1963-1966 antenna mount spacer for underside of fiberglass; zinc or y. dichromate?

[Gary B.]

Does anyone know which finish is more typical of factor production for the antenna mount underbody spacer (I think it’s GM 3824493) that resides on the underside of the fiberglass? LIC used to sell a spacer that was clear zinc. The current repro sold by all the common vendors has a yellow dichromate finish. (Although MidAmerica sells one that is bright chrome, which I can’t believe is correct for an underbody part.) My gut feeling is the clear zinc is correct, and the yellow dichromate is NTP. But that’s just a guess, and I’d prefer to hear from an expert.

Gary

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[Keith B.]

Re: 1963-1966 antenna mount spacer for underside of fiberglass; zinc or y. dichromate

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from a NOS antenna assembly made sometime in the mid 60's

[Gary B.]

Re: 1963-1966 antenna mount spacer for underside of fiberglass; zinc or y. dichromate

Keith,

Thanks for the photo. The spacer looks a bit grayish to me. Like zinc with an aged patina. It that what you see?

Gary

[Keith B.]

Re: 1963-1966 antenna mount spacer for underside of fiberglass; zinc or y. dichromate

from what I recall it was a diecast metal like a pot metal with a green/ grayish phosphate finish.

[Gary B.]

[Keith B.]

Re: 1963-1966 antenna mount spacer for underside of fiberglass; zinc or y. dichromate

Well to be honest I took that picture six years and the antenna was installed in the car three years ago. I kind of forget.

[Gary B.]

Re: 1963-1966 antenna mount spacer for underside of fiberglass; zinc or y. dichromate

Keith,

I found photos of two unrestored originals. The spacer on one looks like cast metal with an as-cast or gray finish. The other looks like there might be traces of yellow dichromate. No clarification there.

Gary

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[James W.]

Re: 1963-1966 antenna mount spacer for underside of fiberglass; zinc or y. dichromate

I had my antenna restored by Gregg Thompson. The spacer came back dichromate.

James

[Gary B.]

[James W.]

Re: 1963-1966 antenna mount spacer for underside of fiberglass; zinc or y. dichromate

Gary,

No previous pictures of the antenna spacer. My car has a dealer installed luggage rack. That is a rubber well nut you are seeing. The original owner in Dallas, TX. ordered it installed when it arrived at Steakley Brothers Chevrolet in Dallas in mid July of 1965.

James

James,

Do you have a photo of the spacer from your antenna before restoration? I’ve seen other antennas that Greg Thompson has restored, with the dichromate finish on the spacer, but I still wonder if that finish is what GM spec’ed. it’s now so easy to buy the dichromate finished spacer and use it as is in an a restoration. But it it right? There were so very few yellow dichromate items on C2s, e.g., brake master cylinder cap, PB booster, so that’s what makes me question it.

And I have to ask, what’s that black rubber(?) and yellowish threaded do-hicky on the fiberglass undersurface, above the tail lights? Is that for a rack?

Gary

[Alan D.]

Re: 1963-1966 antenna mount spacer for underside of fiberglass; zinc or y. dichromate

Here is the original from a Mar64 car, hope some help

[Gary B.]

[Alan D.]

Re: 1963-1966 antenna mount spacer for underside of fiberglass; zinc or y. dichromate

The spacer and main mount (usually has mast on it ) both show signs of bright metal showing, like the dichromate was worn off,
so my guess would be for dichromate.

[Gary B.]

Re: 1963-1966 antenna mount spacer for underside of fiberglass; zinc or y. dichromate

Thanks for your help, Keith, James & Alan.