Leaking 100R Leer Topper on '19 TRD Sport

First post here, need some tips/strategies for my leaky Leer topper.

Brand new Leer 100R topper installed on my '19 TRD Sport just weeks ago -- I've taken it back to the installers after a huge rain revealed some wetness/soaked underside of the carpeted shelf (where the bed sides meet the topper), mostly near the hatch. They (apparently) took it off to check the seals and tighten the clamps. I'm not sure if they use the best sealing material, however.

Then, on a long road trip, I was smacked with LOTS of rain on the interstate. After the trip, it appeared the leak was not fixed. I need to note I built a box of carpeted bed drawers with removable lids on either side of the drawer box (pics included). They were soaked on the undersides.

Some others that have looked at it think maybe the carpet of the topper is wicking water from the small corner gaps in the tailgate, where the hatch meets the tailgate. Simply due to the amount of water, I wonder if the leak came in from the undersides of the topper shell. Has anyone experienced this? If so, what'd you do?

 

Probably not the cap but the bed. Was bed front rail sealed? Bed side plastic rail covers will also leak. Pull em all seal beneath, fill gaps at each end of bed frt rail. Rubber seal the tail gate areas. Very common. Surprised bed installer didn't know problem areas.

 

I believe the front rail was sealed, yes. And I haven't noticed any moisture near the front rail. I suspect the sides/rear. I also think the clamps are attached via the bed-side rails.

 

That plastic bed rail top is junk and wish I had removed mine before building my cap. I'd remove it and find whatever blub seal you like to stop the leak.
McMaster Carr has what you need.
bulb seals | McMaster-Carr

 

My old cap used to leak from the windows. It would soak the carpet in the corners and then drip down into the bed. It wan't till I was sleeping in the back of the truck on a rainy night that
I figured it out.

 

Ya it's unlikely the cap (canopy) or its seals to the top of the bed rails. The Tacoma's box lets in water badly IMO; the front of the box (at the cab) seems to act as a rain gutter and water runs down the front corners--those holes in the bottom of the box aren't there for nothing. I've watch YouTube tutorials on how to fix this and they're doable if you're so inclined; but what a pain in the ass. Bed rail caps are a similar story. Also, even with a tailgate gasket the tailgate doesn't seal well. And while I'm bitching haha I'll add that the storage cubbies also get full of salt and crud because the tabs fit into holes that are open to the underside of the truck.
I camp in the box and am intimate with this issue--I've considered switching back to a Frontier as it was never a problem with that truck.

good luck to you