How to fix waterleak around tail light??

[66andBlue]

As long as I have the car I am trying to prevent water leaking around the left tail light into the trunk. In an earlier post Bob Possel suggested to replace the outside rubber gaskets around the light (#35 in the picture). Although this improved the problem it did not fix it totally. So here are my questions:
1.  How hard can I tighten the 4 nuts on the studs that protrude inside  to press the gasket as tight as possible against the chassis before I can do damage?
2. SLS shows the use of additional weatherstripping around the tail light. Has anyone used that strip and if so did it help?

My 230SL parts book doesn't show that strip so it may be something SLS is suggesting to cure a known problem.

I'd appreciate all your comments, thanks.

[Richard Madison]

Alfred:

Make sure the rectangular rubber gasket is properly seated inside the chrome surround of the light.

The light unit is held to the car body by large white round screw-ins. They should be finger tight against the light but not so tight that they split apart. The lower tightener (the one nearest the side of the car) can be tightened easier if the two electric plugs are removed first.

Make sure the light unit chrome surround is set flat and even against the body.

The rubber (plastic) strip belongs along the top of each light and a similar piece goes all along the top of the center chrome bar that sits alongside the trunk lock. The strip sits along the top of the surround and follows it downward to the end of the top edge around the corner.

The materail shown from SLS does not have the same profile as the original but seems it will do the job.

The original rubber strip is NLA from Mercedes or from the US parts places so let me put in a bid for a piece of your unused strip if you get it from SLS. One of my lights is missing the strip.

Here's a photo of one light with the strip and one without (Sorry for the jerky picture.)

Richard M, NYC  

Download Attachment: RearLT2.jpg
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Light unit with Strip.


Download Attachment: RearLT1.jpg
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Light unit without strip. The Left arrow is pointing to the strip on top of the chrome bar below the trunk lid.

[waqas]

quote:Originally posted by 280SL71

The light unit is held to the car body by large white round screw-ins. They should be finger tight against the light but not so tight that they split apart. The lower tightener (the one nearest the side of the car) can be tightened easier if the two electric plugs are removed first.

In three different cars, I've pulled apart the lights and found the rear lens section was actually attached to the body first with nuts and washers (on the same bolt stems). The interior lighting unit is then hand tightened with the white thumb nuts ON TOP OF the nuts and washers.

Although I've never been sure of what is original in this setup (the dealer parts manual doesn't show the nuts and washers-- just the white thumb nuts), I've always liked the idea of NEVER having to loosen the lens even when a light bulb is to be replaced. This allows it to remain seated once a good fit is found for it.

[66andBlue]

quote:Originally posted by waqas

In three different cars, I've pulled apart the lights and found the rear lens section was actually attached to the body first with nuts and washers (on the same bolt stems)...

Waqas,
that is exactly how they were mounted on my car (see picture) and that was my first question. How hard can I tighten these nuts? Obviously the seal on the outside is determined by the pressure you put on these studs.

Are 280SL lights mounted differently?

Richard,
I may have some extra weatherstripping and will check next week.  
This strip was never installed on a 230SL behind the trim next to the lock, or the lights, but I would give up "originality" if I knew that it makes a difference.

[Naj ✝︎]

quote:Originally posted by 66andBlue
that is exactly how they were mounted on my car (see picture) and that was my first question. How hard can I tighten these nuts? Obviously the seal on the outside is determined by the pressure you put on these studs.

Are 280SL lights mounted differently?

Same on my molested 280!!

naj

[scoot]

Interesting.   I recently purchased new tail light gaskets and found that the didn't compress nearly enough to prevent a gap between the car body and the chrome molding between the tail light and the trunk lock.  I never considered that there should be rubber in there, although it's possible....  I haven't noticed it on any other cars though....

[waqas]

quote:Originally posted by 66andBlue

...that is exactly how they were mounted on my car (see picture) and that was my first question. How hard can I tighten these nuts? Obviously the seal on the outside is determined by the pressure you put on these studs.

What I do is first fit the lens without the seal (carefully to avoid scratching the paint) and make sure the gaps are even all around the chrome trim. If the gaps are uneven, look for the source. If there is body damage in the area (old repairs, etc) then sometimes you can slightly twist the metal around the holes to allow the bolts to shift slightly to adjust the fit.

Once the dry fit is good, I place the rubber gasket and re-install the lens, evenly pushing it in, and then place the big fender washers and tighten all the nuts evenly. Once I notice the rubber gasket being compressed I stop tightening. Then I pour water around it to look for leaks.

I've never used silicone grease on any rubber, but perhaps that might help.

[bpossel]

Hi Alfred,

Careful not to tighten too much (what ever that means...?).  When I re-installed mine, I overtightened and I now have a slight dip in the chrome on each side   .
Bob

[paulr]

I use a tube of black bathroom sealant for these areas and sealing my tops. It's great because it just peels off when you want to open up the seal and smooths nicely with a bit of spit or washing up liquid if it's to be permanent.

