Leak prevention between cap and bed for 3-G Tacoma: Is There a "Best" way?

I've searched and read many threads on 3-G Tacos regarding water entering into the bed between the cap and the bed due to (faulty) design of the railcaps (especially at the front behind the cab). From what I've gathered, there have been some successes, but many non-successes, at making it "waterproof." At this point, I'm left understanding that it is either hit or miss making it waterproof.

I will be getting a cap (Leer 100XR) installed next week. Before then, I'd like to do my best to waterproof the top of the bed/railcaps before the cap is installed.

For those with caps/experience, is there an understood "best way" to achieve waterproofing that I may have missed?

Thanks.

 

Having issues with my 100XR as well and would like to know the same thing. Mine seems to be leaking up front and at the rear. It seems like it wicks from the rear glass forward with the lower part of the headliner. I trimmed the carpet some since it was sticking out but still seems to leaks. I'm hesitant to bring it back to have them fix it since I'm sure they will just throw a shit load of caulking at it and would rather fix it correctly.

 

100XR? Been there, done that. May god have mercy on your soul.

0. Use a butyl-based sealant, such as asphalt or roof sealant. Available at Home Depot and very cheap.
1. Take off the front header rail. Pop out the rubber caps on both ends, seal them, then run bead of sealant UNDER the rail, then mount the rail back into original position.
2. Fill the gaps on both ends of the rail as much as you can. In fact, overfill them to the sealant is a bit higher than the adjacent rail.
3. If your cap will have a front removable window, it'll leak around the perimeter of the window.
3.1. If the front window also has a slider, it'll leak in the slider.
4. If your cap has windoors, they will leak around the perimeter.
4.1. If your windoors are sliding variety, they will leak at the slider.
4.2. Can you guess what the locks on your windoors will do? If you guessed "leak," you're a winner!
5. Before installing the Leer canopy, take off your bedside caps (plastic ones along the top of the bed sides) and apply sealant underneath them. Also consider adding some thin (1/8") weatherproofing to act as padding between the cap and the bed, otherwise the cap will scratch the paint underneath it once the canopy is on.

Fuckin' enjoy.

 

Somebody mentioned this stuff and I'm about to order some:

$27 Great Stuff 283064 12OZ GS Pond&Stone Foam Sealant, Each, Black

https://www.amazon.com/gp/product/B001AQ0FVC/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

Just had the 100xr installed 3 weeks ago. Its actually fairly water tight. The only spot I get leaks is at the corners at the front of the bed. I can see a small gap so I'm hoping this'll seal it right up. It'll probably be a mess if I ever remove the topper but not sure I will. Just gonna buy a piece o shit trailer to haul mulch, etc.

Anyway, I also notice some larger gaps where the topper back window meets the tailgate. Amazingly these don't seem to leak so I'll probably just leave it. Weve had a couple heavy rainstorms so I'm hoping these won't leak much in the future.

 

When I had my ARE V series installed, a part called a "Tacoma bed gasket" was used and I have no leaks. I have no carpet so I don't have to worry about wicking, but it seems there is a part missing on some cap installs.

 

$30 3M 5200 (06504) Permanent Bonding and Sealing for Boats and RVs Above and Below the Waterline Waterproof Repair, Black, 10 fl oz Cartridge

3M 5200 Marine Sealant/adhesive?

 

Great product to use

 

I got an ARE cx installed and they did a great job on sealing around the rails. I was having leaks come in from the front corners, right under the rails. I just put some black caulking in the corners and spread it with a putty knife. Haven't found any other leaks yet, good luck.

 

LOL someone will glue their canopy on permanently with that stuff hahah

 

Yeah that 5200 marine sealant is no joke

 

$16 ESI Front Rail Seal 6ft EPDM Rubber

https://www.amazon.com/Front-Rail-S...=1494279486&sr=8-3&keywords=truck+topper+seal

If it's the same as second gens, I've used this on the front rails with good success. It's much taller, which helps because the front rail sits lower.

 

Well shit, got to test 'er out pretty good today. Not quite as watertight as I thought:

 

These plugs are helpful, 99.9% dry with my Leer 100XQ

https://www.tacomaworld.com/threads/rubber-plugs-for-gaps-in-bed-rail-available-now.420884/

 

I used that product after it was recommended here and I wouldn't do it again. VERY difficult to cleanly remove. And when it dries, it's a very hard, plastic-like substance. It's better to use something that'll still be flexible and somewhat soft.

 

Mine doesn't leak in any of those places. Otherwise there is some good advise in that post.

My installer used what I think is referred to as dum dum. It's a non hardening sealer kind of like black putty. They didn't seal under the side rails and I have some leakage there. I had some drips at the front corners and I was able to squish the sealer in there better. So far so good.

 

This is "dum dum" or "elepahnt snot" as we called it before in the car audio industry and dealerships. Made by 3M. Works well for all sorts of stuff, but a pain to clean up. Is this the stuff @0210 was referring to also?

$31 3M Strip Calk, 08578, Black Color, Soft Butyl Rubber, Paintable Immediately, 1 ft Strips, 60/Carton

https://www.amazon.com/3M-08578-Black-Strip-Calk/dp/B000PEZ1L4

 

Hell yeah! That looks perfect for the few spots I need to plug. I'll probably snag some of this..

 

Thanks everyone for your input into this thread.
I'll post what I end up doing for leak prevention and how it worked (if at all)

 

Hey guys, I am in the market for a bed cap, I own a 2018 double cab 5 ft bed. My top priority is having a waterproof bed for storage as I only have the back seat at the moment. Is there a brand that tends to have less leaking? I have heard snugtop is better than most, it is also more expensive than other brands. It seems that the leaking is hit or miss and the design of the bed itself and the quality of the installation are also major factors for leaking. I dont mind spending the money for a top quality bed cap but if it leaks I might as well just keep using my tonneau cover. Any advice would be appreciated!