Originally Posted by shiftz33
December 05 in Northern CA was a wet one. My 05 SSR experienced a lot of water leakage in the covered truck bed area. After I picked up my 05 SSR from the service department (for other repairs), I decided to try and find the leak(s). I was told the sales manager at this Chevy dealership also had truck bed leaks and that GM ended up using silicone sealant to resolve his issue. It ends up that's how I resolved my leaks as well.
1) Vertical rubber seal on side of tail gate (top end)
2) Vertical rubber seal on side of tail gate (bottom end)
3) Smaller rubber seals on each end of the top side of the tail gate
4) Tail gate sill plate (plastic) weather stripping (what a joke)
5) Small gap between sill plate and the round rubber seals
6) And the big leaker was the seam between the rear bumper cover and the truck bed.
1) There is a hole left unsealed when lid cover and tail gate are closed at the top end of the rubber seal on the side of the tail gate. This rubber seal has an internal drain chamber that collects water via a small lip that at the top of the seal. That small lip does NOT go up enough nor high enough (on the front side of it) to seal off the gap that exists between all of these parts when everything is closed. You'll see in the attached photos how I used silicone sealant to "extend" this lip/cup area to close off this opening. This helps to prevent directional water leaks.
2) Any water collected by this seal on the top end drains down the internal chamber to exit at this end of the seal. The big problem being that this rubber seal is not in full contact with the bumper cover nor the truck bed so any water that finds its way here, will have full access to the truck bed (under the carpeting). I used silicone sealant to seal off this with a line of silicone running to the edge of the bumper cover. Thanks to a tip found on this site.
3) The tail gate has two tiny rubber seals that are to direct any water that gets past the seal on the bed cover to the sides and into the drain channel identified in #1. The only problem being that the these tiny rubber seals only have double sided tape on their bottom half. This leaves the top part unattached and any water that is present there will drain down into the truck bed instead of being directed to the drain channel (in #1). I used clear silicone sealant to fully attached these two little buggers to the tail gate.
4 & 5) The plastic sill plate that sits under the tail gate when closed was another source for water. I placed a small amount of silicone sealant at each end of the sill plate cover, but that needed to be removed and replaced to fix #6. What I found when I removed the sill plate to fix #6 was that sill plate seal was a poor excuse for a piece of weather stripping. I ended up pulling off the weather stripping and using a generous portion of silicone sealant to establish a water tight barrier when I reinstalled the sill plate.
6) The biggest water leak of all.
The rear bumper cover appears to be a good tool for directing water up to the truck bed while driving down the road. With everything else sealed as I've mentioned, I was still get large amounts of water under the carpet in the truck bed. I pulled off the sill plate cover and placed a line of silicone sealant along the lip where the truck bed and rear bumper cover come together. This runs the entire width of the truck bed. With that silicone sealant in place my truck bed was 100% dry after some major rainstorms.
Hope this helps someone else, because it consumed about 10 hours over a two week period of time for me to get all of the leaks fixed.
Rough image of the seam I'm talking about needing silicone sealant. I'm posting this since another site member was having this same problem and I didn't take a picture of the seam with the sill plate off.
The place in the attach image where the silicone sealant was necessary is at the seam pictured just to the front of the bumper cover bolts shown as removed in the image.