Just bought a 68 GS350 a few weeks ago. Thought I could see "water spots" on the windshield, so I cleaned it inside and out, but had no effect at all. Upon closer examination, it actually looks like it's bubbled "inside" the glass throughout the entire windshield. Is this an indication of a cheap replacement being put in at some time? Or is it just that it might be showing its age? I have no idea when it might have been replaced. I'll track down some identifying #'s on it and post them later.

Dave, as you probably have heard, the windshield on cars since the late 20s is made of laminated safety glass. The layer of plastic film in between the two glass layers may very well have a manufacturing defect since new causing the spotting.

While doing contractor work in an L-O-F auto glass plant a few years ago, I watched a worker set up the mold for a curved rear glass on an 88 Cadillac. He was setting up to make a run of replacements that had not been made in a while. He spent hours adjusting the oven mold to match the pattern. There was a tremendous amount of hand fitting to make the glass fit the opening on the car body. I can believe any shortcuts in manufacturing would give the spotting you see.

What you have is not optical distortion is it? This was common on cars with sharply bent curved glass. Would think yours is not curved that sharply though. Looking out through the windshield along the curved parts shows mild distortion similar to a fun house mirror. Even factory windshields did this when new. It was worst on the wraparound windshields of the late 50s.

After many decades, the plastic can separate from the glass and start to turn cloudy or milky from the edges inward. The white color appears to be caused by water getting down in between the layers. This can be seen on some early 50s cars or before which still have the original windshield.

If the glass has just separated from the plastic without getting wet down inside, the effect would be clear bubbles imbedded in the glass. Some early 60s TV sets of mine use this laminated glass. As the separation starts, good sized bubbles appear on the screen.

Would be great to see what brand that glass is on your 68.

[This message has been edited by TODD (edited 10-10-2001).]

Todd, I found the problem. Taking a much closer look at the glass, I could see the "bubbles" were not in between the glass sheets, they are on the surface. With a razor blade I could scrape the material off, but windex didn't remove it. I wonder if it isn't wax residue from someone running it through a car wash! Any idea what will remove something like that? By the way, some glass on the car is LOF, some is PPG. This is the same car that has a thread going under Decoding and Identification under "Matching Numbers" topic. I've been having trouble finding the engine prod code. Still can't see it between 5 & 7 plugs area. With engine in the car, it ain't easy. Looks like I have a 71 350-4 block with 72 heads, "72" is cast into both heads, but don't know if it was switched to 4bbl from 2V. Block # is 41H107551. Found an old magazine that confirms the 41 is Buick 1971, but doesn't match the car VIN. Just spent about 45 min on the floor trying to id my rear axle also. It is a posi but after wire brush and razor blade, I couldn't find the code on it. Should be passenger side on the front surface? Supposedly rear came from a 72 Skylark. I'll have to get it up in the air and do a better cleaning job. Also, the driver side frame by the gas tank is a spot for the VIN also, right? I found the following: 08663 S 122
1 29 N1 CJ
Those mean anything to you? Obviously not a VIN. I've rambled enough. -dg-

http://www.buicks.net/forum/smile.gif Well, I found my axle code this afternoon. It is LT, and it was on the bottom of the tube on the driver side. Since this car will only be driven around town, no "racing", the 2.56 ratio isn't really much of an issue. But I do have access to another 68 posi rear end that should have a higher ratio if I want to swap. Mine isn't original anyway, came from a 72 "lark. At least I would have another same year component. I'm scavenging a totalled 68 GS400 for usable parts this weekend. It's been sitting on the old farm site for 22 years. Outside and uncovered unfortunately, but should have plenty of goodies. The engine and tranny are long gone, however. Don't know if I could track it down or not...

Say, besides the LT on the axle, which could be from a number of different years, I found a casting # on top of the diff housing. It is 1385724. Can that be traced to a specific year, or is it pretty generic?

[This message has been edited by dg-gs350 (edited 10-11-2001).]

Don't use a razor blade on glass, ever! There is a fine powder, super fine that removes surface residue. I will post the name of this product as I must dig deep into my garage to find it but it is excellent for hard water spots and the like that dry to the surface of the windshield.

Thanks for the tip...I only used the blade on a small spot in the bottom corner to see if the "stain" was actually a surface material, as it appeared to be, and it was. Yes, please post the name of the product you referred to. -david g-

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David Gramlow
1968 GS350
GSCA 861

Hey, Dynamax...any luck finding the name of that cleaner you needed to dig through your garage to find?

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David Gramlow
1968 GS350
GSCA 861