Melting/cracking rear tail light lenses on 355 (and 360/550/575/575SA)

Okay, we all know of this problem, and if you open up the back and remove the bulb holders, you will see that the center, #7506 (21 watt) bulb is placed several centimeters closer to the center clear lens, than the outside brake and turn signal bulbs. That is the reason for the cracking/melting, the design of the housing is faulty, placing the bulb much too close to the clear lens.

If you put your car in reverse, and put your hand up to the clear section, you can feel the warmth immediately, and after 30 seconds or so the plastic lens is getting noticeably warm.

When I bought my 355 spider almost three years ago, I had new inner tail light lenses installed to replace the cracked/melted ones, and I have been ever vigilant to make sure to not leave my car in reverse for any more than necessary, being aware of this design flaw. Recently, I have noticed (in bright sunlight) the very faint traces of my lenses begining to show early signs of some heat damage...just a very slight discoloration of a 4 or 5mm section in the very center...but annoying. Granted the lenses are only $150 each from Ricambi, but the idea that these should be considered "expendable" every three or four years is silly. So, taking upon one of No Doubt's threads (what the heck is his real name anyway, and why is he so secretive of it? ) I searched for a suitable LED replacement. LED's are much cooler in operation, but have other "issues" related to color, intensity and sometimes electrical compatibility with "bulb out" sensors and such. Fortuntately the 355 does not have the "bulb out" sensor, but I was concerned that the LED replacement be of enough intensity to be seen by other drivers behind me, so they know I am backing up (I don't really think back up bulbs ever produce enough useful light to actually "see" by). Any way, LED's typically only project light in one direction, whereas an incandesent bulb goes in many directions (other than down). Here is what I settled on:

http://www.superbrightleds.com/specs/67.htm

Scroll down to the bottom of the page and see the "67-x15 with 1156 base". This has the same base as a 7506 bulb, and has a few unique features. One, it is shorter by almost 1cm from the stock 7506 bulb, so it will be physically further back from the lens. The other neat feature is it has 9 LED's facing out the end, but also 6 LED's arrayed around the base at 90 degrees to send light to the reflector, and improve dispersion and intensity. Note also, that a "white" LED is actually rather bluish, sometimes even a bit purplish. I am unsure what these will look like, but they claim they will resemble flourecent light, so a tinge of blue is my prediction.

Cost is around $19 delivered for two bulbs. I will take pictures before and after and post for you all to see. I am hoping this will be a more permanent solution to this issue.

Thanks ND for you perserverance in posting all your LED threads.

 

Brilliant !!!

 

Do you buy two or four? - there are four white lenses in the back.

 

But will they fit a wooden F50 ?

 

Dave, only the inner tail lights have the bulbs, so you would need to order only two. The outer tail lights do not have back up light bulbs in them. What is interesting, is I DO notice that occasionally, some cars have cracking/melting of the outer tail light lenses too, (though usually much less damage) and am unsure what might be causing this. Perhaps the brake light bulbs?

Hold on, wait until I post pictures, and we will see if this is a worthwhile upgrade.

 

Great info, thanks! finally an explanation of why my inner lenses are 'bubbles' and not flat. And here I was hoping I had some rare 'upgrade'

 

Because LED's are sensitive to the direction of the electric current, I had to switch the two wires going to at least one light socket (i.e. swap places with each other) in my tail lights in order to align the LED with the Italian current flow.

Standard light bulbs, in contrast, are *not* current sensitive (to direction), so the Italian wiring means nothing to standard bulbs.

However, unless you are fabulously lucky, you'll have to swap the two electric wires that go to at least one light socket in the tail light assembly when you install LEDs in place of the old light bulbs. Think of it as switching the + positive with the - negative wire (though that's really not always what is actually going on).

 

I dont know what you guys are on about....I never put my car in reverse and rarely use the brakes. These italian cars are made to go forward at high speeds and corner like their on rails. lol

 

D'Oh! So *that's* what I was doing wrong!




