separate antenna mast from base
Anyone ever separate a 1977 or similar antenna mast from it's base ...without destroying it ??
Thanks as always
Michael B.
Thanks as always
Michael B.
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Re: separate antenna mast from base
I never did - but as far as I know, it can (should be able to) be done by unscrewing it at the base...... -
Re: separate antenna mast from base
Hi Oliver,
yup, that's the easy part. Once the mast nut and the base nut are removed I took out the whole assembly but the (toothed) point where the mast and base meet is seized. I have a replacement mast that is OEM style but I want to avoid further damage to the base and reuse it until the vendor has an OEM base that's coming in the summer.
To be more precise, I should have asked, once the nuts are removed and the assembly is out of the car how do you separate a seized antenna mast from it's base with minimal damage.
Thanks.
Michael B.Comment
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Re: separate antenna mast from base
I don't know that the antenna used later is exactly the same as the fixed length antenna I'm familiar with, but I think Oliver is actually talking about unscrewing the mast from the base. The base mounting nut is another deal altogether.
On earlier antennas, there is a slightly enlarged, tapered portion of the mast just above the base with flats machined on it (should be obvious on your replacement mast). If your antenna has the flats, then the mast was assembled to the base by screwing it on. Otherwise, if no flats, then it was swaged on and is not replaceable. Don't expect it to be easy to get it off...they torqued it on there to stay.
You'll have to come up with an ingenious way to clamp the base in a vise without damaging it, i.e. doubling nutting (?), wood blocks, thick rags to cushion, etc. Use an adjustable Crescent-type wrench in good condition (little wear) and adjust it to fit tight on the flats with zero clearance. Readjust the wrench for zero clearance after every turn.Comment
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Re: separate antenna mast from base
the base on the 77 is held in place by a nut above against a ground/re-enforcing plate below. The mast itself is held in place against the base by a smaller smaller nut once the base is set.
Where the mast mates to the base it is not screwed down as it mates against teeth that prevent it from rotating. But I had not noticed a taper, which would complete explain why this relatively clean part is not interested in departing from it's base.
I like the idea of the double nut because I had already tried everything else. If I manage to get them apart I'll publish the "fixture". In the past I've stuck things in the freezer to separate parts gently. Given it's -10 degrees now in Markham this is a moot point.
Thanks Chuck
Michael B.Comment
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Re: separate antenna mast from base
I was hoping I was remembering it correctly, but yes, I remember the teeth now. It was the mast retaining nut that had the flats. The taper I was referring to was the exterior of the mast base, not the fit. Try some WD40 on the teeth and let it soak...it may take a little persuasion. You probably have a little corrosion in the fit (cylindrical if I remember correctly)...it has to be a tight fit for electrical continuity.Comment
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Re: separate antenna mast from base
Can you post pictures, please?Comment
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Re: separate antenna mast from base
I can't find anything since I moved...If I could find my mast, I would take a picture for you. I'm not sure what you're interested in; if it's a close-up detail of the teeth, I think we're out of luck.
Below are some mast photos from a known vendor site. You can learn a lot about various Corvette parts from free catalogs and information on the internet. This one show the tapered mast base plus the retaining nut. The straight cylinder contact area is longer than I remembered, and fits in a deep well in the antenna base...the mast nut secures the mast in place:
https://www.paragoncorvette.com/p-35...enna-mast.aspx
(click on View larger image)
https://www.paragoncorvette.com/c-23...FilterID=23375&
(this should show all their antenna parts with a schematic of the entire assembly...if this doesn't show the schematic go down to 69-77 antenna mast, click, then click on the schematic at the bottom of the page.)Comment
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Re: separate antenna mast from base
The first shot is of the new mast (note the teeth).
The second is the original mast and base that I'm trying to separate.
Double nut won't work by the way, which becomes obvious when you look at fact that both nuts/retainers screw on the base and the mast is compressed down into place by the top cap.
I'm trying a couple other ideas.Comment
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Re: separate antenna mast from base
I have sawed notches in the base to save the original mast. A new cable and base is pretty correct. Sometimes they act like they are welded together. I doubt their is any way to save the base.Lyle
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Re: separate antenna mast from base
Pretty clear from your new base why the old mast is "welded" in place...the new base has no matching TEETH. That top ring of the new base is perfectly smooth.
I don't know how they did it (hydraulic press?), but it appears when the factory assembled the mast to the base, they forced the mast INTO the base to make the matching "teeth" seen on the top ring of the old base. I doubt the retaining nut threads have enough strength to pull that mast far enough down in the base to deform teeth into the top ring.
Since your old base is sacrificial, Lyle has the right idea...slot the base, probably every 90 deg, using a cutting disc in a Dremel tool. Try not to get into the mast, but if you do, you'll have to smooth any burrs off the fit BEFORE you install it in your new base. The fit is probably tight enough that burrs will score your new base.
I would try slotting the old base down maybe 1/2" in four places, then try working the old mast back and forth using pliers on an area where damage won't show, and/or interfere with the retaining nut. The longer the plier handles the better for gripping. You can use a file to dress any scarring to insure everything fits back together if you get some marking.
At first, just short intense efforts clockwise then counterclockwise, until you know the mast has actually moved relative to the base. Don't continue to turn the pliers if they begin to slip on the mast. If nothing is happening, extend the slots further. Once the mast actually moves, the battle has been won...you just have to keep working it while pulling lengthwise.
Sorry about the double-nutting idea...after I thought about it, I realized it was totally dumb.
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Re: separate antenna mast from base
the new base is a mistake on the part of the vendor - something they are working to correct as we speak. They were in the midst of designing a "perfect" mast which included a correct ball size and teeth to match the original base.
The mistake was that they shipped the new style mast with their previous style base and are currently retooling for the toothed style, hence the mismatch in the photo. Good eye.
If you have a really good eye you'll notice something else in the photos. They got the teeth backwards. They cut the profile for the base on the mast. A couple days ago I sent them the photo to see where they go. They've been pretty good at correcting mistakes.
As to the original assembly, it's now in the freezer. Let's see who's going to win this battle. So far it's antenna 1, me 0.
Cheers.Comment
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Re: separate antenna mast from base
yes the cold will shrink both, then you hit the base with a blow dryer in the hopes it will expand sooner and faster than the mast but I think I know who will win this round as well ...
I've done this before with seized suspension components but at least there I could press them out.
.... (commmmooon' freezer ...)Comment
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