Replace Rear Window Weatherstrip

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72 Fastback - 351C-4V, Fitech EFI, T56 Magnum 6 Speed
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Thanks Don. I had seen that. It was mostly written up 10 years ago so thought it was fair to ask in case anything has changed or there were better options for parts, sealers etc. Also just a lot easier for me to process stuff like that while seeing it which is why I asked about the video.

 
I haven't done one yet but will be in about a month once I get my headliner in. I do know that the easiest way to get the window out is to take a utility knife and cut the weather strip at the edge of the window. You can then remove the window easily without having to do any prying.

 
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Dude,

Do yourself a favor, buy the best gasket available from Don @ Ohio Mustang and have a professional install it with the proper adhesives, caulk, sealer, etc.

I had a tech from Safelite do mine after the first one I installed myself leaked and its perfect....

Thanks, Jay

 
I totally disagree with what they did. WAY TOO MUCH SEALER. All you need sealer for is to fill the small irregular areas in the metal flange from spot weld distortion. If you hammer and dolly this area and grind any rough areas it does not take much. Him putting that huge bead of sealer in where the trim goes is why it is so difficult to get the trim off and on. 

I get my sandpaper and stuff from this place lots of places to get stuff. https://www.autobodytoolmart.com/searchnxt.aspx?keywords=glass%20install%20tools

You will see they sell tools for removal and install both. You also need a trim removal tool to lift the clips enough to let the trim lift out. Never force the trim should come right off when you get the clips loose. I use only plastic trim removal tools or wood dowels ground down around the glass. The clip tool is steel but never touches the glass.

Like someone stated I would cut the old rubber seal out. Daniel Carpenter usually makes the best rubber parts. I am not sure if he makes ours.

With the glass out it is obvious you need to clean glass and the channel on the body. I would never use the foam tape the factory used. 3-M is down to one windshield sealer that does not harden. The video showed him using 3-M strip calk in the rubber channel for the glass. It is too thick and I just make a tiny hole in the end of the 3-M sealer tube and put a tiny amount in the channel that the glass goes into. A helper is always good to hold the rubber as you put calk in and slip on the window. No rush needed as the sealer does not harden.

After you get the body cleaned up and fix any rust if you can find you are ready to put the string in the channel like he shows but no sealer in there. 

With your helper you sit the bottom edge of the rubber over the bottom edge in the window opening. You can put some sealer along the bottom before putting it in place. Small bead is all you need inside the rubber channel that fits over body.

When you are looking at window install tools the only metal one you might want is a hook to work the corners with. I use a woodruff key puller to pull just the corners in as someone pushes from outside. 

Pull the string and push the window in. No rush just go slow and if the rubber gets hung on flange use your hook tool to flip it over. Once you get it all pulled in go around the outside and push and massage the rubber into place. 

Now with your helper take the sealer and lift up the rubber where it is on the metal and put a small amount around the entire frame. You do not want gobs of sealer just enough to fill in any small gaps. 

Depending on how tight your car is you can actually do an air check with soapy water. Put air hose inside the car with everything closed up you can and let it blow in the car. squirt some soapy water around the gasket and look for bubbles. If your car is a rust bucket do not even try if nice and tight should work. That is how I found the roof rail leak on my car when brand new. 

With the trim off you can polish it if you want. Now go around the opening and every place there is a clip put a small piece of masking tape so you will know here they are. Install the trim should not ever use a rubber hammer should snap right on with finger pressure only. The bottom trim just goes on with screws. You should have checked and cleaned all your clips while the window was out. 

I would expect one tube of sealer would be plenty he said three which is crazy. Pic is my 73 showing the tape marking where the clips are. 



 
Excellent info, thanks much for putting that together. I actually laughed out loud at the idea of pressurizing the inside of the car. Between weather stripping and my Swiss cheese firewall you could set off a bomb in that thing without breaking a window.

 
They are pretty swiss cheese by now but some are still tight. I know that if you have a sun roof today and blow the air bags it will blow the sun roof out if all windows are up. Happened to a guy I know with a Mark VIII Lincoln. 

When I was working on a 69 Ford van I had I could not push the windshield out. I went to Ford dealer and talked with shop foreman. He laughed and told me to sit in the seat put my feet on the inside of the windshield and push one corner out while someone worked the rubber. It came out then just knew it was going to break but it did not.

