Sab

I bought two new tail lights almost a year ago since the original lights where a bit faded and had water in them. Shortly after I purchased them one started foging up after driving or sitting in the rain. Now they are both leaking and collecting plenty of water. It looks really crappy. The shop initially told me I could return them and I hope it's not too late now.
But I remember reading a thread here, which I can't find now... That it is possible to reseal the lights. Does anyone have any tips in reference to that? Should I try to seal them or should I try to return them? They look new and don't seem to have any cracks.
regards,
Sab. <img src="confused.gif" border="0">

Big Dave

If you can't re-seal them properly, try drilling a small hole in the bottom so the water can't collect. I did this for one of my non-Porsche cars I owned in a previous life. It worked, and solved the problem of bulbs burning out because of the pooled water.

Greg86andahalf

Or, you could add fish. Maybe baby sharks? Might look cool at night.

Sab

Not enough water for a fish tank yet. LOL

dr bob

This topic did come up last year. Mark Anderson of 928 Int'l mentioned a service bulletin that has a procedure for drilling drain holes in the bumper shell, to keep water from accumulating there and eventially being sucked into the light housing. Like most procedures from the factory, it's very precise I guess (I haven't seen it). But it's a simple process of drilling three holes in the bucket at the low areas toward the front of the car ("back" of each bucket). I chose a handy 3/16" bit as big enough to let water out without getting plugged with anything that might end up in there.

I expanded on the procedure by adding a weatherstrip seal around the housing where it sits inside the bucket, out of sight from the outside. I used a 1/16" thick Arlon closed-cell foam seal, cut to 1/2" wide. It takes a long piece of this stuff, several feet for each lamp IIRC. Anyway, the gasket keeps almost all the water out of the bucket, and the drains get rid of any that does get through.

For the lamp itself, the biggest hole in the assembly is the place where the bulb holder inserts. On many cars there's a foam or neoprene gasket to help the seal there. I'd have to go pull a lamp assy to see if that's part of mine or not. Might be worth finding or fabricating one.


If there's a serious leak in the housing itself, you can find it by pressurizing the lamp housing a bit. I'd try this with the discharge of the shop vacuum first, and spray the seams with soapy water to find the bubbles and therefore the leak. The lenses are assembled by ultrasonic welding I suppose, or they might just be glued together. No matter, you can fix a leak with a low-temp soldering iron by just dragging the tip through the seam that leaks. The plastic melts slightly and the seal is restored.


So far the combination of drain holes and the gasket around the outside have worked well to keep the water out of that bucket. My primary reason for doing this was to get rid of the hard water stains that happen when car wash water dribbled out on the back bumper. Keeping the rain water out is a fringe benefit.


Also-

I'd be hesitant to dril any drain holes in the lamp assy itself. The reflectors in there are typically sensitive to water and will oxidize/rust of you aren't careful. Just a thought!


HTH!

Sab

Thanks Dr Bob,
I am sure that will resolve my problem.
regards,
Sab. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

Gary K.

Dear Sab,
I had that same problem with an '87 S4. I had success by THOROUGHLY cleaning around the edges of the bonding between lenses and frame, allowing it to dry well, then using the windshield sealant silicone that comes in a small tube. Just put a thin layer on, allowed it to dry (dries slowly), then re-installed. Had success in a similar way with one of the headlights on the same car. Sealed the bonded area between the glass lens and the reflector area of the headlight unit.
I've had success removing the water that is inside the taillights or headlights by either a slow flow of pressurized air, or by putting them very near a dehumidifier for a long period of time. DO NOT use heated air for the tail light, as that could cause the plastic components to "fog" from heat and high humidity.

Good Luck,

Andre Roodnat

Am I right that you are describing fluids within the unit? One of my tail lights is fogged up, but it’s in between the layers of plastic. I still haven’t figured out how it gets there. Seems like it condenses. I drilled holes at the bottom and used the compressor to blow the water out. But it never quite disappears and after some rain it is as bas as before. Anyone the same? How does it get in?

Sab

That is the exact same problem I am having.
regards,
Sab.

mickey chou