[mdsalemi]

The problem with silicone grease (products such as Dow Corning 44 and similar)is that it is extremely difficult to remove entirely from surfaces; so, if the surface you wish to paint someday has any invisible silicone grease residue, the paint won't adhere.

This is a long standing and well known characteristic with silicone greases, and most will have some kind of disclaimer (probably echoed by the Classic Center) "avoid contact with painted surfaces" or "avoid contact with surfaces TO BE painted".

[66andBlue]

Thanks for all your suggestions.
I'll assemble the unit again today and after performing Waqas' water hose test will report back with the result.

[scoot]

quote:Originally posted by mdsalemi

...
This is a long standing and well known characteristic with silicone greases, and most will have some kind of disclaimer (probably echoed by the Classic Center) "avoid contact with painted surfaces" or "avoid contact with surfaces TO BE painted".

The Clasic Center recommended talcum powder for getting tail light seals to fit in better.....    I haven't tried it yet.

[waqas]

quote:Originally posted by scoot

The Clasic Center recommended talcum powder for getting tail light seals to fit in better.....    I haven't tried it yet.

You'll notice a thin layer of some kind of powder coated on all rubber items (bushings, seals, etc) when bought from Mercedes. In fact, there are many instances in the BBB where it is recommended to coat a particular bushing with talcum before installation.

[J. Huber]

quote:Originally posted by 66andBlue



Richard,
I may have some extra weatherstripping and will check next week.  
This strip was never installed on a 230SL behind the trim next to the lock, or the lights, but I would give up "originality" if I knew that it makes a difference.

Regarding Richard's info -- we had a discussion years ago about the rubber piece behind the rear chrome. Earlier cars did not have it as Alfred mentions, but it did come later.

In my case, my original tailights (and the rear chrome between) had no rubber. However, my "new" taillights (10 years old now -- Miller's I think) do have the extra black rubber strip.

[66andBlue]

quote:Originally posted by waqas

... Once the dry fit is good, I place the rubber gasket and re-install the lens, evenly pushing it in, and then place the big fender washers and tighten all the nuts evenly. ...

Hello Waqas,
I owe you a beer at the next PUB.  

Doing the dry fit first I noticed a significant gap between the chrome trim on the outside lower left front edge. What helped closing this gap was to tighten the lower left nut first, that pulled in the edge. Next the upper left nut which pulled in the remaining vertical part [see picture on the left]. After that I tightened the other two nuts and did your hose test. Voilà- no leak!

But now I do need to install that strip behind the chrome trim that connects the light with the lock since the rubber gasket is clearly visible.  There is too much of a gap between the trim and the paint. See picture on the right.  (I put a piece of paper underneath to show the gap more clearly)

James, yours probably has that strip because the replacement lights are 2-component units as the good Dr. pointed out in the earlier discussion:  [http://sl113.com/forums/index.php?topic=1350].
Did you also add the strip behind the chrome trim?

[waqas]

quote:Originally posted by 66andBlue

Hello Waqas,
I owe you a beer at the next PUB.  

Looking forward to it!   Then I can start repaying you (and everyone else) for all the help I've received...  

[scoot]

I'm still thinking that this molding is just plain wrong.  Is that possible?  The "old" gaskets seem to cause everything to be flush, including the molding between the tail light and the lock.  The new gasket is just much thicker, or so it seems to me!

[J. Huber]

Hey Alfred, no I have not added the center rubber piece. It just never made the priority list... however, as I looked at it today, I can see where having it would add a nice detail across the chrome.

[Richard Madison]

I'm easily confused by something as technical as a strip of rubber but when I compare the strip in the parts diagram to the piece on my car, I see a difference.

The one on the car (maybe original??) has a "bead" shape along the top of the light, a kind of half round profile. The strip in the parts diagram seems to be flat along the top.

Here's a (poor) photo of the light unit with the "bead" strip and the strip on the chrome bar next to it. The piece on the top of the light is rounded while the chrome bar strip is flat.

So maybe the new strip is a replacement with a different profile...might work to keep out water but in my case it won't match the older strip. I believe the rounded older strip is NLA. I guess a new strip could be put on both lights to have them look the same.

Download Attachment: RearLT2.jpg
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Light unit with Strip.

Richard M, NYC

[66andBlue]

And to complicate matters further, the strip that SLS sells for the tail lights is NOT the same that they sell for the trim piece.



Another possibility is to buy p/n 000 987 73 70.  This is a part used to seal the fender moldings on a 112 coupe/cabriolet against the body. In contrast to the original part it is a plastic that is both stiffer and perhaps a bit thicker. But it is still available from MB at about $6 - 7 per meter.