A body back glass drain holes
 

I'm a long time classic car guy (mostly '55-57 Chevys) but now I'm venturing into the realm of 1968-72 LeMans/Tempest/GTO. I have a question for those of you experienced with this generation of A body cars.

Do the 1968-72 LeMans bodies have any sort of drain to remove the water that collects around the back glass between the bright trim and body shell? Or does it just sit there until it evaporates? My initial research suggests the latter, but I want to confirm this is the case.

The same question applies to the windshield.

On '55-57 Chevys (what I'm most familiar with), both the windshield and back glass have rubber drain tubes that mount in the bottom corners of the glass opening and drain into the fender wells. These drains sit below the rubber seal that holds the glass to the pinchweld, and they work fairly well unless they get clogged with debris.

From what I've been able to gather thus far, the 1968-72 windshield and back glass are glued in like more modern cars, and do not have a similar provision for draining away water that collects.

Also, as I search for the "right" car, are rust holes in the glass cavity visible from inside the trunk? (I have a borescope, so that may help.)

None of the A bodies had drain holes. All A bodies used a sealant call Thiokol to seal the front and rear glass. Urethane is the modern replacement.

https://drive.google.com/file/d/1rpd...b5U15Jszu/view

Don't believe that answers the actual question by the OP.

Some cars did have a drain hole in the lower corners with a drain tube that ran into the trunk drop-off, and drained out the groove of the body panel plug hole.

But no 64-72 GM car that I know of used that 'feature'.

I believe it was abandoned due to the fact the drain hole/area would build up with debris too easily. But this is just a 'theory'.



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The 68-72 A cars (all divisions) used a "trunk filler' panel between the trunk lid and the rear window. There was no provision for water to drain away from that rear lower channel. A vinyl top compounded the problem, one of the reasons personally sought out a NON vinyl car for myself. That, and the memory of New England cars, and the bubbling rust that was almost always under vinyl tops of 12 to 15 year old cars in the early eighties when was a kid.
The windshield could drain at the bottom, into the cowl cavity. This was a change from the first gen A cars, where there was no provision for that, like the rear window. In retrospect, wonder why the designers didn't have the front edge of the trunk lid, meet the rear window bottom, like the '68-'72 X cars did. That would have solved the rear window drainage problem.
They could have also had ALL divisions use the same rear window, and roof structure, giving considerable cost savings over the five year generation. Believe only the Skylark and Chevelle shared roofs, and side glass in all four places. Their rear windows differed, however.
Of course, nobody then thought these cars would become icons, and kept and restored fifty plus years later. Vehicles were even more disposable then, and crashed more often then, by a generally younger market.

Thank you - that confirms what I'd thought. This explains why rust in the bottom corners of the back glass is problematic, and it's something I need to check closely when inspecting prospective purchases.

So, what about the '68-72 LeMans convertibles? Other than the obvious problem with old tops that leak, do convertibles have similar issues with draining water away from this area?

One convertible I looked at had pictures inside the trunk that looked like it had rust in the same places where the corners of the back glass would be on a hardtop. Hence my question.

Even the big cars had their problems. My 61 bubble top was showing rust at the bottom corners of the rear class. When I washed it rusty water would run out of those corners while I was drying the car. Fortunate;y it was not running into the trunk (yet). I pulled the glass and sand blasted repainted the outer channel.

And I found that the factory expected the rubber seal to leak some into the package tray area. To keep the water from being noticed there was a gutter under the glass on the inside that drained down just in front of the rear wheel. All steel gutter no rubber tube. I suppose that was why the rocker in front of the wheel rusted.

Well, I think in front of the wheel well rot was from debris gathering in the rocker panel which migrated from the cowl vents or other areas. But could be wrong on the '61.

Window channels are there for the trim, which was a secondary 'safety' item to help prevent glass from blowing out at speed or in accidents. So there was a reason for them, by design.

Newer cars use an adhesive-sealant, and other methods to 'properly' retain the glass.

Anyway, the gutter, if kept clean and somewhat dry, wouldn't be as much of a problem, but debris is the primary cause of rot there.



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Convertibles have a gutter to channel the water into the rocker area in front of the rear wheels. At least the 64-67 did, I assume the 68-72 were the same

Eventually they create their own drain holes - they rust through letting water into the trunk.

A design flaw I guess.

None of these cars were originally intended to last as long as the ones we own now. :)

I need to locate all of the drains and make sure they are clear. I know about the ones in the bottom of the doors. From this thread it sounds like there should be a drain in front of the rear wheel somewhere. Is there some diagram showing where all of them are?


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I added drain tubes in the rear corners of the rear window area of my '67 A body. Drill a hole, epoxy them in, drain out thru the trunk area. I used brake tubing with flared end at the top.

George

Same design as the 64-67 like I surmised

I *knew* someone with a 67 had done it, thought it was Old Goat 67.

Ive seen some pretty creative ways to fix the rear window/standing water issue.
Many years ago,a friend bought his sons first car,a 68 LeMans,that the creative seller
had mudded in the channel and with bondo still fresh,pushed in the trim,using bondo
to fill the gap and glue the trim in place.
On finished cars,I fill the channel full of 3M window sealer,wipe the excess that oozes out
and have the guy who replaces the glass cuss me. Leaves and dirt with moisture added
guarantees rust.
My 65 GTO had a leaking windshield at only 4 yrs old.Make sure you blow the front and rear
channels dry,with leaf blower or carefully with compressed air.