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1981 t-top adjustment

Old 05-01-2011, 11:52 PM
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sabre1981
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Default 1981 t-top adjustment

I have the understanding that they can be adjusted. If so, how do you do this? They both have a small leak in or about the center of each, however the weather stripping APPEARS fine. There is slight bowing in the center of them, so I am thinking this is the problem. I don't want to replace the weather stripping if its not the cause of the problem. Thanks for any advice.
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Old 05-02-2011, 10:02 AM
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damoroso
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First question is are the tops glass or fiberglass? The glass tops don't fit as well as the fiberglass tops do and they can be cracked if you don't do the adjustment properly. The procedure is in the service manual and if you don't have one, you might consider getting one, they're really handy!!

Basically there are two adjustments, there is a side to side adjustment and a height adjustment. These are made by the lock tabs, the switch plate, and the locking rod. First, pull the lock tab trim pieces, and the retaining latch trim piece. Then loosen the lock tab and latch retaining nuts. Loosen the switch plate screws (don't remove these, you'll be sorry).

The lock tabs help control the side to side and height of the top, the switch plate controls the outside height of the top. The latch controls the "clamping" of the top.

Position the top with 1/16 to 1/8 inch along the halo panel (get this even along the back length of the top), max 1/2 inch between the tops along the middle of the top of the car, and a minimum of 1/16 inch between the top and the windshield trim. These are the specs for where the top should sit.

The lock tabs use shims as necessary (you can get these from any supplier) to adjust the height of the tops. I'd start with what's ever in the car now, and go from there. You might have to try a few times with the shims to get the top where you want it. Once everything is where you want it, tighten the lock tab nuts and the lock switch plate.

You should see a scribed line on the extenstion pin of the latch rod. Once everything is adjusted, make sure the rod goes into the switch plate to the scribe line. If not, use a screwdrive in the slotted end to adjust as necessary. The adjustment on the latch lever is for a 13-16lb pull to release.

If you're looking for a leak, try using baby powder on the sealing surfaces of the tops. Then use a garden hose and wet the tops down. then, carefully remove the tops and look for the tell tail water marks in the poweder.

I hope this isn't to confusing and helps!!
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Old 05-02-2011, 10:19 AM
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Red 69
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damoroso, you seem to have some experience with t-tops and I have a similar problem as sabre. It seems my fiberglass tops are warped, or something. They fit fine, but look raised in the center of each top, and leak badly. They are adjusted as far as they go down at the latch and the seals are soft and pliable. Do these fiberglass tops warp?

BTW...my glass tops don't fit well and leak as well. I have had the s/s t-bar and windshield out and re-fitted. There was no rust issue in the windshield or t-bar area and all given a coat of epoxy paint. The windshield was not properly installed when a PO owner the car, so it was re-done. My question is primarily regarding the possibility of warping of the fiberglass top as a problem. Have you heard of anyone having a warping problem?
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Old 05-02-2011, 11:59 AM
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Red, I've not known of the fiberglass tops warping. The fiberglass sits on a steel frame so that would make warping difficult. That doesn't mean it isn't possible, I just don't think it's likely.

A couple of things I would try. First, go through the alignment and adjustments I laid out in the above post. Start from scratch, just because the latch is really tight, doesn't mean it's adjusted correctly. If the latch is really tight, and the shims aren't correct, I can see how this might pull the tops up in the middle. Once they're adjusted, you might try to determine where the leaks are specifically, it might help you figure out if it's the tops or something else. Take a good look at the seals, make sure they don't have any tears or gouges out of them too.

You also might be able to find someone who would be willing to try their tops on your car and vise versa. That would help determine if your tops are actually warpped.

I'll tell you this much, I have glass tops on my car, and they don't leak. The passenger side did leak litterally a few drops on a trip back to Jax from Coco Beach but that was during some very, very hard rain (hard enough traffic was stopping on the highway). I found I had to adjust my up stop on the passenger window just a touch. Zero leaks now.

Hope this gives you some ideas and places to look!
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Old 05-02-2011, 09:42 PM
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Red 69
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Thanks for you suggestions, when I get a chance I will try tops from another car for comparison. They fit fine everywhere except the front.
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Old 05-03-2011, 12:11 AM
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sabre1981
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Thanks. They are fiberglass tops. It made SOME sense, lol. I'll look into it more on my days off.
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Old 05-03-2011, 04:03 PM
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http://willcoxcorvette.com/instructi...ment_77-82.pdf

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Old 05-06-2014, 10:52 PM
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Brandons72vette
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Would this help fix spacing issues such as this?

My '72 was recently wrecked, and is now being restored and hopefully it will turn out to be better than it was. The fiberglass is fixed, all of the body issues pretty much are fixed and it has a nice paint job. The only major concern left is adjusting the T-tops. I was told that it was just a matter of adjusting the tops to achieve parallel and proportionate spacing. Since I haven't done this before, and I know little about t top adjusting I am hoping to gather more information.

It starts wide at the drivers side slowly narrows to the passenger side. During the impact, it moved a lot of things like the doors and everything. It turns out it just had loosened and the door alignment was off. The shop fixed that, but didn't re align the tops. I told them to to, but they didn't. So I am curious if I can adjust them or if I am stuck with un uniform spacing.














Right now the car is disassembled as it was just painted, so most of the top parts are off of the car/tops. Since it was fixed, the gaps do look tighter, but they are still way too uneven for me to be happy. I know that with weathers tipping,trims, and all of the latches and everything it will be better but even still I am not sure it is adjustable.

Also, is the link from Wilcox the same for a '72? It says it is for later C3s...

Any thoughts?


The first pic of the car after being painted does not show how bad the alignment looks, in person it stands out more than it shows in the picture. The others are before getting fixed.

Last edited by Brandons72vette; 05-06-2014 at 10:57 PM.
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Old 05-05-2021, 03:09 PM
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Annies81Vette
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Yep, I'm sorry....I removed the screws and heard a thump. Probably the plate. How do you reinstall new t-top lock plate?
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Old 05-06-2021, 04:54 PM
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Originally Posted by Annies81Vette
Yep, I'm sorry....I removed the screws and heard a thump. Probably the plate. How do you reinstall new t-top lock plate?
Good question for a new thread.
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