Best Adhesive for Lower Windshield Rubber

[emerydc8]

Over the years the rubber seal that runs across the bottom of my windshield seems to have hardened and isn't making a very good seal. I don't even think this piece is available anymore Any suggestions on the best adhesive to keep the seal tight against the windshield? I tried superglue, but it doesn't seem to work very well.

 

[Whitemamba23]

I used a black windshield/glass specific silicone and it works great. I sourced mine from a local auto glass shop.

 

[emerydc8]

Thanks. I'll look for it this week. In the mean time I'm trying this Permatex Clear RTV Silicone I found in my garage The challenge is to find things to stack and hold the rubber seal down while it cures. I suspect the guys that replace windshields all the time have stuff that cures quickly.

 

[speedy300dturbo]

The silicone would be a good choice because it can be peeled off the rubber seal (which is now NLA) without damage. I would advise against using windshield adhesive (3M window-weld or similar urethane products) because they'll bond too aggressively to the rubber. Attempting to pull the seal out after it's been bonded with urethane would likely tear it before the glue separates.

 

[daantjie]

3M Bedding and Glazing Compound.

 

[emerydc8]

3M Bedding and Glazing Compound.

Thanks. I'll look for it. Have you used it on the W124?

 

[sheward]

For holding weight on items while waiting for adhesives to cure I use bags of rice, sugar, etc. For more weight use large freezer bags or garbage bags with oil dry, sand, or water.

drew

 

[geraniumtr]

I've done this several times on my 94 E320 which has the one piece seal. I've had good luck with a tube of ordinary trim adhesive. Make sure both the windshield channel and seal are clean and dry. Apply in several spots; you don't need to apply a bead the entire length. Make sure you press the seal into the channel its entire length. A plastic trim tool helps. I use several pieces of painters tape to hold the seal in place till the glue drys.

As others have pointed out don't use any type of permanent adhesive.

Regards,

Peter Weissman

 

[gsxr]

Jon, you can buy a new aftermarket lower channel, click here, Precision Replacement Parts WLM F740. Usually, the problem is the old channel is broken or stretched, and doesn't "pinch" the rubber tightly enough to hold it in place. MB doesn't sell the channel separately, it's sold only with a new windshield.

Before I learned about the aftermarket channel, I needed to glue the rubber to the glass on our beater E420. I used 3M auto glass urethane #08693 (click here) and it worked great. Still stuck tightly years later. However, I don't know how well it will peel off the rubber when I need to remove the weatherstrip next time. I hope it doesn't destroy the rubber gasket as @speedy300dturbo warns about.

Next time I'm trying the PRP aftermarket channel, I hope it works.

 

[Vinnie]

Alternative solution may be to try to soften the rubber as per this howto:

HOW-TO: Re-soften hardened mirror boots | "HOW-TO" Tutorial Articles

Hello all around, first of all, please allow me to introduce myself: I am Willi, 55, from Leverkusen which resides in the middle of Germany, between Cologne and Düsseldorf. I am owning a 1991 500E which is undergoing restoration currently. I am a long time reader in this forum and today I...

www.500eboard.co

The only major problem I see is that the magical Mesamoll component seems to be hard to obtain in US, and I'm not sure about shipping options from Germany. That's why I'm giving it as alternative solution, which at some point may be useful - for example when one may want to remove the whole wiper mechanism for giving it a service.

 

[emerydc8]

@gsxr - Thanks Dave. The old channel is broken in just a few places, but this isn't where the seal isn't sitting flush with the window. The bottom part of the seal is held by the lower track -- it's just that the top part is lifted up, I think this RTV I used will hold for now, but I have another car that's doing the same thing so I'm just looking at the options. I appreciate everyone's input.

 

[gsxr]

Jon, double check to make sure the root cause isn't the channel attached to the bottom of the glass. This is the primary channel which retains the weatherstrip, and when it isn't gripping tightly, the rubber does not stay against the glass.

There is a separate, lower, thicker channel for the bottom edge of the weatherstrip at the drip rails. This portion is generally OK.

It's a RPITA to get this weatherstrip design properly seated!

 

[emerydc8]

Thanks, Dave. You may be right. I was thinking the channel beneath it is made of plastic, but it could be rubber that just got so hard that pieces of it broke off. The Permatex seems to work but I don't know what I'll do on the other car. Have you ever replaced the lower channel? There's no picture of the channel at the Summit link you provided, but for $26 it may be worth a shot just to see if that would fix a lower rubber trim that has hardened over 25 years.

