Replacing Rear window seal / gasket on a 82 Mercedes 300D W123
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- Опубліковано 10 лют 2025
- I'm not sure if this is called the rear window, or rear windshield? Either way, both the front windshield and rear both use this gasket seal setup, and it can be a real challenge to replace.
You WILL need a helper for this, as you will want pressure holding in on the window while someone else pulls the rope to slip the seal groove onto the body of the car.
I did these on my Grey W123 several years ago, and it stopped some leaks I had, and has been fantastic ever since, so it was time to do it to the Blue car!
I used URO brand seals, I have heard some folks question their quality, but I have personally had excellent success with their products on several cars I have owned so I bought them again for the Blue car.
Here are the products I used to do this:
➡Paracord: amzn.to/3BNhlnt
➡Rear window seal: amzn.to/3BPn5gq
➡I also did the front window seal which is the same process: amzn.to/3LZEOq3
(Links on this channel may be affiliate links, which earn me a small commission for referring you to a product, it doesn't cost you a penny, and helps me keep making these videos)
Here are the products I used to do this:
Paracord: amzn.to/3BNhlnt
Rear window seal: amzn.to/3BPn5gq
I also did the front window seal which is the same process: amzn.to/3LZEOq3
(Links on this channel may be affiliate links, which earn me a small commission for referring you to a product, it doesn't cost you a penny, and helps me keep making these videos)
Enjoy watching your w123 videos. Always learning something new about the w123's.
I've got so many more awesome things I can't wait to do to my car, as well as some half finished ideas and videos I need to finish up on it lol
George is very involved! Thank you for the video,Greetings from a fellow W123 owner in Johannesburg.
He's a great helper. Always has some kind of opinion on what I'm doing. Glad to hear from other folks that are enjoying these marvels of engineering!
I have never done this job but I am told it's easier to install the trim in the rubber before installing the window in the car.
I too envy your rust-free lower lip surface.
I've heard the same thing, and maybe I did something wrong but putting the trim on the window and rubber made it impossible for me to install into the car. I've done it 3 times now, but once the last seal gives up I'll try it again using that method!
Absolutely no rust on that lip, you're extremely lucky !!
No kidding. I'm beyond thrilled with my current "fleet", The blue W123 is so good. I need some paint and cosmetic stuff, but its so good. My work trucks, everything is so clean. Factory paint on frames, I couldn't ask for better stuff. I need to investigate the undercoating on Blue though, I know water can get in some places and cause trouble down the road, I need to address that before it bites me.
Excellent job. You explain it all nice and easy. Love it.
Your videos will help a lot to maintain my Mercedes-Benz w126 300sd 👍👍👍
With kind regards
Helmer
Thank you very much! We've certainly enjoyed our W123s, and they just keep giving, Glad to help another enthusiast keep their car around for many years to come!
'85 300CDT here. Good video!!
I’m having trouble getting the trim in once the seal is on and window is in
It is miserable sometimes, a good warm day helps, or a nice toasty garage, and some dish soap or soapy water helps everything fit back together good, but even then it can be a nightmarish endeavor
Awesome. Thanks for sharing.
George was of great assistance. You need somebody who yells and gets people moving.
Nothing would get done without him, and there would be a lot less naps being taken without his help.
Love George!!!
He's the best little mechanics helper around! 😄
Great video
Glad you enjoyed it!
The paste is the product they put on the rope , gives lubricant when pulling the rope out to bring the seal into position , they may have used copious amounts .
Well they really slathered it on thick on my car! Man that stuff was everywhere!
Any video on putting in the aluminum trim?? Thanks.
I haven't made one, it is a real chore, lots of patience, soapy water and absolutely no weaponry like hammers or axes (not even rubber mallets or dead blows!) despite how much the fight putting the trim back in makes you want to use such tools 😂 One day I'll probably end up making a video about it, but for now I'm just happy I got it in eventually.
You need to put the trim on before you put the glass in. It’s easy once somebody tells you the order. I’m stunned you got the trim on after the glass was in. That’s really hard. Don’t ask how I learned all this.
@@pacodrake3766 that was my thought too. I did the front glass with the trim installed into the rubber and I can not imagine installing trim separately...
I plan to replace the window seal gasket (actually all of them just to make sure) on my 82 240D. Would you have done anything differently in hindsight, or would you do it the same way. I appreciate the video.
I had great success with this method, I've heard some people say you're supposed to reinstall the aluminum trim before rolling the gasket into the cars body but I could never get that to work personally.
I'd do it the same way I did, but I did mess up one trim piece because I got impatient, so I would plan a little more time to take breaks and avoid getting frustrated with trying to reinstall the trim.
@@trythistv I appreciate. I will give it a go. I got the seal kit for the car. I have my son to help, and Winston our cat to make sure we stay on course. Thanks again.
Mercedes actually sell a window sealant glue, to use or not to use ?
Doesn't need any glue or hermetic or silicone ?
How do I change the windshield for Mercedes w126? I couldn't find an explanation of how to change it. I hope it will benefit me. Thank you very much.
The front windshield on a W126 is glued in with a urethane sealer like this: amzn.to/48SNbOM
This is very common on modern cars, pretty much any car has a glued in seal, changing them yourself can be done but can be very tricky too.
I have done it before, but I would be very tempted to have a glass shop do it, I'm not sure if safelite does cars like ours, but they have been reasonable and had good results on my newer vehicles.
I probably did mine wrong in my 1985 300D. As I recall, I first fit the rubber gasket to the body, then worked the glass into the rubber. Your method was like I did with my 1965 Dart rear window - first glass into rubber, then work rubber lip over body's pinch-weld, using rope-trick. Perhaps better. For that, I didn't put rope in the bottom of the gasket, only started on the sides since you can set the glass down with the gasket's groove over the pinch-weld, then gravity keeps it down as you pull the rope (and gasket lip with it) out the sides and top.
