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1985 Targa Top flew off

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Old Aug 15, 2018 | 07:57 PM
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Default 1985 Targa Top flew off

when I bought my 1985 Vette, it came with a glass top and a solid targa top. The targa top was missing one of the rear bolts, but I put it on anyway, thinking that three bolts would hold it. A few minutes later, I joined the flying roof club.

fast forward to today, I have gotten the top repainted and it's looking great. It's still missing one of those bolts on the rear. I've bought a replacement on eBay, but I want to ask-is it as easy as just putting the bolt in? Any tricks? Would a missing bolt on the rear cause the whole roof to fly off? The LAST thing I want is the newly painted top to go flying again, so if there's anything else I should check let me know.

The glass top has been in regular use for almost a year at this point and not had any issues, so whatever else might be wrong would be with that top and not with the car itself.

Thanks!
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Old Aug 16, 2018 | 09:18 AM
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Nearly 100 views and no replies? wow. I didn't expect this to get that much attention.

After thinking about it, I think I'll check at least that the threads aren't stripped from when it flew off.
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Old Aug 16, 2018 | 09:21 AM
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I don't see how one bolt could cause the whole thing to fly off unless it separated from the frame?

And that I have seen, actually. I just bought one from the local junkyard that is coming loose there.

Did they glue it back and if so, with what? I believe that is supposed to be panel bonding adhesive. I know the forces on it are pretty strong with the windows down.
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Old Aug 16, 2018 | 09:30 AM
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Originally Posted by confab
I don't see how one bolt could cause the whole thing to fly off unless it separated from the frame?

And that I have seen, actually. I just bought one from the local junkyard that is coming loose there.

Did they glue it back and if so, with what? I believe that is supposed to be panel bonding adhesive. I know the forces on it are pretty strong with the windows down.
I had the windows up-I think? It's been nearly a year ago since it happened.

I agree that one bolt doesn't seem like it should cause that, which is why I want to be very careful. After spending the money to get it repainted, I want to make sure that I know what happened and that it doesn't happen again.

The roof appears to be ok and in one piece, no missing hardware, just missing the passenger rear bolt.
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Old Aug 16, 2018 | 09:36 AM
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It's odd.. I know the one downstairs (came off an 84, I think?) appears to consist of two major parts.

1) A "frame" which all the attaching hardware goes through. It kinda resembles the "targa truss" some of the guys here have, actually.

I do not see how you could lose that with a single bolt, because it has one at each corner and bolts in quite securely.

2) A roof panel that is bonded to it.. Now that I can totally see losing if the bonding fails. In fact, that's what happened to back of the one I bought. You can literally lift it up about 1/4" off the frame at the rear. One spirited drive without a repair and it is gone!

So, I think you're probably fine if you put all the hardware back in it properly. At that point a failure would be whatever the repair shop used to bond it back together.

I can get pics of it if you want.
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Old Aug 16, 2018 | 09:59 AM
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Originally Posted by confab
It's odd.. I know the one downstairs (came off an 84, I think?) appears to consist of two major parts.

1) A "frame" which all the attaching hardware goes through. It kinda resembles the "targa truss" some of the guys here have, actually.

I do not see how you could lose that with a single bolt, because it has one at each corner and bolts in quite securely.

2) A roof panel that is bonded to it.. Now that I can totally see losing if the bonding fails. In fact, that's what happened to back of the one I bought. You can literally lift it up about 1/4" off the frame at the rear. One spirited drive without a repair and it is gone!

So, I think you're probably fine if you put all the hardware back in it properly. At that point a failure would be whatever the repair shop used to bond it back together.

I can get pics of it if you want.
I'd greatly appreciate pics if you don't mind, thank you.

I guess I assumed that having that one bolt off was enough to allow it to work itself loose from the others.

It was about 15 minutes of driving at 70mph, so it's not like it was a lazy drive around town. Happened just after I finished my test drive and bought the car, of course. Thinking about it, I'm pretty sure the windows were down because it was hot and the A/C didn't work at the time.
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Old Aug 16, 2018 | 10:20 AM
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The early Cars had a Integrated Mounting with a Cone (Built into the Roof) unlike the later ones with a replaceable Mount. Before going anywhere I would check Those Front Mount threads in the Roof. One missing Bolt in the Rear of a properly Snugged roof, I don't see causing the Roof to fly, Noisy Yes, Not Recommended Defiantly. There used to be a Rebuild Kit that you would Cut the Mount out of Panel and replace the Inners (PITA and Ugly) If Striped Heli-Coil if there is enough to Grab.

