Composite Bed Rail Leak

Bed leaks have been covered in many threads before, but none that I have found covers what I believe I have found on my truck.

Water is coming up through the rear wheel well and going between the composite bed lip and the metal fender rail. I would have thought Toyota would have put something there to seal things up a bit, perhaps not. This is not a simple leak only involving water as grit from the road is entering as well. This tells me the gap is large.

Before I put on a shell this made no difference as the bed was open to the elements, but now with the shell on, the dirt the tire throws up from the road is finding its way into the bed in copious amounts.

I had read about:
the front bed corners leaks, I used windshield urethane to seal
the front rail leaks, I used Butyl tape to seal
the leaks between the plastic bed rail covers and the metal fender they attach to, again I used Butyl tape on the interior edge.
BUT nothing about any sealant problems between the actual composite bed and the fender.

Has this been covered and hopefully solved? Or is it a new revelation for this forum?

Edit: Clarification of what I have done to seal things up.

 

I believe I know what you’re talking about and had the same issue after thinking I fully sealed the bed when installing my Leer topper. The leaks I still had were what you described on the driver side near the back of the bed rail and the storage cubby. I ended up fixing it by getting under the truck at night with the bed lights on and using gorilla weather proof tape over the inner seams up under the fender. Then I got in the bed and cut little pieces of butyl tape and jammed them up under the lip between the metal edge and composite bed and pushed them up with a plastic scraper and put more till it seemed full. Hope that helps.

Also it will only leak from this location after driving in the rain with the tires kicking up water and debris, so you’ll have to go for a drive in the rain after to tell if it really fixed the issue.

 

Yup, that is it, thanks for the confirmation. I'll wait for some more responses.

 

I’ve also seen other people have bought full aftermarket plastic wheel well liners for the front and rear that would eliminate most water splashing up from the tires also. Have not seen them in person so idk but have seen links to them on this forum before.

 

I will have to seal this at the bed as I will be cutting the rear fenders up later on for a full high clearance bumper. Thinking of using the urethane again, it seems to have adhered well and has some flex.

 

I get some water/road salt dripping down from where the topper shop bent the metal fender out to run the wire down there. I also get some water and dust from where the bolts hold the tracks onto the bed sides. I did all the other sealing you mentioned.

 

Interesting never thought about running the wires there, kind of regret drilling into the side of my bed now. My leak is from the exact same location and fixed it by doing the above.

 

When you pull those plastic bed rail caps, You will know why there is a leak.

The entire top horizontal portion of the metal fender is nothing but a string of holes. And those holes look Right at the tires!

Solution?

Pull those caps and run a bead of cheap* calking down both edges of the perforations. *(you might want to take it off some day). Then reinstall the cap.

The plastic cap has some depth to it, so a simple film or tape won't seal things up. Though I have seen, on these very TW forums ..somewhere..., of just running a strip of packing tape over the entire area, then adding calk ..to aid clean up. The cap would then punch trough the tape on re-installation.

 

If I am correct he’s talking about a leak between the metal lip and the actual composite bed. I pulled my caps and taped and used silicone caulk like crazy and know it is not from under the bed caps. When driving the tires would kick up water that would leak like in the pictures from under the metal lip and composite bed itself. Not from under the caps, I triple checked on mine and was not from under the caps, slightly below it.

 

I guess I haven't looked to that area. My bed leaks, It's a truck..... ;-) Softtoppers and bed mats RULE! ;-))

 

I can see that happening. The better way is to drill a hole (and add a grommet) to run the topper wiring:

 

TacoWorldDan has it right, my problem is between the composite bed lip and the underside of the metal fender lip. I'll probably be stopping by a dealership to see what the parts department illustrations say Toyota puts there to seal things up, or not.

 

Looking at this image, from when I installed "proper bed rails". I don't believe there is any sealing element. Overlap only.