Rear glass install - where to apply sealant?

[buening 63]

I'm ready to install the rear glass in my mach and was curious if anyone has any tips on how to apply the bedding compound? I read the How-To that Mach1rider has on here, and he mentions putting a 3/8" bead inside the gasket pinchweld channel and then install the wire. Then he mentions putting sealer only in the corners between the body and rubber after the glass is installed. I'm not sure how this ends up being 2 full tubes. Should the entire area between the rubber and body (full perimeter) be pumped full of bedding compound after the glass is in place and the wire pulled, or is that just excessive mess-making?

[SA69mach 39]

There are three beads of compound that need to go on. There is a lot of controversy on when they go on, so bear with me.

The gasket goes onto the glass first. Some put a thick bead in the gasket and then slip it over the glass. Some only lay that bead after the glass is installed in the window.

There must be a thick bead of compound on the pinchweld, so it sits between the rubber gasket and the outer side of the pinchweld. Some folks lay it on the metal, and some lay it inside the groove of the gasket. I have done a window with a guy who insisted the compound go in the groove after the rope was set in the groove. That was messy. But it worked.

After the glass and gasket is seated in the opening, you lay a thick bead around the entire gasket, working the compound into all the gaps, especially the retaining clips. If you use a wet wooden ruler or wet wooden paint stirrer the compound can be pushed into the gap. Use a lot of compound and fill the gap in the channel all the way around the gasket.

 

for those who put the glass in dry, you have to lift up the rubber flap and using the nozzle, squeeze a full bead of compound between the outer glass and the outer gasket rubber. I think that is a good idea to do, even if you run a bead of compound when installing the gasket on the glass. You do not want to get a leak after all the work.

 

I always test for leaks before putting the chrome trim on now, since it is always a risk to take the trim off. it is easily damaged, and the trim clips come off sometimes when you pull of the trim. That makes a mess when you try to put them back on with compound all over the place.

 

There are some videos on you tube worth watching.

This pic is worth a thousand words too. shows where the sealer MUST be. (Thanks 22GT) There are various methods of getting it in there, but use a lot of compound and clean it up later.

[miketyler 15]

Good info - isn't the rear portion of the headliner tucked ion there as well on the 69-70? I was considering removing my headliner during my restoration but was warned that the back glass would have to be removed.

[buening 63]

Thanks for the info! Regarding sealant on the pinchweld, how can it possibly be applied to the metal when the "flap" of the gasket is the full width of the whole gasket? I would think if you applied sealant to the pinchweld and set the glass in place, the flap would sit on the sealant and then pulling the rope push it all into the interior (as well as a mess on the interior side of the flap). Thanks for the pic by the way.

 

Also, there is nothing wrong with my headliner but the overhang portion got pulled off when I removed the glass. Essentially there isn't any folding over onto the pinch weld. See any issues with that? I could always use a little urethane between the flap of the gasket and the portion of headliner to keep the headliner from separating. It is attached to the interior side of the pinchweld still.

[buening 63]

Any links to those YouTube video

Videos? I didn't find anything for the rear glass, only for the windshield which is a tad bit different

[SA69mach 39]

The headliner- if the headliner is damaged and needs to be replaced this is the best opportunity, although both front and rear windows need to be out to set the headliner.

If your headliner is in good shape, then take the opportunity to trim, set and re-glue.

 

The gasket does drag in some of the sealant bead as you pull the loop of wire/cord from the pinchweld lip - this is inevitable, and messy. That is why I also run a bead of sealant in the rubber before I put the wire/cord in place, and then another bead after. I figure it gives me three shots at leaving a good layer of compound on the metal pinchweld. Once the window is in place it is all patting and pushing to set it flush - there is no more opportunities to insert compound between the metal and the gasket.

 

AFTER that process, you squeeze a bead all around the window UNDER the rubber flap, between the glass and the rubber. It is a tight fit and you want the compound squeezing out as the flap lays down behind the nozzle.

 

AFTER that process you fill the channel between the body and the rubber, working it into the voids around the trim clips, and use a lot, fill it almost flush. Tamp it down. Do a water leak test. If dry, install your trim and water test again.

If leaking, keep tamping and filling. don't install trim on a leaking window. You may have to take it out and go again.

videos - take your pick - everyone has their own opinions about the 'best' way Here are two different ways. Last two are Mustangs to Fear part and part 2

 

[buening 63]

Thanks for the info. I had seen all three of those videos and are helpful, but are made for the windshield and not the rear glass....but maybe they are the same process. If you look at his first video at around the 3:45 where he is applying the sealant to the rubber seal, you will notice the flap isn't the full width of the seal like it is on the rear window seal. There is room for him to apply the sealant and not have the rope affect it.

 

Think I will follow your process of putting some in the rubber channel and risk the mess.

[GT350 16]

i done the rear on my 69 same as rich done the front one on a 67 mustangs to fear vid,i managed to get a leak free seal,a bit messy but keeps the rain out

[mustangstofear 608]

Just make sure you use a rope and not any wire, or you'll end up tearing the gasket. In my video you'll notice when i get in the corners I'm going in a clock wise direction with the rope to keep from tearing the gasket. Once the glass is in seal between the glass and with urethane ONLY, not the 3M bedding sealer. I wait until the next day to install the chrome to keep from pushing any of the urethane out.