[gtobully]

Folks - I installed a used high-beam T3 headlight in my ‘67, only to have it start fogging up, or smoking inside when turning on the head-light. Any reasons why this would happen?

Thx, Rob

[Greg Reid]

Probably got a crack in it somewhere. Just a guess. Sealed beam lights only work in a perfect gas filled vacuum...or something along those lines.

[dataway]

Over the years they lose vacuum where the electrical contacts pierce the glass in the back. No or reduced vacuum means almost instant failure. I've tested about a dozen used or NOS originals, about 70% of them smoke up on the first use.

[Jeff Hamlin]

50+ YO used bulbs aren't worth the hassle,
it's hit or miss and the weak (yellow) output sux if you drive around sundown/night.

I have been using these for decades with little/no issue;
https://www.lectriclimited.com/lighting-fuse-flashers

JM2C
Cheers.

[77 Canamman]

I have had about a 50% failure rate with old sealed beams. Before buying them, I require them to be tested.

['ol Pinion head]

In testing nearly a dozen NOS '68-'71 T-3 low beams, only have had one that tested bad. all but three, I removed from NOS headlamp mtg panels, at least a 45 years old parts stock. Need to go through remaining milk crates of used T-3's, am sure there will be chunkers.

[Chief of the 60's]

Coronavirus... Get another one.

[SRR]

A friend of mine says to put a drop of super glue on that pinch point on the back of the bulb.