Cubby Box Seal Failure

According to the builder's self promotion, they've been building "expedition trucks" for over ten years, and are therefore experts. If this is true, then our truck must be the very first of their builds to be driven off pavement, on dirt roads. An odd thing, don't you think?

Our reason for saying this is because our under body storage boxes (cubby boxes) didn't seal out dust infiltration at all. Which we discovered after travelling the 1500 kilometres of the unpaved Dempster Highway in the Canadian arctic. When we finally opened them up, we discovered that the interior, the Webasto boilers and all the kit inside, was covered in a healthy layer of dirt.

The seals the builder used, which are completely inappropriate, only have about 1/8" (3mm) of squish. Which, for a door that's almost four feet wide, isn't enough to make a perfect seal all around the perimeter. You see, we're talking about a fabricated aluminum door that has a welded joint along the bottom edge. Welding that joint as they did imparts distortion into the length of that edge causing it to distort. The length is no longer straight.

The other contributing factor is the way they hung the door on the box. They welded the hinges on, both to the box, and to the door itself. So there is no adjustment on the door at one end to try and get the 1/8" seal to work properly. And of course there's the box itself, and the double bend and welding that creates the lip onto which the seal is installed. With all those factors playing against one another, there's virtually no way the box would ever seal. That's why automotive seal manufacturers make so many varieties of seals.

We know quite a bit about sealing boxes, having built so many over the years for the laboratory area. Seal choices are enormous, and easily obtainable. So why this so-called expedition truck "expert" couldn't find them is beyond us. You don't have to look any further than your own automobile door or trunk to see how things work.

There's a great comparison between using a correct seal versus an incorrect seal right on our own truck. When we built the motorcycle lift, we included a large storage box on the lift platform. It has two doors that are each almost four feet long, and those doors sit down on rubber seals that we installed on the box side of the opening. You can look at the photos below and decide for yourself which is the right seal and which one is wrong. Both boxes were photographed at the same time, on the same trip.

One can’t help but wonder. If a customer can make a box that seals perfectly against dust and moister infiltration, why then can't the builder?