Center windsheild post

What is the purpose of the center post, besides hang the rear view mirror on? The reason I ask, is because I'm finishing the install of the windsheild on my car and when I draw the post down tight to the body there is a huge gap in the center of the windsheild between the body and rubber. When I push on the center of the windsheild to tip it forward it closes the gap up some. Now, I have not installed the front trim piece yet because I want to make sure that the windsheild is correct before I button it down. Even with the trim piece installed up front the still has a nice size gap.

This is a Beck windsheild installed on a CMC. Has anyone had this problem? Thanks..

I did, The pole is more for the mirror, but does help keep the center of the frame down.

I had to play with the aluminum molding under the rubber. I moved it in about an inch. This forces the rubber to shift up a bit.

The center post is what keeps vertical pressure on the windshield assembly w/o it the windshield would have little support and rock backwards.
What I do is use a narrow bead of GM windshield adhesive under the windshield base rubber to keep it secure to the cowl aluminum trim.
Be careful not to over do it and have this stuff come out from under the trim and onto the paint and or dash vinyl...it will stay on your hands for days too.
Lightly snug is all you want to go with both the posts and center post. ~Alan

Napa's Klean Easy # 6383.. Is the best cleaner to have handy for urethane clean up ,its safe for most paints. You better have a quart handy. It's also a good bug and tar remover. Very Very Handy

Just got done doing the same thing, although my windshield is a CMC mounted to a CMC body....I removed it to install the dash trim and just put it back late yesterday.

Look up the CMC/Fiberfab assembly instructions in the "Library" section on this site - not a lot there, but better than nothing.

Once you have the bottom rubber gasket mounted on the glass, then it should line up (more-or-less) with the metal trim piece mounted to the cowl. If you've not yet mounted the metal trim piece, then the CMC assembly instructions tell you how, but I would mount the top frame on the windshield and slide everything into the side mounting posts and THEN scribe the line where the metal trim should fit. Make sure that the windshield is sitting "flat", meaning that it doesn't rock forward to back and simply sits there without the center prop (although you will get a small amount of rocking, maybe an inch at the top).

Now for the bottom gasket. I have a CMC version, and it has a lip on the front that purportedly slips over the lip of the metal trim piece mounted to the cowl. The angle for that lip is totally wrong, at least on mine, so we just pushed the gasket up against the metal piece from behind, and glued it in place with black silicon caulk. Alan's stuff probably works better, but will be harder to get the windshield out if you ever need to, and the silicon stuff has lasted now for 5+ years (it's pretty tough).

As for the Center rod, it should be just about finger tight, no more. DO NOT CRANK THE CENTER ROD DOWN TIGHT!! In fact, the entire windshield should just about float in the frame with very little tension on it, otherwise it will surely crack. It is designed to sit at the proper angle when it is installed on the car, and will do so without the prop rod, BUT it needs the rod for additional center strength. I got the rod nicely finger tight, then one more turn with a wrench - that's it.

Hold everything securely by using silicon caulk (the black, driveway-sealing type) and seal up any pesky gaps around the rubber with it, too (be neat, or it'll make the gasket material shiny).

Good luck. gn

Oh, yeah.....and there will be a considerable (3/8" - 1/2") vertical gap at the front, bottom of the windshield when it is assembled to the car - As you've already found, that can vary by pushing on the top of the glass forward to tilt it slightly up, but it won't sit there, it'll rock back to where it was, maintaining that gap. Mostly, the gap is covered by the metal trim piece, and the lower rubber gasket can be pulled down slightly, if needed. That gap occurs because the glass is probably made to the specs for the original (steel) 356, whereas the cowl shape of most of the replicas doesn't accurately replicate the curve shape (same thing for the rear cow behind the rear seat, but that's for another post).

That's why we put the lower gasket behind the metal trim piece (along with the mis-match problem of the angles for the gasket lip) which allows a little room to fiddle with the gasket on the glass to push it down 1/4" (or less) to make it all look "right" across the metal trim piece. You could also put a piece of small vacuum hose in the corner under the lower gasket and against the metal trim to provide a spacer. I didn't, but we talked about doing that. At that point, most of the weight of the windshield is sitting on the lower outside "wing" corners and the rear edge of the lower gasket, anyway.

As you install and tighten the center prop rod, it should pull down on the frame and very slightly forward, but not very much of each, as you're only getting it only slightly more than finger tight, right? Once the rod is installed and everything is caulked with Silicon or something, you'll be surprised at how everything firms up.

gn

I had the same problem with my CMC . I bought a new bottom rubber seal from JPS. It's a bit thicker than the CMC piece. The correct way to deal with this problem would be building up the mounting area . That's if you are going to paint the body. Another tip regarding the center post. Do not allow any of the post metal to contact the glass. It will crack the glass with the slightest contact pressure. You may need to grind it down a bit to prevent it from ocurring. I had a very expensive learning experience with mounting the windshields.