Tail light bulb socket mods to make 'em work

[cbarge]

If England's Lucas system was the prince of darkness,then Chrysler came close to writing the book on bad grounds on our beloved Mopars.

Pretty much the majority of all Mopars of the 60's/70's used body for ground on the lighting systems for turn signals,park,and brake lights.
Ma also used potmetal,aluminum,and tin for the lighting housings with stamped in sockets.
The majority of lighting problems is when the sockets short out from years of exposure to moisture,and rust caused by dried out lense gaskets,or lost or broken lenses.
One bad socket can wreak havoc on a Mopar driver with wierd things happening.Popping fuses,or both signals light with only one on,or the light in the dash lights up,but the outside one does not,etc,etc.
So,when you have a complete rear tailight housing with one bad socket,with no repops in sight,and no good used ones around,what do you do??
I have a solution I tested and works.
Plus it is a cheap fix and when done nobody would notice any difference,and no more road rage from other drivers when your light work properly!!

 

[cbarge]

In this article,I will be using two different housings as examples for clarity.
This front turn signal housing is from my 68 Newport.
You can see the corrosion that caused it to drawback to the rear and kept popping the fuses every time I hit the brakes.

 

[cbarge]

Points chasers and correct resto guys may not want to see what's next.
But if you want your lights to work,there is no turning back from here!!
With a cutting wheel,I chop off the socket from the housing..

 

[cbarge]

With a cutting wheel make slots in the remains of the stamped steel socket.
A dremel with a cutting wheel also works.
Carefull NOT to cut into the housing!!!

 

[cbarge]

Then remove what's left of the socket from the housing..
Here you can see corrosion had set in between the two different type of metals which causes a bad ground for the bulb.

This housing has actually rotted away behind the socket and the bulb never worked right..

 

[cbarge]

Here is a twist-lok style socket that I will be using in this demonstration.
You can either grab a metal or plastic type socket for your favourite scrap yard or buy a new one dirt cheap at any parts jobber.
Make sure you get one that has an extra wire for ground--which will be an important detail in this mod.

 

[cbarge]

The plan is to modify the original housing to accept the twist-lok socket.
Scribe the housing where the notches need to be made into the housing.

 

[cbarge]

Using a dremel,notch the housing and the opening may have to be made bigger to fit the twist-lok socket...
Make sure to test fit often and grind a little bit at a time.
Too big and your priceless housing will be junk.

 

[cbarge]

When done,the socket should fit snug into the housing for a water tight seal.
In some applications,the bulb may not fit through the hole and have to be installed with the lense off the housing.

 

[cbarge]

For the ground,use the third wire and attach it anywhere to the body close to the housing.
This eliminates using the housing as a ground and no more headaches.

 

[cbarge]

The beauty of this is if your car is equipped with the optional cornering lamps,you just have to crawl under and twist the socket out to replace the bulb instead of completely removing the whole thing.
Ditto if the back of your front turn signals are exposed.

Hope this tech article is usefull and provide a piece of mind.
Cheers,Leaburn

 

[Tinman]

Nice job explaining everything! Almost like turn signal restoration for dummies!: )

 

[slantsixdan]

There's something large and important you're overlooking here: the focal length of the new socket isn't the same as the focal length of the original. That means the bulb is in a different position relative to the reflector and lens, and that means the lamp doesn't work anywhere near as well as it needs to for minimum adequate safety. The reflector cup and the lens optics are designed to "look" at a filament at one particular distance and in one particular orientation, to gather and magnify and correctly distribute the light at the right intensity levels through the right range of angles. You can get away with moving the bulb a tiny bit, like about 1/8" tops, before intensity nosedives. Then all you get is just the filament's own glow; the reflector doesn't catch much of the bulb's light so it doesn't get magnified and distributed. For the same reason, it's important to pay attention to the clocking (rotative position) of the bulb within the reflector. Match it up, so if the filament of the installed bulb was horizontal with the old socket (or vertical, 45°, whatever) it should be in that same position with the new socket.

There's nothing wrong with your idea from a functional standpoint, it's just there are details that have to be paid attention to otherwise it's "one step forward, one step back".

Take a look around (Echlin or Standard Ignition buyer's guide) and you can find new sockets that will minimize the amount of cutting and modifying to result in a good socket transplant.

(Also, while you're at it, clean the reflectors with alcohol, then spray them with readily available "chrome" spray paint, which is practically ideal for the task.)

 

[Big_John]

Interesting.... Orienting the filament makes a lot of sense.

 

[commando1]

We had to do those mods on 68 Caddies otherwise the next time you had to change a bulb...

http://forums.cadillaclasalleclub.o...on=dlattach;topic=125595.0;attach=49611;image

 

[cbarge]

Slantsixdan, The focal length detail was brought up to me before..
Thanks for mentioning it and it is rather important.
The sockets used in the photos were just spares lying around.
Having the buld out too far is worse than in too far.
Some types of bulbs used back in the day are no longer available (ie wierd cornering lamp bulbs for NY'ers' Imperials,etc) so we have to MacGyver another type of bulb that has the same brightness.

 

[Zymurgy]

That was an old but very usefully thread, something that I find very important is adding that ground to the chassis, as opposed to the pot metal casing. My back up lights have been on my to do list for nearly 2 years now. I will probably just install a similar socket, I already have a pair, but still useful without doing the mod.

I too have first hand knowledge of the Prince of Darkness, so I am used to dealing wiring electrical issues.

 

[slantsixdan]

Some types of bulbs used back in the day are no longer available (ie wierd cornering lamp bulbs for NY'ers' Imperials,etc)

No longer available from the local auto parts store, no. But that doesn't necessarily mean no longer available. Ask your friendly local automotive lighting nerd (send me bulb numbers).

 

[livininharrow]

i think slant six needs to burn another one, lol