I'm not worthy!

 

Here's my bubble lens....

Wondering if that explains why my clutch wore out in 5k miles from the previous owner - he was always driving the F1 in reverse!!!
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........................thats the worst I have ever seen...!!!!!! 300 bucks for new ones from Ricambi or search for them on ebay....!

 

Yikes!

 

That bulb was actually burned out too, I suppose from the overheating. Just to point out that even the Big 3 get it wrong...check out the Chrysler 'cloud cars' 3rd brake light (Stratus, Cirrus). Ours blew twice, melted the plastic. On the road at least half of these cars have 3rd brake lights out.

Now for replacement...are these lenses pretty much all identical? I've seen some on Ebay but they weren't the exact same P/N (but sure looked identical, front and back). Just for fun I may actually try to 'fix' these lenses by heating and reshaping (no cracks or anything, just look round instead of square). Nothing to lose!

 

Jay, just get new ones. (btw, yours are the worst I have EVER seen! Congratulations!)

There are different types for the 355. There are discretely different between the inner and outer versions...the outer ones have no provision for the back up light. There are also "euro" versions I have seen listed, not sure what is different about those. Safest bet is to buy from Ricambi or your local dealer.

 

Here's my experience with LED's. I posted this recently on TSN (The Saab Network):

Re: LED Light Conversion
Posted by Erich (more from Erich) on Wed, 29 Aug 2007 22:38:03
In Reply to: LED Light Conversion, BZF, Wed, 29 Aug 2007 18:23:36
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I tried this myself. Almost all of the LED's are not as bright as the normal bulbs. All of them have a narrower viewing angle (they don't fill the lens with as much light). The brake lights and rear running/parking lights will cause a bulb failure message unless you use the resistors. The resistors get VERY hot and completely negate one of the advantages of the LED's----reduced electrical load. The use of the LED's for turn signals will also require load resistors otherwise they will blink too fast. I think you cannot use the special relays (at least on my car) because the blink rate is controlled by the SID.

I installed white LEDS on the interior, for the front parking lights and for the rear license plate. Without exception, every white LED failed after a short time (I checked my electrical system and voltage is within specs.). I contacted Superbright LED's and they said they would send me a postage paid return label. They never did even after repeated email contact. In addition, one time I ordered 3 amber LED's (25 bucks a pop!) and they sent me three white LED's.

I've re-installed the original incandescent bulbs but now continue to get the brake light failure warning every time I start the car. Maybe the circuitry got damamged.

I spent A LOT of money for their best LED's for all three of my cars. Overall I am very disappointed. Until LED technology, for these purposes, improves some more I would save my money and stick with what you have.

Erich

 

Erich, I had one red LED from SuperBright fail, too. The rest have been fine, though.

 

I have only had white fail. Maybe 10 bulbs and not all the same type (part #). I think white is the "newest technology" (although not new any more). You probably know that they use different substances/compounds to create different colors of light. I can only imagine that it's harder to produce LED's that give off white light or they would have had them decades ago (I remember blue LED's were a big deal when they were introduced a few years ago).

The superbright single LED reds were okay on my car for brake lights. Deeper red and almost as bright. A little loss of brightness while gaining the safety advantage of the attention getting quick on time is okay with me.

The big, ribbed metal bodies on the superbright single LED's make me think they're really pushing the limit reliability-wise. It appears the purpose is to be a really large heat sink. I don't mind paying $25 for one LED bulb but only if it will last the life of the car.

 

Nice toes.... lol

 

Can't afford shoes, saving up for my 355 major

 

So, the bulbs came today, very quickly I might add, from www.superbrightleds.com

Installation is quick and easy, as it is a direct swap (note to ND, I was apparently "fabulously lucky" as I just plugged them in, no rewiring required! ). Light pattern and distribution looks very similar and seems to fill the reflector and lens properly. The bulb is about 1 cm further back from the lens (good thing) and appears to produce little to no heat at the lens. I hear they may produce some heat at the bulb base, as they have some circuitry there, but that is not a concern here. I AM concerned with the report that these LED bulbs are not particulary reliable, and will have to wait and see on that. Hopefully, since back up bulbs are not on that much, that they will last acceptably in this application.