Last edited by s carter; Aug 16, 2018 at 10:48 AM.
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Old Aug 16, 2018 | 10:26 AM
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I also find it odd that it would come off with only one bolt missing and a rear at that. Here are some pics of a truss bar same mounts but 91. My guess is it was not secured properly.



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Old Aug 16, 2018 | 10:47 AM
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The screwdriver passes through the separation between the frame and the roof panel.. You can see where the attaching hardware goes.

So, IOW, if you weren't left with this frame bolted in the car after the roof flew off? The hardware was either loose or worked loose.

Because there's really no other way to lose it..

I would reinstall it and periodically check the hardware to make sure it's snug. A torx screwdriver in the console is a quick way to do this.



Delaminated C4 roof panel

Last edited by confab; Aug 16, 2018 at 10:50 AM.
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Old Aug 16, 2018 | 11:02 AM
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Thanks guys-yeah I thought I got it snugged down pretty well, but maybe I missed something? I will definitely check it out, and the roof definitely came off as a complete unit, nothing came apart. I don't have the roof currently (still at the paint shop) but now I'm wishing I would have tested it before paying to have it refinished.
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Old Aug 16, 2018 | 11:32 AM
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I dont see how missing a rear bolt would make it come off, rattle like hell, yes, but not come off. I know I've driven with one loose before.
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Old Aug 16, 2018 | 11:36 AM
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Originally Posted by Bfenty
when I bought my 1985 Vette, it came with a glass top and a solid targa top. The targa top was missing one of the rear bolts, but I put it on anyway, thinking that three bolts would hold it. A few minutes later, I joined the flying roof club.

fast forward to today, I have gotten the top repainted and it's looking great. It's still missing one of those bolts on the rear. I've bought a replacement on eBay, but I want to ask-is it as easy as just putting the bolt in? Any tricks? Would a missing bolt on the rear cause the whole roof to fly off? The LAST thing I want is the newly painted top to go flying again, so if there's anything else I should check let me know.

The glass top has been in regular use for almost a year at this point and not had any issues, so whatever else might be wrong would be with that top and not with the car itself.

Thanks!
You said it did
You can't lose your top even with only the fronts tight
Not likely you had any bolts tightened

Last edited by Cruisinfanatic; Aug 16, 2018 at 11:41 AM.
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Old Aug 16, 2018 | 11:39 AM
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Originally Posted by Cruisinfanatic
You said it did
I don't see how you can lose your top with the front bolts fastened
That's my thought and why I'm concerned.
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Old Aug 16, 2018 | 06:40 PM
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It should be pretty easy to add the hardware, I had to move hardware from one top to another about 25 years ago I don't remember any issues.
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Old Aug 16, 2018 | 08:36 PM
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Happened just after I finished my test drive and bought the car
Seller left it loose.. Probably forgot.

(Which is easy to do)

Probably took it out for pics.

Last edited by confab; Aug 16, 2018 at 08:37 PM.
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Old Aug 16, 2018 | 08:42 PM
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Bolt it back in and go. I bet you're fine.
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Old Aug 16, 2018 | 09:11 PM
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is there a torque spec for the bolts?
I know the tool they provide just gets them tight based on what you feel is tight.

Just thinking, if the threads are partially stripped they might slip before reaching proper torque.
So that might be a test for condition of the threads.

Last edited by belairbrian; Aug 16, 2018 at 09:12 PM.
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Old Aug 16, 2018 | 09:16 PM
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6x1.0 is about 100-140 inch pounds..

It should hold that. If it doesn't it is probably not safe.
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Old Aug 17, 2018 | 12:22 AM
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Originally Posted by confab
Seller left it loose.. Probably forgot.

(Which is easy to do)

Probably took it out for pics.
I put it on myself. There’s a chance I didn’t torque it down enough but I’m usually careful about such things.
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Old Aug 22, 2018 | 12:15 AM
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Well I got the top back from the paint shop. Looks great, and it doesn't seem to be having any issues staying on. I tightened it down nice and tight, and the shop owner and I pulled on it and it feels pretty darned solid. I still have no idea why it flew off in the first place, but hey, it seems to be in good shape now. Thanks for all the help!

Now I just need to fix the cloth on the underside, it's sagging a bit. Any suggestions there?

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