Help! With rear window seal and seal channel rust - PeachParts Mercedes-Benz Forum

McScott · #1 09-15-2015, 03:55 AM

Hi

I am new to Mercedes-Benz and diesel cars for that matter.
I just purchased a1983 240D. Its in pretty good shape but the rear window seal is baddely cracked. Their is no visible rust around the outside of the rear window but their are some rust/water stains on the rear of the headliner. When i gently poke at the headliner I can feel crunchy stuff for lack of a better term.
I have read horror stories about the seal channel deteriorating to nothing. If the channel is bad is their any way of telling without pulling everything out? All I really need is some words of encouragement.

Thanks

rocky raccoon · #2 09-15-2015, 06:54 AM

The only thing you can do is pull the window out, repair the channel and replace the seal with new.

NOT a death sentence. I had to do the same with my 1983 coupe. In my case, I had to be careful with the rear windshield and the new seal was $$$$ since both are very difficult to find for the coupes.

Any competent body shop can repair the channel. The cost for me was about $300, plus than the cost of the seal. Sounds like yours may be in worse shape than mine was so may be a little more. I also paid additional to have a glass shop R&R the rear window since I didn't want to take any chances. Your rear windshield is much more available so long as you don't insist on OE, as is your seal.

I think you can get away for less than $1000. Well worth it if you like your car as much as I do mine.

Check your trunk. It has been getting water incursion also through that seal. Pull your left and right side trunk liners out and check for rust under them. Mine had some minor rust-through that I fixed myself with a sloppy fiberglass job since it was out of sight. Replacing the rear windshield seal will fix that too.

t walgamuth · #3 09-15-2015, 08:54 AM

I'd go ahead and probe all around the window to see how bad it is. If its just surface rust you might get by for some years by lifting the rubber edge, cleaning well, applying rust binder, then paint and finally caulking with black silicone. Doing it "right" as described by rocky can be very expensive.

leathermang · #4 09-15-2015, 09:44 AM

I believe this post by Charmalu is good info ..

"""well in the FSM Volume 2 under windows sec 67 it details how to properly
install front and rear windows. for the front window, it is installed dry, and then under#19 "Between glass and sealing frame, and between body and
sealing frame, seal with MB window sealing compound".
for the rear window as per #16 "Make seal between glass and rubber frame as well as body and rubber frame with MB window sealing compound
part# 001 989 31 20".

I took out my rear window last summer because of a leak in the trunk. the
gasket had been in their 9 yrs, time to replace not going to mess with it.
bought a new gasket, had window cleaned ready to install. called a mobile guy to install. charged $150.00, put it in dry. said MB doesn`t use sealant
so when the winter rains arrived I needed a bilge pump in the trunk.
I bought some 3M window black urithane sealant. fits in a cailking gun, ran
a bead under the rubber from the center of the roof down to where the corner of the trunk meet. then between the glass and rubber. dry the
rest of winter. I think the tube was $14.00.
charlie """
from
http://www.peachparts.com/shopforum/diesel-discussion/195480-re-seal-windshield;-do-yourself.html

McScott · #5 09-15-2015, 09:06 PM

Thanks for the information everyone. I discovered that the"crunchy" stuff is the foam padding in the headliner that has hardened.

And yes Rocky I love my car to the point where I'll spend money on it to get it right. But still I am on a budget.

DeliveryValve · #6 09-16-2015, 01:13 PM

Quote:

Originally Posted by leathermang

Quote:

Originally Posted by charmalu

well in the FSM Volume 2 under windows sec 67 it details how to properly
install front and rear windows. for the front window, it is installed dry, and then under#19 "Between glass and sealing frame, and between body and
sealing frame, seal with MB window sealing compound".
for the rear window as per #16 "Make seal between glass and rubber frame as well as body and rubber frame with MB window sealing compound
part# 001 989 31 20".

I took out my rear window last summer because of a leak in the trunk. the
gasket had been in their 9 yrs, time to replace not going to mess with it.
bought a new gasket, had window cleaned ready to install. called a mobile guy to install. charged $150.00, put it in dry. said MB doesn`t use sealant
so when the winter rains arrived I needed a bilge pump in the trunk.
I bought some 3M window black urithane sealant. fits in a cailking gun, ran
a bead under the rubber from the center of the roof down to where the corner of the trunk meet. then between the glass and rubber. dry the
rest of winter. I think the tube was $14.00.
charlie

My previous windshield was replaced by Safelite Glass many years back. The seal recently gave up was cracked all over. My intention was just to replace the seal, which I bought from MB. But just so happened that on one of my yard visits, I found a car with a really good condition newer windshield and seal. My Safelite windshield had road blasting, so I decided to replace them both.

