Bed Lets Water In Through Front Seams ... How Can I Stop It?

Bishop · August 25, 2011

Odd question/topic so will try and post it haere as well.

Calling GMC got me nowhere

Hello all,

Have a 2009 GMC Sierra 1500 Extended cab with 8' Bed.

I keep tools in it and the bed is capped, but with driving through rain, am getting a lot of water in the bed ... not so good for the tools.

Cap does not leak, bed has a liner.

But ... I can see 2 opening in the top front corners of the bed, almost like weep holes but in the top corners. I can see them and insert a finger to the outside where the liner does not go all the way up too. Seem to be in a v shape in the seam maybe 3" long, a sliver at the bottom, 1/2" at the top.

Seems when driving through the rain, the air flow between the bad/cap and the cab just forces water into these 2 openings, and when its raining hard, really dumps some water in. It not only can allow several gallons under the liner and inside, but get in with enough force that it can spray the bed all the way back to the rear wheel wells.

Is this common?

The one thought I had was to try and make the whole bed waterproof and sealed by going with a Rhino liner. I would imagine the opening would need to be sealed somehow first than sprayed. Trying to figure out if the holes have a function, maybe flex for the bed or something similar. Worried that if I seal the corner, maybe with a weld in the corner using a v-plate of SS. then have them spray coat the Rhino Liner, would it effect the bed negatively or eventually crack?

If anyone has any insight, it would be much appreciated.

Also is an issue as I hope to use the truck for camping in the future and sleep in the bed, so watertight would be a nice thing

Any thoughts appreciated

sic lsx · August 25, 2011

When I workat at a truck accessories shop. We always used foam tape around bed before installing them. Two layers across back by rear glass and one going down sides. Never had anyone come back.

Bishop · August 25, 2011

When I workat at a truck accessories shop. We always used foam tape around bed before installing them. Two layers across back by rear glass and one going down sides. Never had anyone come back.

Sic, you mean before you sprayed them with a liner like Rhino?

So I'm gathering the holes are meant to be there?

Dealer has no clue and GMC doesn't know what I'm talking about

I'm guessing you are taping the inside corners and there may also be holes under the rail?

Sorry if I sound confused, plastic liner was put in at GMC, so can only see a bit.

Can't really tell what's there without removing the line .. and I definitely can't get my hand in form the outside to apply anything, not enough room between the cab and bad to do that.