 

[gsxr]

Jon, the glue-on channel is plastic with aluminum core around the upper section that attaches to the glass (see photo below). The lower section is non-reinforced plastic, which spreads/stretches over time and no longer pinches the rubber tightly enough to retain it. Eventually the plastic breaks as well.

I bought a couple of the WLM F740 channels from Summit (along with some oil, to get free shipping) but have not yet installed one. You'll need to remove the windshield wiper to R&R the channel. I think some urethane adhesive may be needed to glue the channel in place, although you might want to test-fit everything before gluing.

 

[emerydc8]

Thanks Dave. Having dealt with the blower regulator issues on both cars so many times, I think I can get the wiper system removed in less than ten minutes! Is one channel all I would need per car?

 

[gsxr]

Thanks Dave. Having dealt with the blower regulator issues on both cars so many times, I think I can get the wiper system removed in less than ten minutes! Is one channel all I would need per car?

Correct - one channel per windshield.

 

[emerydc8]

My curiosity got the best of me and I decided to have a better look at this lower windshield channel. A significant portion of my channel is broken on the driver's side, but it doesn't look like you can easily get the old channel out from under the bottom of the windshield because it's glued. Has anyone tried this with the windshield in place?

 

[gsxr]

Jon, it may be difficult to scrape off the old channel, but it should be possible... not sure what tool(s) would be best for this.

I believe if the previous installer didn't go nuts with adhesive, there shouldn't be interference from the main urethane bead. Even if the surface isn't perfectly clean underneath, as long as the channel can be fully seated, that's all you care about.

 

[gsxr]

@emerydc8 - Jon, did you ever try using the replacement channel?

 

[mikeym]

Basic question: is the channel/weather seal needed to keep the water from getting into the interior or are they designed to shed water away from the bottom of the windshield into the drains… I think it is the latter but wanted to confirm…

 

[gsxr]

Basic question: is the channel/weather seal needed to keep the water from getting into the interior or are they designed to shed water away from the bottom of the windshield into the drains… I think it is the latter but wanted to confirm…

It's the latter. Sheds water from windshield into the trays below.

Interior should be sealed by the butyl adhesive for the glass-to-body, although all rubber grommets that pass through the firewall also need to be intact as well (and, the foam drip tubes below the heater box).

 

[emerydc8]

@emerydc8 - Jon, did you ever try using the replacement channel?

Hi Dave,

I don't know how I missed your post for six months. Sorry about that. No, I haven't dealt with the problem, but I probably will soon as my windshield just cracked after I used the washer on a hot windshield. Actually, both windshields are now cracked on my cars, so I'm thinking of taking the wiper assemblies and trims off both cars before the mobile replacement guys come out to the house. I have to order two of the channels from Summit first. It's one of those nuisance cracks, out of view, that I could live with, so it's easy to put them off until later. I'm sure you can relate.

 

[asultan]

Resurfacing this thread to get some pre-facelift questions answered if anyone does have answers...

Given the work I'm doing now (seen in my owners thread) I removed the battery tray to find some standing water unfortunately. I've already been in this area a few years ago and POR'd it. I've seen other threads about using a silicone or mild urethane sealant to seal the windshield rubber to the windshield to allow the water to go over the trim as intended and into the drains. is that the only option?

I've always thought the windshield drain design on these cars was really shitty honestly, and for the amount of water egress required, a 1"x1.5" (not even) Square Hole on either end of the windshield just doesnt do it lol. Yes theres the center cowl drain as well but it just doesnt add up in my eyes.

 

[gsxr]

The windshield "rubbers" are only an issue for late cars - facelift, and very very late 1993 USA model year. Late cars where the 1-piece rubber won't stay put, need adhesive to attach to the glass, IF you don't want to replace the channel that retains the 1-piece rubber

1986-1993 cars have 2 separate trim strips which attach on each side of the monowiper via metal clips. Last I checked, these rubber-coated trims were still available new, if your old ones are bent or disintegrating. Snapped into place they should route water into the drip rails without issue.

The total water drained should be minimal under normal conditions - driving or parked in the rain, or washing the car with a garden hose. When the drains are not blocked, the system should work fine.