 
Update - I finally went ahead and had someone else do it. I had to replace the windshield anyway so figured I'd have them do the back at the same time. Found a guy that does a lot of classic cars and seemed to know exactly how to do this. I removed the window myself and cleaned up and prepped the frame to seal it and make it smooth. Told him what I know about this from reading here and he basically waved me off and said he's got this.

Sure enough he had the window installed in about 15 min. After he's done I ask when I should check for leaks and he tells me the next day. So next day I run out with a hose and it's leaking worse than with the almost 50 year old rubber that had giant chunks missing.

He's coming back on Friday to try and fix it. I'm pretty sure his plan is to squirt as much goo as possible in the gap around the seal. He really wants to do the molding at the same time as I suspect it'll be tough to work with once there is 8lbs of sealer in there. I don't want to put the molding on yet as I need to try and straighten it and have it gold plated (joke) before it goes back on. That and it will be easier to wrap the car without the molding on there.

So other than leaving the clips exposed, any advice on how to handle this? I suspect that if I tell him I want to start over that I'll need to pay again since I provided the weatherstrip.

Thanks

 
Did he use the foam tape of just pull the rubber seal in?

If he used the foam tape that sucks in my opinion. There is only one sealer I would let him use and that is 3-M I will go get the number from catalog. The way to put sealer in is to have one person lift the edge of the rubber seal with a plastic trim tool or wooden dowel ground to a wedge. As you lift the rubber the other person applies a small amount of sealer between the metal flange and the rubber seal. He should have put a tiny bead of the sealer in the channel for the glass before he put the rubber on the glass. 

There is absolutely no reason to fill the area around the rubber up with sealer. Like you said you will not be able to put your trim back on. You should not have to hit the trim just push down with your finger. 

Here is a link to the type sealer used for rubber gasket sealing.  https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Auto-Bedding-and-Glazing-Compound/?N=5002385+3293194048&rt=rud

If he pulls out a tube of urethane windshield glue he does not know how to install glass with a rubber seal. If you put urethane in it sets up and glues it all in and you have to cut it out. The correct material does not harden.

This is the MSDS from 3-M. 

https://multimedia.3m.com/mws/mediawebserver?mwsId=SSSSSuUn_zu8l00x4xt9P8295v70k17zHvu9lxtD7SSSSSS--

 
Thanks for that. I wasn't able to watch everything as I was trying to work while he was doing his thing. But I'm thinking he used the same urethane he used to seat the windshield. He laid a bead of it around the base and the window was narrower than he thought so there is a part on the edge that missed the sealer. He knew this and told me as much. Told me he'd come back and fix it when I do the trim. The more I think about this the worse it is and I should have made a bigger deal about this at the time.

So now I need to figure out if I try and make this work and live with it or pull it out which will of course be an even bigger pain than pulling the old stuff out. And then I need to pay to do it again more than likely.

 
Windows today do not install like they did back then. Ford used to tape to get the messy liquid sealer off the line. If it leaked the dealer fixed it. You can read the info on the 3-M material it is currently the only thing they sell for doing the job. Years ago they had three different ones. Chemicals and ingredients get make unsafe so it keeps changing. 

If he has already glued it in just do not let him fill up the channel with stuff that does not do the job. You can get a tube and do it if he does not want to make right. You can show him the info on the 3-M material not just an opinion this is what you use...

 
I just sent him that info and told him that it looks like it was done wrong. I'm pretty sure i know the answer to this, but if it was done wrong, there is no fixing this, right? Basically new rubber and start over with the right stuff?

 
Well crap. He actually did that already with the urethane. So the rubber is glued to the glass. It leaks about half way up one side that in both lower corners

 
It might not be set up yet. The CJ videos should be banned. They tell you to get three tubes of sealer and fill it all up. They are IDIOTS. I put my first window in with rubber gasket in 1967 and I have never used half of a tube and no leaks. I do not work on GM or anything but Ford. The leak areas are very small and takes very little to seal them that is why they had the rubber gasket.

Don't stress over it but if he does not want to use the correct material send him on his way and find someone that knows the older cars.

 
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