I've been told that I did mine wrong, Some people say you are supposed to put the gasket on the window, then the aluminum trim in the gasket, then rope trick the entire assembly into the car, I've never been able to get that to work, so I very carefully and patiently work the trim in after the window is in place. I think the key is, do what whatever works!
@@trythistv On older U.S. cars like my 1965 Dodge Dart, the front windshield has a plastic "lock strip" which you press into the outer groove in the rubber gasket as the last step. I assume the aluminum trim on the M-B is similar, but it isn't flexible so installing that way can bend it, plus hard to work it in the groove at the rounded corners. Would be interesting to see a video of how M-B did it at the factory. In most older U.S. vehicles, the rear windshield is installed as: gasket over glass (w/ sealant bead), then combination only body (w/ more sealant) working the inner rubber lip over the metal pinch-weld using the rope trick and/or prying. Outer stainless trim goes over and outside the rubber gasket, which keeps it from rolling outward to let the inner lip pull free. The 1990's up design of windshield glued to body using elastomeric sealant is much better. Indeed, for some popular classic cars I've seen kits to modify the body to allow such glass installation.
See thats what I thought, the trim would expand the seal and lock everything into place, but some people have told me you're supposed to do it the other way. My way worked for me. I'd like a urethaned in window, they are a little less prone to needing any kind of service unless the glass breaks.
Did you get the trim back on? I did mine a while back and still have some trim that doesn’t want to go back. It is literally killing me to try to figure it out. If I can get it with soapy water and patience I will keep trying. I saw an article after I installed the window that said I needed to install the trim before putting the glass back in. Well it was too late when I was done to do that!!! Nice video and as always I enjoy the great instructions.
I've heard it both ways, In my experience trying to put the trim in beforehand just made the window not fit, and bent my trim like a pretzel.
A VERY hot day (100F or above) and lots of soapy water in a spray bottle and I got it all back in unharmed, it did take me walking away several times as I got frustrated and wanted to use implements of war on the trim, as long as I stuck to waiting for the seal and everything to be nice and toasty between attempts after a few hours I gradually got it all back in without any harm done.
@@trythistv thanks. I am going to give it another shot this weekend and see if I can get it to go as long as it gets hot enough tomorrow.
@@DangerDIY I usually install trim before installing glass into vehicle. Takes patience and effort but our company has replaced few of these now and successful installs every time 👍🏻
You are supposed to put the aluminum trim in the seal before you put the window back. It is basicly impossible to get it back now.
See, I've heard that, I tried it on one window I did, and ended up with completely mangled trim. The other 3 of these seals I've done I very carefully installed the trim after the glass and seal was in, on a good hot day with lots of soapy water and never bent a single piece.
I'm not sure if I did something wrong with the trim in before popping the window in method, but it sure didn't cooperate for me.
@@trythistv I tried one window whitout first putting in the trim and it turned in to a completa mess. Especially the corners are hard, bordering to impossible to get in. It was alsow on a hot day, using soap and a Mercedes original rubber seal. Im also quite sure the originla service manual states that you should put the trim back in the rubber seal before you befor you put the windshield back in the car. But I guess everyone is free to do it their own way.
Interesting since I think it is termed "lock strip", at least in old U.S. cars which suggests it goes in last. But true that it is very hard to work it fully in at the top corners. I recall putting the trim in last in my 1985 300D rear window, without too much trouble or bending it. But, in a front windshield, I found it almost impossible to get in at the top corners.
how did you push in chrome trim back on ??
With tremendous care, patience and a lot of soapy water.
I think you forgot the silver insert that is not possible to install AFTER you put the window in :)
I've put the trim on after putting the seal in 5 times now, tried 3 times to do it before installing the window the way everyone says to do it, one time that ruined the trim, so I went back to putting the trim in after the window and seal is in.
Just takes some patience and care, has worked for me very well, but to each their own!
(3 different cars, front and rear on 2 w123s, just the rear on a w116)
@@trythistv that is great to know. So you can still insert the aluminum trim into the rubber AFTER you install the rubber and the glass into the car opening??? How did you do it? Just by pressure or hammering it in with a rubber mullet??? It should make the process easier to install it afterward.
A rubber mallet would destroy the trim if you smack it, that stuff is so thin.
I used a lot of soap, soapy water and gentle pressure with my hands on a very hot day, at times using something like a rubber mallet but not hammering, just placing the rubber part on the trim and gently pressing on it to spread out the pressure from my hand.
The trim is incredibly fragile, but I have never been able to install the trim before installing the window and seal, have had success with a lot of patience afterwards though!
george is great
Install new trunk rubber and lube with synthetic grease ,leak gone ,been there done that Mercede s 240 too 300 best passenger car ever made.
We drive ours everywhere, so smooth and refined in the highway, keeping up with the water leaks will keep stuff from rusting from the inside out so I try to keep on top of it, I'll certainly be checking my trunk seal!
What about the Chrom trimm?
The chrome trim is the tortuous task that requires a lot of patience, time and soapy water to make it easier to install.
Great videos I am buying a 123 1977 230 great CARS, THANKS . (GASOLIN)
W123 light
Issue is getting the panels on after
I never had an issue with them, but I hear lots of people do, I never could seem to do the install the trim and then the window method, maybe I'm just totally backwards but this way has worked great for me doing front and read glass on both of my w123s
0 use vac operated handles get at Harbourfrt.,I love (best brand ACE silicon 100%) all surface must be free of oil dirt ,clean with denatured alcohol.seal all rubber to metal car window frme. ,old German seal paste could be old chernobyl wax from factory
Man I wish I had thought of that back when I did this, I have one of those handle things too, Brilliant!