During some of the recent heavy rains, I had a small amount of water coming in around the aftermarket window on the drivers side. It looked like the window had slipped down in the opening which compromised the seal somewhere along the top. The previous owner lived on a rough road so that might have been a factor.
When removing the window yesterday, I noticed another problem. The outside panel had been cut a little too big. I should have taken pictures but didn't so now I'll have to write about it...
The top edges of the cutout were even but along the bottom towards the front the outside was bigger by almost 3/16". The curved corners were a bit generous as well. I inspected the seal on the window after it was out and it was apparent that the window had shifted down and was barely sealing at the top rear corner. At least the cut edges had been rust proofed so thankfully there was none of that to deal with.
So first I whipped out my trusty tube of 3M Window Weld and filled the void between the inner and outer sheet metal all around the opening. Filling this area keeps the inner and outer panels from moving when the trim ring squeezes them together. The result is more even pressure on the seal. I let that cure for 24 hours.
Instead of using a replacement seal (which would have been too narrow for the over-sized cutout) I decided to use
.090" thick x 1/2 wide 3M VHB tape. I applied the tape around the window flange and pulled the backing off just along the bottom sill. I left a tail on the remainder of the backing so I could pull it off later.
I cleaned the outside surface of the van around perimeter of the window with alcohol. VHB likes clean surfaces. Then I masked that off and waxed the painted surfaces that would be hidden forever by the window.
We placed the window in the opening and while my wife held the window from the outside, I used shims to move the window up (~1/16") and then shifted it fore and aft to get maximum overlap with the body all around.
We had a little trouble when the VHB wanted to grab along the bottom but we could pop it loose easily enough and then continue to move the window around to get it "just" right. When it was all good, we pressed down the bottom edge, pulled the top of the window away from the van a little and pulled off the rest of the VHB backing. Then we pressed the window against the van. I put the flange back on and tightened the screws gradually in a crisscross pattern. I used the flange head screws from the previous post since they don't distort the trim flange near as much as the pan heads that were there.
Totally stoked when I went outside to look at how the VHB tape had responded. It's the grey stuff between the flange and the body. The slider door window doesn't leak but I may reset it with VHB also. I think this is going to be bomber -- but time will tell.