The factory glued it; so can you. Also, an auto glass shop might have access to urethane glues that your local Ace won't be able to sell to random folks on the street... if you're desperate, you can always give them the job.

I've had mine on for several years, and I glued 'em myself. Al is right: cleanliness is absolutely essential. First you get it really, really super clean, and then you clean it. Then you clean it again. Follow it up with a good cleaning.

The latch itself just needs to be brought down to clean, bare metal. This process is well-understood and is pretty similar to the process for the glass.

My cleaning process is pretty similar to Al's, which might be why we've both had good "luck." My process: Remove the window from the car, use a razor blade to remove old glue, wash the whole window in soap/water, dry it, then use acetone to thoroughly degrease, then alcohol to remove the acetone residue. Then measure the correct location of the latch (don't guess! Putting it too close to the frame will over-stress the bond) and mark the *outside* of the window (duh) so you know where to glue your latch on. One last pass with Windex/ammonia where the latch is going, using a fresh paper towel of course. Because you don't want so much as a fingerprint on that glass. Basically, if there is *anything* on the glass it will greatly weaken the bond. So get stupid with the cleaning supplies.

I'm with Klaus: a good epoxy that claims high strength on both metal and glass, will do it. The stuff that worked for me is Devcon "2-Ton" brand epoxy. Ace carries it. Don't use just any epoxy, choose a good strong slow-acting two parter that specifically mentions on the packaging that it sticks to glass. Glass isn't easy to adhere to, and only a few things do it.

Krazy glue is a total bust. Don't bother.

I've had bad luck with rearview mirror adhesives, but that was before I got religion on the cleaning process. It might well work. Get back to us if it does.

I did not make any attempt to rough up the glass. Just cleaned.

It can't be said enough: the procedure is as important as the glue is. One of my rear wing windows ('70 145) is held with JB Weld, which, ahem, shouldn't have worked. Somehow, it still holds. Luck? It's all about cleaning, really. The cleaning was proper, so the bond is pretty good. That said, 2-Ton is the epoxy of choice for me.

I did the above-mentioned cleaning process, mixed a clean new batch of fresh epoxy per the instructions, set it properly (holding it in place requires some creativity) -- that's why you had to remove it from the car, this MUST be done on the bench -- and I use a light bulb to keep it warm if it's not a real warm night. Set it 24 hours, and if you did your cleaning it'll hold. Maybe not forever, but for long enough that you'll hardly remember the last time you did one. This process is just a part of the regular care and feeding of your 140. I've gotten it up to about 2-3 years between failures.

If you can't handle the overnight-on-the-bench thing, then try the rearview mirror adhesive which is much quicker to bond.
Keep us posted!