All the aluminum you can’t see….
We think the axle on Tess is original, because we have no paperwork to indicate otherwise, and all the previous owners kept all the receipts for everything else. And while everything seems to be ok with it, we know that the life expectancy of a Dexter Torsion Axle is about 25-30 years, and given the 58 years Tess had on her at the time (2023) we decided she was due for an axle swap. We made our order through Colin Hyde Trailer Restorations, who came highly recommended on Airforums. The office is busy and we’ve heard tales that he can be a little slow in responding but our experience was quick and painless. He asked all the questions needed about the trailer year and width and three weeks later our axle arrived. Be aware you’ll probably need a liftgate truck to have it delivered to your home- it is too heavy to set down. We used our tractor with forks, so that worked for us.
And since we were there, we decided to replace the aluminum underbelly. After 58 years the aluminum had become quite worn and corroded- especially in the areas where it had contact with the copper gas lines. With the axle out of the way I could relace that section of aluminum fairly easily- with the axle in place it was very tight to work. It would also allow me to inspect the frame and add insulation. And, since I was there, replace any wiring or systems that needed to be replaced.
Airstream originally used one single sheet of aluminum on the underbelly. I didn’t see any really good way of doing that, but really I prefer the idea of doing it in sections anyway- if I need to make a repair later I can just remove the section that needs to be worked on. I’d already done the section of underbelly that formed the underneath of the gray tank, so I bought four more sheets of 20 gauge (.032 inch) aluminum- two to go from the gray tank area and past the axle (up to the step) and then two to go from there up to the front. I got mine from a local metal supplier, so no links for that- you can look one up in your area though.
I realized pretty quickly that mounting the aluminum to the narrow crossbars of the frame was going to be really tough- too much potential for missing the crossbar, not to mention weakening them with holes AND introducing more places for corrosion to happen. So I opted to buy some 1/8 aluminum flat bar and use pipe hangers to suspend them from the crossbars (running front to back). I did one down the center and then one on each side of the trailer. The pipe hangers go through the large holes in the crossmembers and then I riveted the flat bars to the pipe hangers. I wish I had better pictures but at the time there was no plan for a web page! Anyway, the result of doing this gave me two inches of flat bar to attached the underbelly to, and far more support of the underbelly- as many rivets as I wanted to install. I went about 6″ between rivets. I thought about sealing the overlapping sheets but opted to leave them unsealed but with a lot of rivets holding them together- this made it tight enough that no rodents can get inside, but enough for any water that might penetrate somehow to have a place to get out. I used the largest size rivets (1/2 ” width) available.
PRO TIP: Instead of trying to drill holes while laying on your back and hoping it all lines up, use these self tapping metal screws. They drive in quicker than a drill bit, hold the metal in place and leave a hole big enough for a rivet. I use them instead of drill bits for a lot of things- for one they are much cheaper than drill bits- once they no longer cut well you just get another one. But I was also able to quickly position the metal, have the screw hold it in place and then do a more final position and lock the metal into place. Then I’d use as many screws as I wanted for the rivets and have the metal all screwed up in place, nice and solid. Then one by one I’d remove a screw and replace it with a rivet. Trust me, there is no easier way to do this.
But I’ve jumped ahead here, mostly just to explain the process. Jumping back to removing the original underbelly, once I had the underbelly removed I was able to assess the frame. We were very lucky that there was only a light surface rust on some of the crossmembers and outriggers. I used steel wool and Rustoleum on them and was happy with the results. Even the original insulation was dry and intact, with no sign of rodent infestation at any point (yes, we were lucky) so I just added some basic fiberglass insulation since it was so poorly insulated from the factory. Some people prefer Rockwool, but I have no problems with fiberglass- once it is contained it has no significant outgassing. I personally would avoid spray foam insulation on the frame, it can trap moisture and lead to rust.
I also decided, since I was there, to replace the wire for the trailer lights from the 7 pin connector in the front to as far as I could get them in the back. The current configuration was a patchwork of a modern 7 pin connector wired into the old 1965 trailer harness which then went into the frame just behind the tongue and emerged underneath into a rats nest of wire in the underbelly. To me that was just unacceptable. So I bought the longest 7 pin cable I could find, ran that underneath the A frame f the trailer and then up through a grommet in the front banana peel, through the crossmembers to it’s stopping point, which is underneath our fridge unit. Given that our fridge is propane/110V it requires venting on both top and bottom. Originally the bottom vent was just wire with a screen mesh on top, but I replaced that with an aluminum louvered vent, again, so I could access things later if needed.
I terminated the 7 pin cord into a trailer junction box, then ran new color matched wire up under the fridge to the inside of the camper (again for accessibility) and under the davenport into the mechanical area of the bathroom, then to the lights- at least as far as i could go, since the wires end up in the exterior panels. Was it a lot of work? Yes it was. Was it worth it? If I have to make repairs in the future it will be- but in the meantime I have as close to new everything that I can have.
Again, since I was there and already running wire, I went ahead and replaced the trailer brake wire– and I’m glad I did since it had some cracking due to brittleness. I also replace the original breakaway switch (that did still work) with a new version.
With the insulation in, new wires run and underbelly installed, it was time to take on the intimidating task of installing the new axle. I’ve done a lot of mechanical work, so I wasn’t too worried, but I wanted to get it right. There are some differences between the old axles and the new- in particular the holes don’t line up and the shock mount faces the wrong direction. Neither is insurmountable though.
The holes are actually the easiest to deal with. Using a couple of jacks, get the axle positioned in place- measure from the tip of the tongue to the axle on each side and make sure they are the same distance so the trailer doesn’t pull to one direction and mark those positions. The find the center of the new holes that need to be drilled and mark those- take a punch or big nail and make a small dent at dead center, it will help you when drilling. You can use a drill bit but big ones are expensive and unwieldy. Use a step bit instead, it will work much better. You can get cheap ones but they are so handy in general that I’d spend a little more on at least decent quality ones like these.
The shock mounts were more of a pain- they actually face into the trailer so there were only two choices- cut them and re-weld to face outwards or to install the shocks before the axle, which means to replace the shocks in the future you’ll have to remove the axle to do it. My welder, and welding skills are not strong enough to that so i opted to install the shocks first. I’ve heard the shocks don’t really do much for the Airstream anyway, but if they put them on they must do something! Anyway, these shocks fit, in case you need them.
The next shock challenge was the pieces of metal that Airstream installed as bump stops- designed (I think) to prevent the axle from hitting the wheel well if the actual wheel fell off. Their positioning, as well as the different axle shock mount position, kept the shock from being able to fit where it needed to go. I couldn’t see a particularly good use for this setup, so with a reciprocating saw and a good carbide metal blade I cut it off and fit the shock into place.
So after the metal is cut, holes are drilled, bolts mounted the shocks tightend down, brakes connected and wheels installed we should be good to go…
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