Bed Rail Caps, 3rd Gen., Tonneau Prep

I couldn't find a good selection of pics for this topic, so I thought I would contribute some.

In preparation for installing a DiamondBack HD, I wanted to seal along the outside edge of the plastic rail caps to prevent leaks. With a little black silicone (GE stuff at Home Depot), that was easy enough.

What I missed in the process was that DiamondBack also sold shims that fit under the caps to fill in the gaps left by the small ridges that provide some buffer space under the caps.

Below you'll see the tabs that hold it down. It wasn't difficult to remove them by hand, but popping them by sliding a panel removal tool in and pressing against the tab certainly made it easier. I broke no tabs during the process.


A little too much silicone. Just wiped it up and slightly back under for a clean look. No more slight sliding of the rails rubbing off the paint.

-WV

 

Can anyone elaborate on the shims the OP is referring too? I get leaks where the center section clams down because the rail collapses just enough to let water in...…………..

 

They don't make it easy to find:
https://diamondbackcovers.com/pages/installation-guides
lower right under other components.

https://cdn.shopify.com/s/files/1/1...-cap-shims-tundra-installation-guide.pdf?2489

Quick search engine tip: Limit the scope of your search to a particular site. In this case I used (at Google):
site:diamondbackcovers.com shims

-WV

 

thanks whiskey...…….I just emailed Diamondback. Hoping they will send me a freebie...…………...

 

I'll put this in a separate post, but there's another shim that really helped me.

I needed to fill that gap along the front rail as my bedliner covered rail sits about 1/8" below the plastic caps. Some people said the gasket filled it in nicely, but I didn't want to risk it, so I improvised a filler shim from a garage door sweep strip I purchased at Ace Hardware. The DB HD comes with a stick on gasket, but I didn't trust it to stick and work well on top of that grainy bedliner.

Looks like this:


Once again, a couple lines of black silicone and it looks like it was meant to be there. The sweep is something like 15' long for about $15. If you screw it up or want to contour cut the ends, you'll get a second chance.

-WV

 

Talk about good customer service...I received an email back within minutes. Diamondback is sending me the shim kit. Diamondback is awesome to deal with...………...

 

Thanks for posting this I'll do this when I get one.

 

I need replacement bed rail caps where can I get them? Other than the Toyota dealer

 

I just got a set on eBay for $65 shipped

 

Sweet just found em Thanks

 

Any one try these I'm looking to.
https://www.ronusa.com/bed_rail_caps.shtm

 

Hard to beat Diamondback!

 

I have leaking in my bed with my Diamondback. The water seems to be closer to the tailgate, not the rear window. Diamondback sent me the shims, but I haven’t installed them yet. They seem to imply that the water comes in because the bed rail cap is too thin and bends once the Diamondback is installed.

My question is, do the shims really stop the leaking, or do I also need to apply silicone? I guess I assumed that the water was coming in between the seal of the Diamondback and the surface of the rail cap, or possibly through the gap at the ends of the tailgate.

 

I removed my Diamondback today and installed the shims that DB sent me to hopefully eliminate the leaking. I was amazed how distorted the bed rail caps were at the center section of the DB.

 

Here are photos of the bottom side of one of the plastic caps with shims installed and the (sloppy) bead of silicone that I ran to try to ensure no water intrusion...

 

And here's everything reinstalled. I'm a bit concerned with the large gaps between the bed rail cap and the bed at the center section. I think this is a combination of the shims and the previous distortion from the overtightening of the Diamondback by the installer. I sent the photos to DB...hoping that the leak issues are solved and that the gaps between the plastic and painted metal aren't going to present new issues.

 

Great write up. I'm looking for a cover for my Tundra and Diamondback is at the top of the list. All together how are you liking it so far? I'd be installing it myself and would get the SE since i have no need to put more than 400 lbs on top of it.

 

I love it so far. Not only for the way it looks, but for the security it provides for the bed. I also opted for the SE, and had it installed by the Diamondback dealer. But after having to remove and reinstall to reinforce the bed caps, it wouldn't have been difficult to install myself. I'd make sure to request the shim kit from Diamondback and install those before you put the cover on.

 

I just installed my DB SE yesterday. They now include the shims when you order for a Tundra!

The shims are a dense rubber (or possibly urethane) and are positioned as pictured:

Here the adhesive sides are up while I positioned them.

I found the most difficult part of removing the cap to be the rearmost clip. I had success working a plastic tool around the perimeter of that last clip several times as I gently pulled.

Using the shims does seem to prevent the cap from being distorted, but the cover has only been on a day. I’ll come back and update if I do see that the cap is being compressed/deformed.

I am extremely pleased with my new DB cover. The quality is the highest, the kit and instructions were very precise, and it looks and functions as good or better than I dreamt it would.

 

My DB cover gets to me on Tuesday, should be interesting receiving the 250# pallet at the bottom of my uphill driveway. It's not bad but maybe my wife signing for it while I'm at work. I got the HD mostly because...well I weigh 185 pounds and figures maybe I'd want to stand on top with more than just one of my friends. Hope I can get it installed in 5 days before I go out of town for 3 weeks! We'll see.

 

How are the shims working, I have an HD on the way and don’t want leaking.

 

So far so good. We have had steady rain and some snow that accumulated and melted on the DB cover. Have seen no water intrusion, and I can’t install the bulkhead weatherstrip until I see temps over 50 for 24 hours.

One thing I did notice is that when it gets freezing, you can get frozen condensation on the underside of the cover. When it melts, it will drip. That’s all though.

 

Bonus points for the security. I’ve had multiple bums and panhandlers fishing in my bed at freeway off ramps. Sucks right after a Costco run. With the DB and a big can of pepper spray, I believe the tables have turned.

 

without the shims or weather stripping on my diamondback hd, the only time it leaks is the high-pressure touchless wash and power sprayers. Other than that it's been solid. I'm still putting the shims and weather strips on, but I have to wait till spring when it warms up.

 

I'm still getting some leaking, in the same place (driver's side, middle of bed and back towards tail gate). Diamondback is sending me some weather stripping to add. I'm not sure if it's because my bed rail caps are still warped or not. And I'm assuming that the water is coming in on top of the bed rail cap, and not underneath, but I'm not sure. Hopefully when the weather warms up and hopefully heats the warps out of the plastic.

 

We've had a little precipitation in the last couple days and mine's appeared to be watertight, I love it so far. Threw my snowboard gear in today and was glad to not have to worry about the stuff I left in there walking off while I was on the mountain. These things are SOLID, I'm loving it!

Feel free to use my link for purchase and a kickback for me. Then you can get a link and get a kickback from your friends' purchases: Diamond Back Covers

 

I just got my cover in and broke a tab trying get the bed rail caps off. Should I replace it with an oem cap or will aftermarket work just as well. I got quoted $204 per side from my local dealer

 

My only experience is with an OEM cap that was installed by a body shop after they broke a tab when they had to repair my driver bed side. They were picky about getting OEM, and it is a perfect match. I can’t speak to aftermarket.

 

I broke a tab or two and it installed back on pretty secure with no movement.

 

Yeah, I'd probably just try it as is and think about replacing it if the fit isn't up to par.