I need to go to the people who know on this one. Just bought new weatherstripping kit from Keen at Carlisle. The pillar has the hinge or extension supposedly applied to all 1968-72. Dobbins states that the 1972 did NOT have the extension and the post did not even have this "hinge" on late 1971's. Keen is confused as am I. Can anyone help me on this. As well as I can figure I bought the car 16 years ago from the original owner and there is NO hinge! Thanks!!
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Re: pillar Post Weatherstripping on 1972 T-Top
Michael, it sounds like the car is telling you the truth. If the original owner did not replace the part in question (and it sounds like he/she did not) then you have the answer. That's the great part about original cars...they never lie!!!
regards Bill -
Re: pillar Post Weatherstripping on 1972 T-Top
Michael-----
Very interesting situation here. In fact, this is one of the great mysteries of Corvette parts lore----one of those strange anomolies of the GM parts system. Here's why: the original side pillar weatherstrips used for 1968 Corvettes, both coupe and convertible, were GM 3915875-lh and GM #3915876-rh. Very early in the 1968 model year, these parts changed to GM #3947943-lh and GM #3947944-rh. All of these pillar post weatherstrips have the lower "extension". The latter part numbers were also used in the very early 1969 model year.
In the early 1969 model year, the part numbers for the pillar post weatherstrips changed to GM #3966565-lh and GM #3966566. According to the parts manuals, the AIMs, and other references, these parts were used until the end of C3 production in 1982. Also, according to the AIM and other references, these parts had the lower "extension" for model years 1969, 1970, and 1971.
Now, this is where things get interesting. For 1972 and up, AND EVEN THOUGH THE SAME 3966565 AND 3966566 PART NUMBERS WERE USED, they DID NOT have the lower "extensions". Add to this the fact that if you bought either of these parts during at least during the last 15 years (they're still available for a GM list price of $127.50/each and I have them in the collection), THEY DON'T HAVE THE EXTENSIONS.
Consequently, I can concieve of only two possible things that could have happened: first, the GM #3947943 and GM #3947944 weatherstrips may have been ACTUALLY used during all of 1969, 1970, and 1971 production, EVEN THOUGH THE PARTS MANUALS, AIMs, AND OTHER REFERENCES DO NOT INDICATE THAT; or, second, the configuration of the GM #3966565 and GM #3966566 weatherstrips actually changed significantly for the 1972 model year and beyond.
EITHER of the above scenarios are VERY UNLIKELY ones in the GM parts world. But, as far as I can tell, one of them HAD TO HAVE OCCURRED.In Appreciation of John HinckleyComment
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Re: pillar Post Weatherstripping on 1972 T-Top
Joe,
Very interesting information.
On the '69, '70, '71 cars WITH the extensions, have you had a chance to draw conclusion as to whether these weatherstrips (with extensions) are molded in one piece, or is the extension a separate piece that is cemented to the main weatherstrip?
I seem to remember, that when I disassembled my original '70 coupe, the extensions actually came off as separate pieces, with a clean sharp separation line.
Chuck SangerhausenComment
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Re: pillar Post Weatherstripping on 1972 T-Top
Chuck-----
As far as I can tell, the weatherstrips were supplied as a ONE PIECE unit. They must have been originally molded seperately since the material of the extension and that of the pillar post weatherstrip are entirely different. Afterwards, they must have been bonded together in some way (which may be why yours showed a "clean" seperation when you removed the worn pieces).
However, they were never available as seperate pieces in SERVICE and there is no indication that seperate pieces were used in PRODUCTION.In Appreciation of John HinckleyComment
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Re: pillar Post Weatherstripping on 1972 T-Top
So far as we know from judging experience and revising the 1970-72 JG, the extension on the weatherstrip was not present in 1972. I cannot speak for late '71s. The longer piece was not available in repro for some time, and when it became so, it was much more expensive that the shorter one. Therefore, many people combined part of the original with the new and I have seen many cars with the two separate pieces. All original w/s that I have seen was one piece.Comment
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Re: pillar Post Weatherstripping on 1972 T-Top
Joe,
I think we could be onto something here. If we are, however,it will require revision of the judging manuals. I will have to dig out my old weatherstrips and extensions to see if the extension has a separate part number.
