Hello, I have to re-seal my rear window on the 68 Firebird. What do you reccomend, the 3M butyl tape type sealer on the roll, 3/8" or 5/16" width, and any other tips to be sure it seals? Thanks, Jeff

I always use 5/16" with silicone caulk. Been doing that for 30+ years. (take the window out and clean the channel first) I use a narrow strip of metal (banding material) to neatly scrape and fill the caulk into the gap around the butyl forming close to a 90 degree angle with the glass.

Others on this site seem to have a different approach tho...

this sort of windshield and back glass installation worked for years and for the sake of originallity you may wsh to stick with it. the only change I would make is to use a proper auto glass butyl sealant and a butyl compatible pinchweld primer with your 5/16 kit. with todays vehicles by law the windshield must keep the occupants within the vehicle during a crash and the windshield and back glass have become a more structural part of the vehicle. we use Sika products for all of our glass installations. worth reading anyway. sorry I tried to copy the link but am having trouble. search "SicaTack Drive" and check out the pdf download at the bottom if the installation instructions don't come up right away

I worked for a glass shop in the 70s. We always used 3/8" butyl strip. There are those that would argue urethane is the way to go now, but I still use butyl. One thing to be aware of, there's acid in silicone that's used to cure it. It shouldn't be applied directly to metal. Also, it won't seal to the buytl.

The 3/8" is too thick for fgf's. It will force the chrome mouldings out too far and cause all kinds of grief. Guess how I know....

one other thing worth mentioning, if you have to replace any retainers for the chrome do it with the window out. when you compare the new ones with the old ones (installed), you will notice that the old retainers fit more loosly where the chrome snaps in. you should use a screwdriver or a gasket scraper to bend the new ones away from the body a little or you will probably damage your mouldings or paint trying to force the mouldings back in

Thanks all for the info, I got the 5/16 3M butyl tape. I am thinking about trying to do this without the caulking. If it leaks, then put the caulking around, or should I just go ahead and caulk it? What do you think? Thanks!

I would never even consider it without caulking.

But that's just me.

ok, thanks, i will do it then!!