.

Vivian

[Steve Bryant]

Vivian,
About 70% of the problems that I'm having are due to the fact that the trailer was improperly repaired. There are still some design and construction quality issues that have caused problems. But these design and construction issues are not nearly so serious as the improper repair.

[Steve Bryant]

Ralph and I have made progress on riveting the upper and lower skins using the modified brazier head rivets from Vintage Trailer Supply. A number of holes were really elongated, but they should be structurally sound and water tight. We're injecting TremPro 635 in and around each hole before driving each rivet.


Once the rivets were driven (AKA, bucked), here’s what they looked like. Note: since these rivets will be covered up by the belt line molding and we want things to stay waterproof, we didn’t wipe off all of the TremPro. Also, the holes with the red permanent marker dots are where trim rivets will go back in. I’m planning to use TremPro on these too, when that time comes.


This is going to be a lot better than the former pop rivets for any number of reasons (structural and waterproof related to name a couple).

[PhilipKS]

Thanks for the documentation Steve. Looking good!

[Steve Bryant]

Thanks Phillip. I appreciate the encouraging words. Some of this repair business is sort of like pulling your own molars. As soon as you pull hard enough to make any progress, the pain gets so bad that you have to stop and have a period of recovery! Certainly not for the faint of heart!

Although, I will have to say that once you figure out how you're going to approach the repairs and formulate a plan, everything gets much easier. I'm not nearly through yet, but I'm through a lot of the worst. Doing the prep work for each phase is harder than doing the actual repair.

Steve

[Landshark]

Originally Posted by Steve Bryant

Vivian,
About 70% of the problems that I'm having are due to the fact that the trailer was improperly repaired. There are still some design and construction quality issues that have caused problems. But these design and construction issues are not nearly so serious as the improper repair.

Thanks, Steve. I think ours is OK because the corner with the slight buckle is at the head of a twin bed, and I have pulled up the mattress and supporting plywood sheet several times looking at the storage space under there. I think I would have noticed darkened, damaged, or watermarked plywood subflooring in that corner. At least I hope I would have. It's too heavy to do it by myself, so I'll have to wait until I can get my husband involved. Still a scary thought, though. Hope your repairs are going well.

Vivian

[Steve Bryant]

Vivian,
When you do get around to further investigation, you might want to stick an icepick into the wood sub-floor in several places. Assuming that you have carpet, you can stick the icepick right through the carpet and pad and it should not show at all. You need to stick the icepick into several areas so that you have a reference since the icepick may penetrate the subfloor (plywood/oriented strand board) to some degree and still be sound and intact.

Regards,

Steve