My '84's acrylic top is what appears to me to be "crazed". I've never seen anyone else's but I've heard the term. When I look out from the inside in any kind of bright day, I see what appears to be all manner of tiny cracks.

My main question is - is this dangerous? Is this something that can just more or less disintegrate and fall into the car, or is it just an inconvenience that makes it hard to see out?

 

Eventually it's going to crack all the way through, and leak like a sieve.

My recommendation.... start searching long and hard for a fiberglass top.

Don't bother with another acrylic. Their frames are infamous for not fitting right no matter how you adjust them until it's sat bolted in for while... (and that runs the risk of cracking your brand new roof too!), they're more expensive than the fiberglass tops usually are. I wish I had never bought another acrylic top. I wound up finding a fiberglass top a few months later...which is now on the car. I doubt I'll ever put the acrylic back on, other than for car show purposes. Too fragile...too hot (you'd be amazed at the temp differences in the cabin clear vs fiberglass).

 

My top has been crazed like that for years. I don't believe it has anything to do with cracking. You can only see it from the inside. Age takes it's toll.

 

Top on my 87 has been like that since I got it in 98.

 

- my 85's top has been crazed since I purchased the car back in 96. cracking all the way thru and leaking is BS.

 

They do it. It's just a matter of time.
What do you think the craze lines are? Decoration?

It's the top starting to suffer from stress and delamination.

 

I've had several glass tops and all of them were "crazed". None of them cracked or leaked.

I had my '85 for 25 years with no leaks. I don't know how long the others were crazed, but no leaks on them either.

I can only see it from inside on a sunny day. From the outside I don't see it at all.

I wouldn't worry about it.

 

i guess you must be some frickin' polymer expert! I REPEAT -- my 85's top has been crazed since i purchased the car back in 96. the crazing hasn't caused any cracks, and it doesn't leak, so until it does,

 

Well. I guess I'll not worry about it too much, but watch for anything that might be indicative of a crack going all the way through.

Thanks all!

 

Well, obviously it isn't in the best shape as its showing signs of stress. But I think the other members' experience matters when they have real world examples of having crazing and it not leaking or notably worsening over more than a decades time.

The car I'm purchasing has a bit of the same on the acrylic top. I'll probably shop around for a fiberglass top myself. But i wouldn't exactly call your situation urgent. Just keep an eye on it. Maybe take some detailed photos as a reference to see if it gets worse.

 

Honestly, I'm not into the clear top - I'd be happy to find a new Torch Red one to replace it with. Or a pink one I can paint.

 

A pink one, lol. Was your car repainted? Torch Red started in '93, as the early C4 red was Bright Red. In fact, I believe '84 was a unique one, as they changed Bright Red a bit in '85.

http://www.corvetteactioncenter.com/...l#.Uq6HD7StaUs

You might be better off just getting a top of any color and painting it code 33 Bright Red (assuming your car still has the original paint color). They switched to code 81 in '85 all the way through '92. If you get a red top, it would need to come off of an '84 only if you didn't want to repaint it. Slim pickins.

 

My top has been crazed for years. I have wondered if it will explode into a million pieces some day.

I have both tops and use the acrylic one during the winter and the solid one during the rest of the year.

 

And yet, my car came with 2 different tops... one of which had already cracked through. And the other was just crazed when I got it.

Over course of owning it, the second which was crazed, did indeed split open, and begin to leak. It didn't even make it 2 years before it started leaking either. in the last 2 months, the cracking got so bad that you could count the number of new cracks every week, and come up with an ever bigger number. The last crack before the Acrylic top I bought came in, you could actually push with your finger, and widen it.

I didn't give the third top that opportunity. I bought a fiberglass top at the first chance I got. Funny I've not had a single problem out of that top.

Clearly I must have been hallucinating, and acrylic and lexan plastic never ever goes bad in direct sunlight and weather.
Maybe if you park your car in a garage, it won't rot.
Put one of those craze top equipped cars out in a southern summer then let it go through a couple winters. We'll see how long it lasts you then.

Here's a fun experiment for you if you don't want to risk your top.
Buy some lexan at lowes or home depot. Set it outside.
Observe what happens to it, as it ages. Particularly after it begins to craze. Notice how brittle it becomes? That's what your top does, as it ages. As the top flexes from various forces put to it from the car's structure, that brittle plastic? Is going to break eventually.

The roof is a structural member of the car. The lens, flexes at a different rate than the metal frame it's attached to. It also expands and contracts differently. Throw in uv and temperature damage and you get a cracked roof eventually.

Hell ALL plastic does it to some degree or another.

 

You hit the nail on the head of my disconsolance, Cliff.

I did read an article that seems to say it's cracks on the surface of the acrylic caused by stress and "solvent". So, they're surface cracks. BUT it does stand to reason that any crack has the potential of being .. a break.

 

Y'know, JD, I really don't know. The RPO says my car was "driftwood" when it was new. That means a repaint, to me. It doesn't appear to be "bright red" though, as I have a sample of that, and my car ain't it. I'm assuming "Torch red" as it's probably the default color, but we've certainly seen that "red", even the same name and color code, changes from year to year. I'm looking for a sample of Torch Red for comparison, probably from the late 80's.

I got a used gas door just because it was a good deal. I just received it the other day - it's apparently "dark red metallic" and I'm just slightly in love. Maybe I'll just repaint the whole car to match the gas door.

 

Is it possible that maybe the tops that have been reported as having actually split (as opposed to just crazing) might have been cheap non stock replacements installed by a PO at some time in the cars past? it's just a thought that occurred to me, that's all, I'm no expert at all. mine has been crazed since I've had the car, 3 years,doesn't leak and cant be seen from the outside so not a problem, at the moment, it will be replaced at some point in the future though.

 

Ah yeah. I'm not familiar with driftwood. Light bronze or dark bronze I'm assuming? Anyway, Torch red might be it then. Is it a bit more orange-hued than the bright red sample?

Well you certainly know I love DRM. If/when I get another C4, I'd like to contrast the blue with a red one (bright or dark). I guess we have a lot in common in that regard. As for painting yours, I'm a bit purist in that I'd want an '84 available color on an '84. But if you don't go that route, I don't think you can go wrong with DRM. I get googly eyed every time I see one.

Is that gas door the early DRM, code 74 from '86-'88?

 

clearly, you are quite knowledgeable on the pitfalls of "glass" tops on corvettes. I suggest you report your findings to GM. don't those idiots know they've been manufacturing a defective product for some 32 years now? after a quarter million faulty tops, you would think they would be smart enough to figure this out on their own. you should also post your expertise over on the C5, C6, and C7 forums, and save those owners from future disaster.

 

You always stretch my mind a bit, JD! I went back to the RPO again, it seems that 33U might have been Driftwood for Cadillac, but for 1984 Corvette it's bright red! That's great news, since it means the car is still the factory color and much easier to match.

Since the car is in decent shape to the back of the doors, I can now buy a kit to refinish the bright red just for the back end of the car. I'd always wondered about what a perfect job they'd done, since there's no sign of any other color.

Grrf. Now it all makes sense, paint color doesn't stay the same, even within GM. They use the same number for different colors from year to year. Nice to find out something that I'm sure every other person on here already knew .. sheesh.

I really don't have any idea what the year of the gas door is. I bought it used and it said it fit like 1984-1986 or the like. I'll probably pull the emblem off it and keep the rest in case of disaster.

BTW, here is a site that allows paint color lookup for pretty much any year and model of car. Foreign and domestic.

http://paintref.com/cgi-bin/colorcod...on=yko&rows=50