Leaky Rear Window - '66 Newport

[darth_linux]

So, after many months of speculation, I've now confirmed that my rear window leaks water into the trunk. What to do?

I can see that someone, at sometime in the past, did some sort of repair to the seal, as some black rtv-like substance can be seen, but no other details are available.

I'm guessing that I need to remove the stainless steel trim, and then use something like a clear windshield RTV sealant, or perhaps the black 3M weatherstrip adhesive to go over the seam between the glass and the metal? Not sure how to proceed, but I know that many of you have been here before and know what the next steps are. Thanks in advance for your advice!

 

[Big_John]

I've used Permatex 81730 Flowable Sealer a couple times. This will flow into areas rather than just sit on top of the window gasket.

I've bought it at Advance Auto but here's the Amazon link: Amazon.com

 

[halifaxhops]

Me I would pull the window and see if the metal lip is still there. Common rust spot. Sucks though....

 

[CBODY67]

There have always been the "flowable" sealers which are applied with a flex-shaft nozzle, usually between the glass and gasket. I'm not sure that works as well as it is billed to, from our experiences on another vehicle we have with gasketed glass. So determining if the water is coming from between the gasket and the pinchweld or the glass and gasket, or combinations thereof.

As to sealer, I would prefer the genuine, premium 3M glass urethane-style sealer. To me, if the flowable sealer can flow into nooks and crannies, it can also flow out of them with time? Just my theory.

In using one of the sealers, be sure to install it for a ways away from where the actual leak might be. especially if there might be a low spot involved. You want to stop the main leak, but also prevent moisture from seeping in from other adjacent areas, too.

In the mean time, find some black strip caulk and put some in the places where the glass touches the gasket and where the gasket touches the body. That could be s diagnostic shorter-term fix. A few popsicle sticks and/or similar round dowels with a tighter radius on their pointed end can work to tool the caulk into the gaps nicely.

Please keep us posted on your progress.
CBODY67

 

[darth_linux]

I watched the “new features for 66” video on YouTube where they talk about the new design of the rear window seal. Looking at the diagram in the FSM I really don’t understand how it all is supposed to go together and work. The water is going under the seal and into the vehicle, pooling up on the package shelf before it drains into the trunk. You can see where I’m pointing in the pictures below. I had a hard time getting clear pictures without glare, so my apologies for that.

 

[fury fan]

My 65 SF rear window had some mild rust issues (same rear glass/gasket as you have).
I've had good luck with this, it goes on wiht a small paintbrush (you supply it, IIRC it's not a brush-in-can).

BUT - you'll need to decide if removing the rear glass/gasket and cleaning/painting the metal pinchweld is a better plan.
This will also allow you to replace any trim-clips that are in poor condition.

But the biggest thing -
If you try to get sealant around the gasket while there is still a bunch of crud in there, you are asking for a poorly-sealing repair. It might actually trap moisture.
That stuff also often interferes or does not flow well around the clips anyway and/or can interfere with the trim installation.


If the trim hasn't been off for awhile, you'll find it pretty stubborn. There's a special tool for these clips, but I've found (on 3-4 different cars) that each clip might require its own technique/tool. Often you won't know what that technique is until the clip pops and the trim is free. Squirting WD40 under the trim at the clip might help a bit?

And BTW - if you use this Windo-Weld - plan on being at it for awhile, maybe an hour or 2 to get it brushed into place. I don't even know if you can get it under the bottom edge of the gasket (I only used it across the top/sides of a windshield).

 

[darth_linux]

So it turns out it’s not the gasket or seal, but rather some small holes in the metal in the trough at the bottom of the glass. I know there’s a proper way to fix this problem, but that involves way more time, money, and work than I want to do right now. I’m gonna look for a solution that involves something like clear caulking, designed for windshields to fill those holes. If I can get five years out of the repair, then maybe in the future I can do it correctly. Open to suggestions, thanks.

 

[darth_linux]

I made a video showing the condition of the seal and the holes I found in the sheet metal. Let me know what you think I should do. Stripping the paint, cutting out the sheet metal, and repainting the car are not currently options available to me.

 

[57fury440]

I would clean the rust as best as I could and then use some epoxy resin. You can cut and put some little pieces of the fiberglass cloth over the holes too. They sell it in kits at most auto stores. Ace hardware sells them too. It is only temporary but if done right should buy you some time.

 

[CBODY67]

For the short term, the sealer orientation might work well. I would opt for black, though. A more involved fix might open larger old wounds not suspected.

 

[darth_linux]

For the short term, the sealer orientation might work well. I would opt for black, though. A more involved fix might open larger old wounds not suspected.

I’m not sure the color would matter, the trim completely covers the area of concern. Is there something in the formulation you’re thinking of?

 

[CBODY67]

I’m not sure the color would matter, the trim completely covers the area of concern. Is there something in the formulation you’re thinking of?

From the earlier "clear" formulations, as they age, they can turn opaque and look flaky, even if they might be hidden by trim moldings. I just like black better for it being hidden well.

Just my preference,
CBODY67

 

[darth_linux]

So I decided to remove the spare tire from the trunk and get inside there and take a look at the underside of the lower window channel that’s below the rear window glass. Someone’s definitely been here before. They used a Silver putty. I’m guessing it was something like Alumalead or whatever it’s called. Several holes were filled with this, one hole was filled with a screw and then puttied over on the top side! On the driver side extreme corner where the package tray sheet metal extends through into the trunk and goes up underneath the trunk proper, there’s quite a bit of rot. I’m thinking if I can stop the flow of water getting into that area and then maybe wire brush it all and spray paint it with some sort of rust stopper. I won’t have to worry about it in the future. Here are some photos of the carnage.

 

[fury fan]

Clean/scrape as much rust out as you can, treat with the rust preventer of your choice, and seal with something.
I would use the brush-on stuff I posted earlier.

It should only get wet when you wash the car, right?
Use a leafblower or shopvac to get the water out of there after washing.

 

[darth_linux]

Well, 24 hours later and we are leak free. I did a very meticulous job of cleaning and prepping the paint around the areas that have the pinholes, and I applied some versachem super clear silicone gasket maker type 7, which I use successfully on my leaky front windshield, using a highly customized plastic spoon as an applicator. Not much to see from the photos, but I just did a water test and nothing got in through the holes into the package tray or the trunk area. Feeling happy!