Not a rail cap... so what is the part?

The piece that runs left to right along the cab window is missing on my 2015 bed just above the rail system. With the rail covers on either side, I can't add a topper to the bed without a serious gap where water will come through. Can't find a part number anywhere and technically don't even know what the part is to describe it to the dealership. Assuming it's a plastic piece the same as those on either side. Any insight?

 

I don’t think they come with a cap right there, but I could be mistaken. I do know that I’ve always had to double up my canopy seal tape in that specific spot.

 

When i put my cap on I ran a thick layer of solid weather seal from Amazon. If it’s not thick enough then I would start looking for parts / making something from plastic or metal.

 

You aren't missing anything there, I have a 2010 I bought almost new and it's the exact same.

I'm not sure about how toppers install though, perhaps they have something to take up the space?

 

Maybe I'm missing something here, (wouldn't be the first time/unlikely to be the last) but on my 2014, the plastic "piece" running across and directly behind/adjacent to the rail (and level with it and touching it) is actually the front/top of the bed. (The edge of it is about 1.5" from the cab.)

FWIW, When I got the truck, it had remnants of adhesive and black foam on it which I assumed was from a weather strip for atonneau cover or topper.

 

Here’s what my 2008 access cab looks like…







pretty sure this is literally how they come from the factory. If you wanted something to make it level with the side caps, you’d probably have to fashion it yourself.

 

Your truck is factory as far as that area is concerned. When you put on your camper too, lay down a couple extra layers of the foam weather strips. It will seal up just fine. I know it sounds strange but mine has always been pretty water tight.