Has anyone sealed the box sides to the floor on their box with the factory applied liner? The liner appears to have been applied before the box was assembled.
I installed a cover last week and noticed day light where the box sides meet the floor.
Anyone used an RV lap sealant in black to seal it up.

 

My ford liner was sprayed after I purchased the truck. I have the same as you, with daylight between the sides and bed floor. I have not sealed it up yet. But I have not sealed it yet. I havent noticed any water coming up through. Not sure if I will seal it yet.

 

I am not so much concerned with water as much as I am with dust.

 

Those gaps are there for drainage, they say. I have the dropin Ford liner, so I can't tell if there's any in the front of the bed like used to be.
If any are going to caulk those "drains" with silicone, be sure to get a type that is compatible with aluminum.

 

Ok. I would not use silicone. I would use a elastic polymer like Proflex or something similar. Silicone wont last very long, and nothing sticks to silicone when you have to patch it. Not even more silicone.

BTW, I drove on quite a few dusty gravel roads this week, and didnt get much dust in the box. I have a Bak Revolver bed cover.

 

 

When I bought my new truck, I noticed how much of a gap there was in my '18 6.5 bed vs the old '09 6.5 bed. I don't really think the floor-to-sidewall gaps are for drainage--that's the seam at the very front of the bed. Not sure if it's related to the new aluminum bed construction or simply a QC problem. When I had the Line-X sprayed in, I asked if they could try to seal the side seams and they said prolly not due to the width of the gaps. For those who mention wanting to minimize dust intrusion into the bed, I wonder if sealing the underside of the seams with the silver aluminum duct tape--same stuff HVAC contractors use to seal air ducts--would be a semi-permanent solution. That stuff sticks better than anything I've tried...or maybe the Gorilla tape?

 

Look into DIcor lap sealant(non self leveling). I use it on my campers and it is the best stuff out there. Not sure if they make it in black though.

 

I wouldn't bother if I were you. Driving in mud, dirt roads, wet roads etc always leaves the inside of the box clean. Most of the time the box is the cleanest part of my truck, and I don't have a tonneau or anything. Nothing ever comes up through the cracks, and the aerodynamics keeps anything from getting in there when I'm moving.

 

I sealed my 2015 bed seams with a urethane product. When used with my BakFlip cover and tailgate seal, it kept out most of the rain and dust. I have not done it to my 2018 yet.