2020 SCrew, 5.5' bed. I've had this truck for a few months now and I've noticed small gaps between the bed floor and the sides. I can see light thru 1mm gaps in places. I didn't think it was that big a deal but after driving lots of dusty dirt roads last week I notice plenty of dust in the back, mostly around the gaps. (I have a cap on the bed).No windows open in the cap.
I suppose I could run a bead of silicone around. I don't want a bed liner. What have you used to seal up those gaps? On the inside of the bed or from the outside?
TIA

 

Those gaps are common, as far as I can tell... I have a factory liner and they are present. I suppose some silicone wouldn't hurt, but I'd stay away from anything that would prevent movement; the bed may need to shift when the suspension is stressed.

 

Those gaps are there to provide drainage. Most people don't run caps/covers and those gaps let the rainwater drain out of the bed. I would be wary of what I used to seal the gaps - I've read that unless you use something designed for an aluminum bed the sealant can cause corrosion. There are sealants specifically designed for aluminum but I don't know what they are...you'll have to do your own research.

 

Same, factory spray liner here and have those gaps in the bed.

 

I had my bed Line-X'ed and they purposely left those gaps, albeit smaller now, but the point is they made it a point to not block them, completely. If I look at the correct angle, I can still see some light through there. They're for drainage.

 

Same on my last F150 with the Line-X bed. Even under the tailgate, the shop taped off so that liner wouldn't close the gap.

There are other threads in this forum in which members with bed caps describe what they've done to close the gaps and minimize dust intrusion.

 

I siliconed my gaps prior to putting a bedrug in. No leaks. After this, I learned silicone was a VERY bad choice for aluminum. Maybe the paint is a good barrier, but 4 years later, not any issues. I'd use something els if I was to do it again, but the cracks are normal for drainage.