Two minor issues:
1) Bluish tint...it does resemble flourescent light.
2) Reduced intensity, appears to be 25 to 35 percent less. This does not concern me much, as I don't need the lights to "see" by, but need them bright enough to warn on coming drivers I am backing up, and these seem more than bright enough for that duty.

I did converse with Daniel Stern at www.danielsternlighting.com and he mentioned that one other option (staying with conventional incandescent bulbs) would be to substitute the stock 7506, 21 watt bulbs with either a Narva 17411 (15 watt) or 17511 (18 watt) bulbs which should also reduce the melting issue. He should stock them, and I would imagine they are much less expensive than the LED option, and possibly more reliable. My concern, is will they reduce the heat as much as LED's do? That question is not clear, and without purchasing a set, unknown.

On to the pictures:
First one is with stock 7506 incandescent bulbs.
Second picture is with left side LED, and right side with 7506.
Third picture is with both sides with LED bulbs.
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That white tint is a much better look for the reverse lights, and you've easily solved the heat/melted lense issue by using the LEDs.

I'll be interested to learn if they last appropriately.

 

Actually, the bluish tint doesn't look "right" to me. If anything, it resembles the color of headlights, rather than back up lights. I am unaware of ANY car at present, that uses LED's for the back up lights. So there could be some confusion from other drivers of what is going on. Not a bad thing, as the confusion would lead them to believe a car is driving head-on at them (at night maybe).

 

I also put white LED's in the interior of my 328 and it gave it a kind of hospital look because of the bluish tint. Did not go well with the tan carpet etc. Anyway, put the originals back in which returned it to the "warm" glow."

Bought a number of the tubular white bulbs for the licensce plate lighting etc. I think they use 9 small LED's on a printed circuit board. I would slowly start to lose some of the LED's. They would flicker some days and then eventually burn out. Probably a heat issue since I saw that the tubular plastic housing had little air holes on one side of the housing. They put those there for a reason.

When checking at night I found that on my 328 the back up lights with original incandescent bulbs put out a useful amount of light for backing up as opposed to just enough to let people know my car is in reverse. That was not the case with the LED bulbs.

The superbright LED's in the rear turn signal and brake light housings definitely did not "fill-up" the lenses with light like the original bulbs. It was very obvious there were two source of light in the circular housing. With normal bulbs it looked like a big ring of light and was brighter.

 

A couple more comments. One, if the brightness is a concern, I did note that www.superbrightleds.com does make a 24 bulb version, versus the 15 bulb version I bought. It still conforms to the size dimensions of the oem 7506 bulb. More expensive, they would cost around $31 for the pair, delivered, versus $19. This 24 LED bulb version also has the side mounted LEDs to uniformly fill out the reflector, like the 15 bulb version I purchased. I would still assume a brightness reduction over the oem 7506 bulb, but less so.
http://www.superbrightleds.com/specs/1157-x24.htm
It is pictured at the bottom of the page. Note that it is the same length as the stock bulb, so it is very close to the lens, but since it produces much less heat, should not be a concern.

It was suggested I take some IR heat readings off the light housings, comparing the oem 7506 versus the LED bulbs. I am on a business trip, but will try and post this information on Friday.

 

Their brightest bulbs (Luxeon) until recently, have only a single LED which unfortunately makes the reflector useless. I see they now have a 5 watt version with some extra LED's on it. Haven't tried the new one but it looks like it could be decent. Brighter and a wider viewing angle. Of course it uses more power but still a lot less than incandescent. I would definitely try these if I had melting lenses! $30 a pop but lenses aren't cheap either.

I'm sure you'll see a big difference in heat readings... 7506 vs. LED