 

[asultan]

The windshield "rubbers" are only an issue for late cars - facelift, and very very late 1993 USA model year. Late cars where the 1-piece rubber won't stay put, need adhesive to attach to the glass, IF you don't want to replace the channel that retains the 1-piece rubber

1986-1993 cars have 2 separate trim strips which attach on each side of the monowiper via metal clips. Last I checked, these rubber-coated trims were still available new, if your old ones are bent or disintegrating. Snapped into place they should route water into the drip rails without issue.

The total water drained should be minimal under normal conditions - driving or parked in the rain, or washing the car with a garden hose. When the drains are not blocked, the system should work fine.

Even with new rubbers (my poor illustration) this isn't an issue? My rubber trim isnt severely warped and I find that at the edges, and the meeting face of the monowiper its always soot and dirt carried finding its way under these trims...

 

[gsxr]

Even with new rubbers (my poor illustration) this isn't an issue? My rubber trim isnt severely warped and I find that at the edges, and the meeting face of the monowiper its always soot and dirt carried finding its way under these trims...

When seated correctly, the trim strip should be pulled tightly against the glass, so dirt cannot get underneath. The trim strip appears to be a vinyl-covered aluminium section with a separate rubber seal along the edge of the glass. They can get tweaked with repeated R&R, and the metal clips also must be in good shape to hold it in place.

 

[Ascension]

I used a black windshield/glass specific silicone and it works great. I sourced mine from a local auto glass shop.

Same here on my 95 E420

 

[nehuge]

Here was my adventure doing this, not fun at all, especially getting the center curved part of the rubber seal to snap into the center curved part of the molding while same time getting the wiper motor assembly itself in place. There were some parts of the seal that just didn't want to click in so I had some 3m cladding tape and some gorilla glue brand of mounting tape (compatible with weather and outdoors) that I put under those spots to make sure no areas were sticking up.

 

[gsxr]

Nice work! Have you installed the wiper yet? Is the new aftermarket channel holding the rubber seal tightly?

 

[nehuge]

Yes, there were some parts of the seal that just didn't want to click in tightly, perhaps due to the rubber ridge on back of the rubber seal shrunk or little specks of it torn off, etc, so I had some 3m cladding tape and some gorilla glue brand of mounting tape (compatible with weather and outdoors) that I put under those spots to make sure no areas were sticking up.

 

[The Emperor]

Here was my adventure doing this, not fun at all, especially getting the center curved part of the rubber seal to snap into the center curved part of the molding while same time getting the wiper motor assembly itself in place. There were some parts of the seal that just didn't want to click in so I had some 3m cladding tape and some gorilla glue brand of mounting tape (compatible with weather and outdoors) that I put under those spots to make sure no areas were sticking up.

Nice work, my young apprentice.....

 

[nehuge]

Nice work, my young apprentice.....

View attachment 177145

The Force didn't feel with me at certain points lol

 

[asultan]

The Force didn't feel with me at certain points lol

finally i have found the infamous david c on youtube…

 

[nehuge]

finally i have found the infamous david c on youtube…

Uh oh, what'd I do?

 

[asultan]

Uh oh, what'd I do?

nothing! ive watched many of your videos while trying to fix my own stuff for reference! super useful, btw your comments are turned off on all videos i think?

 

[nehuge]

nothing! ive watched many of your videos while trying to fix my own stuff for reference! super useful, btw your comments are turned off on all videos i think?

Ya I turn it off as I get bombarded with so many questions I don't know how to even start doing anything with them lol

 

[emerydc8]

@nehuge — Thanks for doing the video. Very informative!

 

[gsxr]

Ya I turn it off as I get bombarded with so many questions I don't know how to even start doing anything with them lol

I had my videos set to require approval before comments are posted. Fortunately I get almost zero comments, lol. Dunno if YouTube changed the options/settings since I created the channel 10+ years ago.

 

[nehuge]

I need to:
1) stop mumbling in my videos
2) get my hand off the mic on my phone recording the videos so I don't sound muffled on top of mumbling
3) eradicate #2 above my getting the wife to film without tapping her foot impatiently. The wagon is her car BTW lol
But really though she appreciates the hell out of my part time second job keeping these cars going.

 

[The Emperor]

The Force didn't feel with me at certain points lol

 

[Rabelz]

I just finished removing the old molding (which had become brittle, decayed, and broken) along the bottom of the windshield. I have dry fit the replacement part that DavidC (aka nehuge) referenced. However, I cannot determine from the conversation or video if and what adhesive should be used to bond it to the windshield. Please advise. Thanks for all. Ron