Armored Lights Bulb Problem?

[Gypsyman]

Since I have the reverse light switch mounts done I've been trying to decide on reverse lights for my rig. I really liked the look of the armored lights with clears lenses on the rear of the Deuce so I went ahead and ordered a pair. Something that I found during my search is concerning though. I ran across a LOT of armored lights with perfect outer protective lenses and broken inner bulbs. This was on both NOS and used lights.

Sure enough, my two NOS armored lights show up and one of the inner bulbs is broken. Zero signs of damage to the lights. They barely even show handling marks so they are as close to new as one can get.

Does anyone know if this is an issue with this particular light style/design? I just can't wrap my brain around how the inner bulbs can be breaking with no damage to the outer protective lens. Could it be a design flaw and maybe the lenses touch causing a pressure point? I don't see it being heat buildup caused by the outer lens because many of the broken ones are brand new like the ones that I received.

Thoughts?

 

[G744]

Probably some mook running the lamp retainer screws down too tightly. A hot day, the lamp expands, then cracks.

Don't forget those have two filaments, low & high beam. It picks up a ground thru the mounting bolt.

DG

 

[Gypsyman]

I'll open one up for inspection tomorrow. My plan was to use the low beam for reverse and the high beam on a second wire and manual switch as rear work/loading lights.

 

[rustystud]

Probably some mook running the lamp retainer screws down too tightly. A hot day, the lamp expands, then cracks.

Don't forget those have two filaments, low & high beam. It picks up a ground thru the mounting bolt.

DG

What he said .

 

[G744]

On most trucks, pin "K" on the trailer receptical is hot +24.

You can pull that wire out of the loom in the cab, and switch it there. Tap into it at the rear for your light.

 

[Gypsyman]

There's definitely a minor design issue with these particular lights. As you can see below the glass sealed beam lamp only makes contact at 4 small locations with the housing. My guess is that these small contact points cause stress risers in the glass bulb until you end up with what I have. A break that is clearly from contact point to contact point. All of the lights that I ran across with broken bulbs had this odd angled break. Now I see why. It also explains why you rarely see a fractured protective out lens. The out lens has 360° mounting surface support front and rear.

I'll be applying some thin adhesive backed felt or foam to these mounting surfaces in the hope of reducing the pressure points to some degree.

Now to track down some replacement GE 4811 bulbs.

 

[Gypsyman]

On most trucks, pin "K" on the trailer receptical is hot +24.

You can pull that wire out of the loom in the cab, and switch it there. Tap into it at the rear for your light.

Thank you for that info G744. I'll add that information to my installation notes.