Another diamondback question

Hi all!

I recently installed a Diamondback HD on my 2021 Platinum. I noticed a couple of small leaks and wanted to verify some install steps.

1. I am noticing a small leak on the drivers side/cab end. I saw there was a part about adding silicon in and wanted to verify where it went. I added some in that crack between the bed liner and the rail (Red). I noticed water was creeping in under the bed rail so i put some there too. )(Yellow)



2. Does this alignment between the bulkhead and cover look right? the cover is lined up with the outer edge of the bulkhead.

3. I noticed the gaskets in the center panel were already flat prior to tightening. A small amount of water is coming in...should i replace the gasket? The center part isnt tightened very much...just enough.


Thank you!
Matt

 

Hey Matt,

When I installed my DiamondBack by myself I had minor water issues because I didn't adjust the guide brackets for the locking rods tight enough to compress the watertight gasket. Looking at the pictures above I would say that the front and back portions of the cover need to be tighter to compress the gasket and provide a better waterproof seal. When I installed my cover I had to stand on the cover to lock it that is how much adjusted the locking rod guides to provide a good tight waterproof seal. Overtime this has loosened up so I do not need to stand on the cover anymore to lock it and I still have a tight waterproof seal.

The other good idea is the light test- On a bright a sunny day open your tailgate and you shouldn't see any sunlight. If you do then that is a point of water entry as well.

I would start with these steps and go from there. Also, make sure your center panel clamps are tight as they will loosen up slightly during the first few miles.

 

I had to run a bead of silicone in the gap between the rails and bulkhead, including down slightly into the bed. Use a flashlight illuminating the area between the cab and bed and look from the rear to see how far you need to go.

You’ll also need to run a bead under the bed rail caps across the full width on the cab side to stop leaks in that area. When the cover compresses the caps they tend to bow upwards on the outside edge a little.

At the center support you definitely don’t want to overtighten it. You have the included spacers under the bed rail caps, right?

I have found that parking on an incline causes water to pool in certain areas around the center support, and then when I drive around it can snake it’s way into the bed. The tundra bed rail caps are the culprit, as they flex, warp, and allow water underneath.

 

Man I wish I could help you, but it is hard without actually being there and looking at it. All I can say is mine has never had that problem. I installed it myself almost a year ago I think and I also have the large tool box that sits across the bed that is putting extra pressure on the bed rail caps. I have it loaded down with tools, rope and chain too, so I know there is some weight there putting pressure on the caps in that area for sure from the lips of where the toolbox hangs. In the last week of May I took a trip to Louisiana. We got caught in one heck of a rain storm one evening that lasted at least 2 hours as we drove. Very hard driving rain and had to reduce speeds to around 30-40 a good deal of the time. Even in that I had no leakage.

I think what Dan is saying is solid advice. Make sure everything is tightened down well enough that the seals can compress and do their job, close yourself up in it and look for light. Maybe even have someone run a hose with some pressure over the outside while you're in there. If none of that helps, call DB. They were real responsive to me when I was purchasing; but I've never had to call them again since I've had no issues.

 

I had a friend stand on each corner of my DB as I was in the bed tightening the locking rod guide brackets to try and get some compression on the gaskets. I didn't use the additional bulkhead gasket that they provided, but had it around just in case. I tried using a 50 lb bag of concrete and still had water intrusion issues. Once I had a friend help me...I've had no water issues.

My DB has been through (2) named hurricanes on the NC coast with bone dry gear after each storm.

 

Yep. I used two 100lb dumbbells for weight as I tightened.

 

I did similarly (used weight to hold the cover down and compress the seal) when I adjusted my brackets. I’m in Oregon where we get a ridiculous amount of rain, and I’ve never had a leak. I also never use the front bed seal, nor any silicone, as I just never had to.

Since we are talking about DBs…

I recently crawled into my bed with the DB closed up to clean some stuff out of the front corner. It occurred to me while I was in there that if the tailgate got shut, I’d be stuck in there with no way out.

If one of my kids shut the tailgate with me in there as a joke, I would be helpless!

Had anyone thought of this? It occurred to me during a really hot day a week ago or so.

Creeped me out enough that I’m going to throw a tool back there to loosen the locking mechanism.

 

I don’t think my kids would do this BTW… they're not that psychotic….

 

This is how I have my front cap.

 

Leave an Allen wrench in the bed so you can undo the locking rod set screws.

DB replaced my whole cover because the first one leaked like crazy. My second one is better but until I did the silicone at the front corners it also leaked. I suspect it’s because I park on an incline, so the water would run right under the rail caps and into the bed.

 

One step ahead, and done!

 

Here is how mine is fitted: