• rebasgr8

Van Build #1: The Foundation

Updated: Jan 27

In any van build there's a lot of prep involved before adding any structures, and most important, is preventing leaks! For my van conversion, I wanted to make sure my van was primed, sealed and and leak free. This entailed creating a dam and rain guard, cleaning, priming, checking for leaks and sealing cracks, holes and spots of potential leakage. (This was all done after installing the Maxxair Roof Van. I didn't post about that as I wasn't involved in the install.)


Check for Leaks

With headlamp in place, I shut myself inside the van while my friend took a hose and sprayed from the roof and around the outside at various angles. Luckily, the only leaks we found were at the door locks and around the door seals on both the side slider door and rear doors.


Fix Door Seals and Holes

First to fix the leaking door seal. Using butyl, as recommended from the dealer, we removed the seal where it was leaking, applied butyl and sealed it back up. The leakage at the side lock was only coming in when we sprayed at a weird and unnatural angle, so we left it alone. Technically, the lock area could still leak if there was ever a hard rain coming in at that same angle. However, any rain would end up in the lowest cavities on either side of the van. In the ProMaster, I was told these are specifically designed to collect water build up, drained out through the back where there are openings to the outside. These cavities (the van moat) also contain the manufacturer's holes filled with rubber plugs that can be removed from the underside of the van for drainage purposes. For this reason, I will leave the moat alone when insulating the van.


To prevent future leaks, I searched for any holes that weren't part of the manufacturer's design. I did find a small 2 mm diameter hole in the very back which I sealed with silicone from the underside of the vehicle. Also, two of the rubber plugs in the lower moat area were missing. Rather than going through the hassle of finding new plugs, I sealed them from the inside with nickels and Dicor lap sealant. This is the same lap sealant used on the roof fan install.


To keep the door seals in good shape and prevent damaged and/or dried out seals, I applied Dielectric Silicone Grease to all the door seals. Well, I can say I "tried" to do this. As it turned out, it was too cold outside making it next to impossible to apply correctly. I have made a note to do this in the spring.


The side plastic trim panels on the ProMaster can be potential leak spots. Therefore, from the inside, I sealed around the pegs that hold the trim panels in place using silicone, only sealing the ones within my reach. Many people also seal around the row of lights on the roof at the front and the back of the vehicle. I have yet to do this but will most likely.


Finally, we checked and reinforced the seams on the roof and around the van, as needed. The idea was to prevent any future leaks that would be difficult to see until it's too late.


Create a Van Rain Guard Above Slider Door

Above the side slider doors, we created a rain guard using a 1" plastic corner protector and attached with 3M Automotive Moulding Tape. When cutting to size, just make sure it extends out past the width of the door on either side.


Clean & Prime the Van Floor

First I cleaned the entire van floor with a solution of water and ammonia to remove any grease or residue. Then, to prevent rust, we primed the van floor.


Create a Van Dam

At the back of the van, we created a dam using vinyl round moulding from Lowe's. Cut to fit and with side edges smoothed out, we attached and sealed it using caulking. Don't use the kitchen & bath kind as we did as I have since read that it can cause rust. Something like this marine sealant should work. This dam will prevent any water from entering the van. Later, it will be finished with trim so it will be flush with the van floor.



ProMaster Cowl Leaks

This leakage issue is only related to the ProMaster, and it's a biggy! As soon as I read about it, I opened my hood and found huge sheets of ice and pools of water. It can reap all kinds of havoc, including damage to the serpentine belt and electronics, not to mention causing the bolts on the manifold to rust! Apparently Dodge has known about the problem for years and has not corrected it. They also will not fix it under the warranty from what I've read. I will be working to fix these leaks using the advice found here: 7 Ways to Stop Cowl Leaks, but for starters, I applied electrical tape to the rubber seam along the base of the windshield and over the seams between the 2 parts of the cowl, sealing up the gaps that were apparent and allowing water under the hood. When it's dryer outside, I'll make this more permanent with black silicone, but for now, this will have to do. For the other cowl leaks, I may need some help! 😯


Extra Rain Protection

I ordered RV gutter moulding which I haven't installed yet. Many ProMaster owners are using it, so I'm going to do so, too. I'll make sure it goes above the back doors, above my aftermarket bunk windows when they are installed and possibly above the front windshield.


If you have questions about about any of the above, leave in the comments below.


Happy building.




#vanlife #vanconversion #preventingvanleaks #weatherproofingvan #cowlleaks #promastervanbuild #vanbuildguide #promasterleaks #vanweatherproofing


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