I don't recall ever seeing a 1157/6 led replacement unit that was (IMHO) brighter than
a regular bulb. I think the contributing issue is that they cannot fit enough "lens type"
LEDs within the diameter profile needed to fit through a hole in the taillight housing
originally using 1157 bulbs. In addition, if the 3mm or 5mm epoxy cast leds that are cast
into clear epoxy are used (as all I have seen are..)they are intended to focus a beam for
each individual led of 10-30 degrees, plus your taillight lenses are not designed to be
used with narrow beam leds but a more unfocused filament type omnidirectional bulb. Faced
with the same issues rebuilding my ford f250 pickup, I have opted to 1) buy larger
"arrays" of leds (like aftermarket 3rd lights stripped down to the basic board and
leds/resistors) By carefully removing the back of the housing from the front using either
with a super sharp utility knife or dremmel with a mini cutoff wheel follow where the lens
and back of the housing are bonded together. After separating the two halves mount the
larger arrays with screws and epoxy on the housing, test the unit side by side with a
conventional setup and verify that: 1) they are brighter than stock by a considerable
margin. 2) that you have wired the arrays to the correct (former) socket pins, making sure
to check turn signals (insuring you have the "led compatible" flashers as a previous post
suggested). When you are satisfied everything is to your taste, carefully route the new
wires from the arrays down the back of the taillight assembly on the inside and have them
exit the back through the original 1157mounting hole. I intend to sacrifice a 1157 bulb
break the glass and drill out the bayonet end of the bulb and simply have the wires feed
through the hole with the 1157 brass bayonet already locked into the assembly, the final
step is to seal the exit hole with waterproof RTV and attach a compatible male/female plug
arrangement to connect the lights to the wiring harness, seal the seams of the front and
back halves of the taillight assemblies using either epoxy or acrylic cement. When the
seams are cured you have a sealed custom taillight assembly tailored to your own
expectations, it should not require component replacement inside the sealed unit since the
leds will likely outlast the car, however in the event there is a failure access to the
interior of the assembly would be to re-sever the front/back seam. This approach allows
you to utilize the entire area of the taillight assembly interior for more led arrays
which one can double or triple the light output, cant the outer arrays allowing wider
light dispersion to the sides as well.
I have already used this approach to replace my under hood light, cargo area interior
lights, except since there weren't off the shelf white arrays available I fabricated them
using perforated prototype circuit board to solder the leds to. In the case of my under
hood light I used 13 leds to provide noticeable improvement over the small (#194?) light
bulb that had surrendered to the harsh environment previously. The quantity of 13 was the
maximum I could fit inside of the plastic housing/lense of the original assembly. I was
even very conservative on the current that I configured them to use, operating them at
just over half of the max current spec for those leds. Works great and given the cost of
ultra bright output leds it was a reasonably economic change (about 10$ if I had to buy
everything). LED's can be used to outperform conventional lights BUT don't consider them
a 1 for 1 equal, it takes many leds to exceed the light output of large filament
automotive type bulbs like the 1157's or 2157's, etc. Proper led configuration, however,
gives you a brighter assembly that produces less heat and will last longer than most of us
will live.
Hope this is useful to someone out there, email is the best mechanism to contact me if you
have any further questions. regards, Joe.
On 26 May 2005 23:55:34 -0700, chudwuh.TakeThisOut@hotmail.com wrote:
>I need some advice from folks who have experience with halogen
>headlights and halogen and/or LED taillights. My car is a 38 Plymouth
>street rod with original light buckets all around. The headlights have
>been converted to sealed-beams using 2D1 bulbs and the taillights have
>been converted to use 1157 bulbs. I'm thinking of replacing them with
>equivalent halogen bulbs or halogen headlights/LED taillights. Of
>course, the goal is to see, and be seen, better. But before I plunk
>down $50+ for a set of bulbs...
>
>1. Are halogen and LED that much brighter than incandescent?
>
>2. I've heard halogen builds up a lot of heat - might that be a
>problem in the metal buckets? Their volume is a lot more than the
>bulbs take up but there's not much way for heat to escape.
>
>3. I've also heard light from LEDs is only visible head-on. The bulb
>would be aimed at the lens - prismatic red glass with "blue dot"
>center. Which is better in this case - red or clear LED?
>
>4. Would I have to change anything else - turn signal flasher, brake
>light switch, etc? I have a 552 flasher and a GM-type hydraulic brake
>switch.
Joe Brophy
CountryTech Computer
email: pcfixr.TakeThisOut@spiretech.com
>> Stay informed about: Halogen/LED Bulbs? 
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