Nicole

It happened again... That's the third time I experience this, on all three 928s I've owned...

Moisture starts accumulating in the right tail light. Where does it come from? It's always a crack in the housing, right above the brake/tail light, underneath the backup light. It must be getting hot in there...

I never found a good, lasting fix for this, though. It's hard to clean the area, and what glue or other material would withstand the temperatures from a brake light while sitting at a light? Maybe someone has a suggestion on how to fix this properly and so it lasts for a while...

At the same time I discovered that the two outer brackets on each of my tail lights are lose. They wiggle around and rattle a bit. I don't remember this from previous 928s and wonder, if they have been mounted incorrectly after the FO (first owner) had the bumper cover removed, painted, and replaced. Do those brackets wiggle or rattle on your cars?

Drmark

Interesting Nicole - your brake light is double filament, mine in my 95 GTS is single and I have no signs of heat damage (even though it's an auto and I'm on the brakes for long periods in traffic).

Nicole

S4 and later tail lights for Europe (and probably rest of world) were different. I think you guys have a rear fog light that we don't have, and the bulb arrangement is different.

Brett Matthews

Hi Nicole,
Interestingly, I may have a similar, or not, problem/observation; Although it doesn't seem to be inside of the tail light assembly, I have water BETWEEN the lenses. And this is on my left unit. It is more than 3/4 full-looking!

I was concerned because of the water grounding out the bulb, so I removed the unit, pulled the bulb, up-ended the unit, and no water came out! And now, moisture is accumulating in the right unit, again, between the lenses.

No Idea how to get it out of there, either...... Can't find how it is entering
Brett

IcemanG17

Nicole
How about bondo? Body shops have been using it forever? It should seal up the crack no problem, I just don't know whats is heat resistance is?

borland

You can seal those cracks from the outside using silicone sealant (RTV), just make sure you clean and dry the area before applying the sealant. RTV is good at high temperatures.

There's a vent hole between the harness connector and the bulb, shows in your first photo.

Those plastic brackets just keep the wires in place during the lense install, so they can flop around without being a noise problem. Mine do, but you can, with the correct screwdriver, drive the screws in further.

I'm pretty sure the bumper skin bracket are a later S4/GT/GTS feature, as I don't recall seeing them on my 90' S4. Just a slot in the bumper cover that accepts the lense. Adjustable bracket seems like a nice idea.

BTW, I replaced both my lenses with new ones. After selling the old ones on eBay, net cost wasn't that bad. But mine weren't cracked like yours.

borland
90' S4, Slate Metallic

SharkSkin

Brakes -- why would you want to be on the brakes?

Seriously though, step one is obviously to repair the cracks. JB weld would be a better choice than Bondo or RTV if structural strength is required. Also, if you look around a bit, you should be able to find hi-heat reflective paint, preferably silver, that you can use to help reflect the heat from that plastic. Also, maybe you could paint this onto the bulb itself, so that heat is not thrown to the side but only out the end. Paint beginning at the base of the bulb and on up past the filament, leaving the end of the bulb unpainted. These two measures ought to help preserve the plastic housing. IT's very easy to try and if you don't like the result, just chip the paint off the bulb or replace it. Also, you might be able to glue bits of aluminum flashing from the hardware store over the portion of the inner housing that overheats.

Nicole

I did some cleaning on this area today, and realized that the brown stuff you see in the above picture is glue from a previous repair attempt. So, I used cotton swabs and cleaned the area with aceton, then applied this magic high temperature silicone - I hope this will "work" with the material, if the brake light ever gets too hot again.

The downside is that there is quite a bit of dirt inside the tail light housing, and it will be hard to wash it out. Not sure, if it matters once the light stays dry - one might never see it.

But dirt in MY car??? Just kidding...

Pfunde

........epoxy........

Nicole

That's what the brown stuff was. Didn't hold up to the heat.

BrianG

And here we have that elusive 2-element brake-light bulb, again! Nicole, would you do me a favor and check your outboard tail light bulb to see if it is also a dual element? It should be the one on the (opposite side to this brake light) left side of your car.

By the way.... do both elements in that brake lamp light up when you step on the brake?
Have you discovered what DOES light up the other element?

JoeTaylor

Nicole,

Sorry to bring up an old post, but after reading what you said, I examined my passenger side tail light (brake light) that is constantly getting wet from rain or carwash and failing, and found what you described.

I was out to dinner last night and my 928 was caught in the rain and on the way home the brake light failed. This morning I checked the plastic lens above the brake light bulb with my finger and inside it was bumpy, somewhat melted and obviously cracked. There was no water trapped in the lens, so I assume its only dripping on the hot brake light bulb, popping it.

What solution worked for you? RTV silicone sealant? More epoxy? Painting the top of the bulb with reflective silver paint? Replacing the brake lights with LEDs?

I would like to fix this for good, if there is a fix.

Thanks,
Joe Taylor

White Lightnin'

While LEDs would definitely run cooler than incandescents, I have opted to stay with the regular bulbs... for now.

I had the same cracks over the brake light bulb and used JB weld to seal them up. Then, I used some super glue and glued aluminum foil over the crack (shiny side out, or facing bulb). Hopefully, this will provide some reflection of the heat and prevent the cracks from getting larger.

I have yet to perform this mod to a new lense to see if it keeps cracks from starting... but it might!

77tony

Preventive maintenance. Just switched to the Superbright LED 1157/45 and they do run much cooler than the incandecents. JB Weld or epoxy will fix it. T

safulop

Nicole, that silicone is good up to 500 degrees, so it should work. Both my taillights are a tad loose, one more than the other, but I have not bothered to check why. I could possibly just tighten something, I don't know yet.

-Sean