I went out for a spin in the dark yesterday, and noticed my left headlight wasn't working. Turns out the bulb I was using decided to eject the glass portion of the bulb. Since Ford didn't give the generic bulb number on his bulbs, it is my belief they are an 1158. Next is it true the new 1158 bulbs are not the same configuration? And no, I don't need to know about the new rocket science 50 cp bulbs! I'm after the 21-2 cp number.
At the time that the 4 digit number standard came into being, the Ford 21/2 by default became 1158. (From original era Mazda bulb replacement instruction sheet)
The March 1927 price list of EVEREADY MAZDA also calls for an 1158.
The issue you refer to is that the original design were tee-pee filaments, with one indexed 90 degree to the other...the current 1158 have flat horizontal parallel filaments.
This is where it gets dicey...(grin)...in theory the original critical dimension of the middle of the light source was 1.25" above the top of the brass mounting nibs if we use the original 1158 specification for the tee pee filament style...and the current 1158 specification calls for 1.25 as the light source center, even with flat filaments.
I'm not judge and jury...leaves you with a 'go figure'.
Here is a hint to prevent the old shellac seal from letting go like you experienced. Before an old bulb let's go, give the seam a dribble of super glue...it will flow around and seal better than the original shellac.
Something like these
Now THAT is teasing, Terry!
I did what you mentioned George. I got some Crazy Glue, and ran it around the base where the glass goes in. Hopefully the new bulb won't come out. I have a box of at least two dozen old stock bulbs that were out in the weather, and it's impossible to read the bulb number, and that is why I posted this. Thanks for the tip. Terry, thanks for the post. I've been wanting a NOS original bulb in the wrapper like yours for years. Maybe some day I'll find one. They go for big $ on ebay.
Larry, I, also have two new Tung Sol bulbs that are in a plain Tung Sol paper wrappers not marked with the Ford info, but when I removed the bulb, I found the glass was ink stamped with Ford script, but it wouldn't show up in a photo. Also, the ink stamped bulbs are smooth on the round end of the glass, but the bulbs in the Ford wrappers have a round 'bullseye' molded into the end of the glass. The soldered contacts on both bulbs are 'football' shaped, instead of just being round drops of solder.