Removing the glass and seal on the donor car was a dream. It all popped out nicely. I couldn't asked for a better experience.

My car in the other hand, was a nightmare. The Safelite Tech urethaned the seal to the glass and the channel. What a pain the arse it was to dig that seal off, clean the channel and get it ready for the new to me seal. (I decided to reused the donor seal because it was in such great shape.)

I put a bead of plumber's putty on the channel and slip roped the glass around. It went in nicely. When I do need to remove this windshield again, it should pop out nicely as well.

Just saying for a DIYer, I am not a fan of urethane sealant use in our cars. What a pain it was to clean up. Stick with the MB putty or plumber's putty. You'll thank yourself later if you are personally doing the replacement again!

.

Stretch · #7 09-16-2015, 01:24 PM

Under the metal work between the liner there is also a lot of sound deadening foam - that might also feel crunchy so don't panic just yet.

Be careful when removing the trim - kill the old seal in preference to killing the trim.

Here's more information

PeachPartsWiki: Rear Window Seal Replacement

leathermang · #8 09-16-2015, 02:29 PM

Quote:

Originally Posted by DeliveryValve

...... The Safelite Tech urethaned the seal to the glass and the channel. ......

He may have been required to do that. Some cars are engineered to where the glass is part of the strength in a roll over.... and good contact between the glass and the seal...and the seal and the car is required....meaning for instance... that it may be required that a specific cleaner is used on the glass immediately before the urethane and seal are applied...
I got this information from a very helpful 3M regional representative. He gave me a bunch of free samples and an inch of tech information on all sorts of 3M stuff......
3M rocks on so many of the things we need for our cars....

DeliveryValve · #9 09-17-2015, 11:47 AM

Quote:

Originally Posted by leathermang

He may have been required to do that. Some cars are engineered to where the glass is part of the strength in a roll over.... and good contact between the glass and the seal...and the seal and the car is required........

It could be true, but I am going to side on the fact that they are covering their arse to make sure they don't have to come back for a redo.

.

leathermang · #10 09-17-2015, 03:31 PM

Quote:

Originally Posted by DeliveryValve

It could be true, but I am going to side on the fact that they are covering their arse to make sure they don't have to come back for a redo..

Does the FSM not call for a sealant ?
sealing compound......part# 001 989 31 20 ....
What is wrong with not wanting to have to come back for a redo ?
As long as they are following the Mercedes instructions ....

rocky raccoon · #11 09-17-2015, 03:41 PM

Generally, MB engineers the sealing surfaces so that no adhesive or sealant is required. I have replaced seals on my trunk, sunroof, doors and convertible top (R107) and have never used a sealant or glue. The channels accept the rubber seals and hold them tightly without leaks so long as they are clean and not rusted.

IRT windshields, I think (?) they are designed to pop out in a frontal collision. If so, sealing them in place is counterproductive.

leathermang · #12 09-17-2015, 04:14 PM

Quote:

Originally Posted by rocky raccoon

Generally, MB engineers the sealing surfaces so that no adhesive or sealant is required. I have replaced seals on my trunk, sunroof, doors and convertible top (R107) and have never used a sealant or glue. The channels accept the rubber seals and hold them tightly without leaks so long as they are clean and not rusted.

IRT windshields, I think (?) they are designed to pop out in a frontal collision. If so, sealing them in place is counterproductive.

" Generally"... ?? What does that have to do with the specific instructions from the FSM which Charmalu posted ?
Do you have any references for ' designed to pop out ' windshields ?

DeliveryValve · #13 09-17-2015, 04:24 PM

Quote:

Originally Posted by leathermang

Does the FSM not call for a sealant ?
sealing compound......part# 001 989 31 20 ....
What is wrong with not wanting to have to come back for a redo ?
As long as they are following the Mercedes instructions ....

I do believe you misunderstood me. I am not saying that they should not use a sealing compound. In fact, I think they should use CORRECT compound.

But I am against using URETHANE on the seal. The correct MB sealant will not harden and stick like urethane. The Safelite folks go with what is easy for them, and that is to shoot a bead of urethane with their battery powered caulking gun.

.

leathermang · #14 09-17-2015, 04:40 PM

Sorry, I am also for the correct sealing compound.
Most other cars urethane is the gold standard.

McScott · #15 09-20-2015, 02:48 AM

Thanks for the information! I plan to tackle mine a week from Thursday