I recently got a 2010 supercrew and am going to be putting a rubber mat and a extang trifecta, with a free tailgate seal on it. I am surprised by the size of the gaps on the bed.

I drive on a lot of dusty gravel roads, in the past I just rolled the tonneau to let the dust blow off. If I didn't everything was covered bad with dust and there are quite a few gaps on the supercrew's box.

It looks like to do a good job every seam should be caulked, not just on the front of the box. Has anyone ever done this and what caulk did you use?

I know it won't make it dust proof but if it isn't done it looks like it will be real dusty under the tonneau. I may even leave a few small gaps in the corners for drains.

 

Clear silicone caulk works well, and you don't really notice it once it cures.

I put a high wattage light at various points on the outside and underneath, after I got the cover on.

Climb into the bed, and caulk where you see light coming thru. I sealed everything, figuring if water can drain out, it can also come in.

 

Thanks for the reply, I did all the cracks with silicone, I don't know why there are such gaping cracks in the box, when a few drain holes would seem to be enough.

Did you do anything with the plastic bed rails? I know dust collects under them so I assume it would come in underneath them also. I'm more worried about dust than water. I thought about caulking along the inside, or just putting some tape on the seam on the inside.

 

If you have a black box, use black silicon.

 

Sorry, can't offer advice on the bed rails. I have an aluminum Diamondback cover, and when it is closed the gasket on the cover compresses and pushes down on the bedrail, tightly, so I don't get dust coming thru under the rail.

I went atv'ing last month, down a 19 mile gravel road to the staging area. Had to wash the truck, didn't need to touch the bed except around the tailgate seal.

I could not find Red Candy Metallic caulk at Home Depot. They were out of stock.