Dust seal for underside of bed rail caps
 

This is for guys who travel dirt roads and discover dust gets inside their camper shells or tonneau covers by migrating underneath plastic bed rail caps.

I decided to try foam weather seal to stop dust migration underneath bed rail caps and cut down on dust getting under a tonneau cover. I also included a tailgate seal and added weather seal on top of the front rail. Weather seal on the front rail makes up for a height mismatch with plastic side rail caps to aid tonneau cover front seal fit.

Decided to try weather seal instead of silicone caulk for two reasons. There are 1/4" stand-offs on the underside of bed rail caps requiring a bead greater than 1/4" high to seal. And if there is ever a future need to remove the caps it will be easier. It appears silicone caulk or another filler could be effective too.

For those without a bed liner, (like me), holes and seams associated with stake pockets will admit dust and need to be covered as well.

Weather seal was purchased from local True Value hardware store, bulb style tailgate seal obtained via extangfactoryoutlet.

Annotated pictures are of a 2011 SC

Interesting post. I have a hard enough time sealing the bed elseware. I bought a tailgate seal and have a bed rug. I am considering using silicone sealant for the slots in the bed floor that are openly exposed. I want a perfectly sealed bed. Trouble is i cant be sure where all the dust comes from. Any ideas.? I have a tonneau cover that is sealed all the way around currently.

Camper dust experience
 

The tailgate seal hadn't arrived in time for the truck pictured above to go on a camp trip over quite a few miles of dusty road. Instead several of us took another Ford with a newly installed camper shell plus a bed liner, (tailgate seal too).

The tailgate seal and camper seals worked just fine. We were really surprised at the quantity of dust that got to our gear migrating under the bed rail cap. Good thing the bed liner was in or think the gear would have been much worse off. Looked behind the back end of his bed liner this morning, it's full of dust there from the rear stake pocket holes.

I figure my truck would have the same problem. The tailgate seal arrived yesterday so pulled off the tonneau cover and dealt with most of what I know needs to be sealed, haven't done anything yet for the stake pockets. Stall mat covers the bed bottom and think it will keep most dust intruding from the floor out of things, we'll see.

Word of caution, when pulling the caps be careful. There are a lot of fasteners to loosen. The tool I used to unfasten them was a long screwdriver pressed against each side. It slipped and one of mine is now missing. The portion of the job to remove, seal, & replace the caps should be easy for guys who do use tools, should take about an hour plus the trip for materials.

Stake Pocket Seal Link
 

This is the title of my later post to this forum for what I did to seal the rear stake pockets Dust sealing rear stake pockets 2011 SC

So the WeatherSeal you used under the bed rail cap was 3/8" thick? And it would be a little thicker on the front bed rail: 1/2" Thick?

Thanx for all this info. I'm getting a Leer cap for mine and want to get this sorted out before it goes on.

Weather seal size used
 

WeatherSeal used on mine came packaged in 10' rolls. One roll 7/16" thick x 3/4" wide, the other 7/16" x 1 1/4" wide.

7/16" worked well along the front rail to augment Estang's seal. And while the bed rail caps went back on easily, compression was more than necessary.

Choices on the shelf for me were limited and 7/16" worked out OK. But I think you are correct and 3/8" WeatherSeal would be a better fit choice under the caps.

My buddy's truck with a new Snugtop installed was on the trip we identified bed rail caps leak dust from underneath. His shell has the typical wide oval cross section seal. That seal did not leak at all including along the front bed rail. We'll seal under his bed rail caps but do nothing along front bed rail. I added to the front rail of mine because Estang's tonneau seal isn't as robust, barely making contact across the front due to the mis-match in height with Ford's plastic bed rail caps. And doesn't fill in the transition from the side rail caps. On trucks with-out the mismatch Estang's seal should be fine.

OK, I'll check with the Leer guy about what they do with the front rail seal.
They may have it covered. Thanks again.

useful info
 

This is good stuff. Thanks for posting the link to this on your other thread.
It does seem like a design oversight on the manufacturer's part to not seal between the rail caps and the bed. Now, between the truck and cap[topper]/tonneau you have two seals instead of one.
Further, this might, in part, explain the difficulty in making my cap water tight. Here, we get LOTS of fine, misty rain and it tends to draw into gaps the same as dust. Extra clamps on the rails and silicone sealer seems to have done it but I like the idea of sealing between the bed-rail caps and the bed. I didn't realise they were so easy to come off.

OK, got something called "Tago Stopdrafts" at the Canadian Home Depot, "Closed cell sponge rubber tape", 3/8" thick and 3/4" wide.

They also market a wider version for sealing the bottom of truck caps, so it should be good for under the plastic side rails.

I was told that the Leer Cap will be installed on top of the plastic rail caps, They will fill the gap on the front rail without the plastic cap, and I got them to put on a tailgate seal as well. But I will put this Tago stuff under the plastic side rails myself.

Question: has anybody tried to put this stuff under the *tailgate* plastic cap? Is it even necessary there? How easy is it to get the tailgate's plastic cap off? (Too rainy for me to go outside and look myself right now ...)

Should not be needed under the tailgate trim.