Looking for experience with waterproofing a cap/bed

Friends,
My daughter plans to take the 1st gen on a road trip, and we're going to build out a bed frame situation for her in the back. Have an old camper shell ("Range Rider" brand) that is handy, but has never been water tight even with careful application of the rubber gasket and butyl tape at the corners near the cab.
I'm really hoping to seal it up as best I can; looking for anyone's practical experience.
So far, I've removed the drop in bed liner and cleaned it and the bed. Removed the shell, shell windows and back window. Cleaned the hell out of everything. Pics below for fun.
Before disassembly, put some paper towels around the inside during a rainstorm to identify leaky spots. Most were near the bed corners closest to the cab; some at window seams.

I plan to:
--replace broken screens
--apply silicone to the window seals before reinstalling them
--use rubber gaskets at the tailgate/bed interface

Questions:
--do I try to apply silicone or auto seam sealer to the vertical truck bed seams nearest the cab?
--do I put the drop in bed liner back in or leave it out? it steals a bit of space on the interior, and I'm not sure it helps much with the water issue. it also creates a sealing problem at the corners of the bed nearest the cab since it goes *over* the bed adjacent the cab but tucks *under* the side bed rails.

Thanks for any inputs!
JV

 

Looks like the cap has been cleaned along the bed rail area. Take the extra day or two and order then apply this - it's the best seal I've found for the cap. Much better than that silly foam tape. Follow the included instructions when applying.

$29 ESI Super Cap Seal 20 FT (1 1/2" Width x 1/2" Height x 20' Length) EPDM Rubber for Caps 200 lbs or less

https://www.amazon.com/gp/product/B00NCC0SY6/

 

I'd also reccomend some putty. They sell putty you can put in the corners to help it seal. The trick is laying the gasket in the corners so it lays flat without cutting it.

 

funny, this is the exact one I've used before (and have bought again to apply when I put the cap back on).

 

I didn't think you could do the corners without cutting the gasket. The instructions say to cut a triangle out of the gasket to allow it to make the 90 degree turn and remain "intact." If you have another technique, I'd love to see pics.

 

That cut is usually how water gets in around the seam. Some of the seals like a heat gun. Sometimes I'll start to bend it then make partial relief cuts not all the way through but just enough to let it curve. This isn't the exact putty I used but something along the lines of this. Id put it at the ends and corners or anywhere you have water leaking.

$11 IDEAL Electrical 31-601 Duct Seal, 1 lb. Block

https://www.amazon.com/dp/B003MZK122/

 

If she's going to sleep in the back of the truck, the only advise I can give you is to make a raised bed. That way her sleeping area should stay dry even if it leaks a small amount.

 

FWIW, I’ve followed the instructions when installing the seal (slight cuts). No issues to report with water intrusion.

In the end, every cap leaks. It’s a matter of how much and how often that matter. A platform is a must if sleeping back there.

 

100%. Building a platform is on the list. Want to minimize risk of plywood getting wet and disintegrating....

 

I've lived in the back of a Toyota for months on end. Platform is key because it lets' you store all your gear underneath and out of the way (and out of sight).

Does any water leakage end up under the bedliner on in it? If it's under it, I'd lean it in. But if it holds the water skip it, or drill holes to let the water out.

I never thought to seam seal the front corners of the bed. Not a bad idea. My cap leaks at the rear window by tailgate. Cannot figure out exactly the issue.

You might also look for a locking tailgate latch. There is one make available but I don't know how good it is. I'm planning to make some locks on the inside of the tailgate so the tailgate cannot be opened even if the cap window is closed.

good luck--

 

The front corners of the bed at the top of the rail where the seams are is usually where most of the water will get in. Sometimes there is a slight difference in the level of the front rail to the side rails. Get some butyl tape and pack that area to make it as level as you can.

 

Stain and seal the bottoms and corners of the plywood and you'll be fine no matter what happens.

Like others have said, the foam tape on top of the bed rails is not perfect so you're already miles ahead with that ESI Super Cap Seal (plus window seals as you mentioned). I also put silicone in the corners of the bed near the cab - worked for me, but not sure if others think that's a bad idea in the long term. Rubber gaskets at the tailgate are nice to have to keep dust out, but I found that was never where water entered if you're running short on time before your trip.

 

JV==>

the camper's side glass......VERY similar to RV glass
this vid kinda long but this is how reputable RV shops seal glass
FF to min 30
after installing butyl tape(kinda like a putty strip)
this is where you place 2 lines of painter's tape on outside of window, leaving small gap
this prevents the sealant spreading everywhere

https://youtu.be/gdCJcYReegI?si=Kp9DIMoRQRKprh8P

here is a shorter vid
but this couple did not seal outside with this painter's tape trick

https://youtu.be/7Aka0aUGUE0?si=JJdlsL5j25Tdc2TN

hope this help you!!