If the extensions were a separate piece bonded to the main weatherstrip by the supplier, then that could explain why the part number did not change when the extensions were added. GM did some strange things when assigning new part numbers, but I have to believe that a significant change like adding the extension would have called for a new part number. On the other hand, if a supplier was using an "approved method" to meet a "design change", i.e. bonding the extension to an existing weatherstrip, the extension probably would not carry a GM part number, and GM might permit the "production only" assembly to carry the original part number. Another thing to consider: Tooling for this type part is EXPENSIVE; Would a cost-conscious manufacturer retool if the extensions could be bonded to an existing part? Guess it would depend on the volume, which would be low for Corvettes, and the cost of labor.
Also makes sense why the extensions never made it into service. The customer would probably never notice a little corner-cutting ten years later. I know I am brain-storming here, but this is Very Interesting.
Chuck SangerhausenComment
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Re: pillar Post Weatherstripping on 1972 T-Top
Chuck-----
The two earlier sets of part numbers used on 68-early 69 had the extensions, for sure. The only real question is whether or not the last part numbers had significant changes made to their configuration beginning with the 1972 model year. Or, whether the last set of part numbers actually began to be used with the 1972 model year. In my mind there is no doubt whatsoever that the extensions were NEVER a seperate part available in SERVICE or used in PRODUCTION by GM. Even if they have a different part number embossed on them, it was never a SERVICE or PRODUCTION part number. At most, it was a COMPONENT of a PRODUCTION and SERVICE part. I really doubt, though, that you'll find any seperate number on the extensions.
Also, the extensions were never "added" to an existing part; if anything, they were SUBTRACTED from an existing partIn Appreciation of John HinckleyComment
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Re: pillar Post Weatherstripping on 1972 T-Top
Joe,
My misunderstanding. I thought that the extensions were not used in '68 and were added in '69 and later years to fix a water leak problem. I checked Dobbin's book, and the extensions are definitely on '68s.
Darn, and it was such a good theory too! I am still going to take a good close look at my original weatherstrips; when in doubt, put it back like you found it. Thanks for the info.
Chuck SangerhausenComment
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Re: pillar Post Weatherstripping on 1972 T-Top
This subject of whether the 1972 had the pillar post extensions and if in fact they were one or two pieces is interesting. Joe's response has been enlightening as have all that responded. I called around to our major parts catalogue people and so far not a one has a clue about this. The judging manual might need some tweaking on this one. I have decided to return the pieces with extensions and get those without and call it an experience. Now, when I go to Carlisle in August and I ask some first flight 1972 car owners to open their doors--what will I find? You bet, some will have em' with and some without. And those late production 1971's??? Thanks.Comment
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Re: pillar Post Weatherstripping on 1972 T-Top
Michael-----
If I found a 1972 with the extensions I'd probably suspect that they were incorrectly added. I really don't think that there is much doubt about the fact that 72s didn't have them. There are a whole lot of questions outstanding, but I dont believe that this is one of them.In Appreciation of John HinckleyComment
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Re: pillar Post Weatherstripping on 1972 T-Top
Joe,
Curiousity got the better of me; I had to go out and toss my garage to find those original pillar post weatherstrips and the extensions. I thought you might be interested in what I found.
Unfortunately, I could not find my weatherstrips, but I did find the left side extension together with the hardened elastomeric sealant that I dug from under the corners of the front fenders (parts catalogs show little triangular weatherstrips for this location, but not on my car).
My recollection was correct; the extension was, in my opinion, definitely molded as a separate piece. The end that mates with the pillar post weatherstrip appears to have been designed to overlap the weatherstrip; about 3/4" from the end, the thickness transitions from about 3/16" to about 3/32" uniformly across the width of the extension, ending in a squared off end. This thickness reduction occurs precisely where the lower mounting screw for the pillar post weatherstrip is located. The screw would, therefore, pass through both the extension and the end of the pillar post weatherstrip. The surfaces of the reduced thickness area and the squared-off end are smooth as you would expect from molding. If the extension was ever "bonded" to the weatherstrip, any adhesive or evidence of this is long gone. If the extension had been separated from the pillar post weatherstrip by tearing, you would expect the rubber surfaces to be rough and non-uniform. As I remember, there wasn't any tearing, the extension and the weatherstrip came off in two pieces.
I looked closely at the extension, but as you expected, found no part number. The only identifying mark was a "23", which probably represents a mold or cavity number.
My car is a very late '70, probably the last day of production.
Chuck SangerhausenComment
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Re: pillar Post Weatherstripping on 1972 T-Top
If you find flight cars with these extensions, the owners have not read their JG and should lose points for them. The 1970-72 manual says that '72s definately did not have them.Comment
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