sklearman

If I find replacement glass, I will probably go back to original OEM style as well, eliminating that variable. I am looking at a polycarbonate hatch which absolutely will not shatter. However, polycarbonate doesn't fare well in the elements and the company said I'd best go with normal glass. I suppose I could get some of that wax that they put on the canopies of fighter jets (which are polycarbonate) when the jets are not being flown.

One would think GM could have designed this right.

skinny z

Personally, I wouldn't go for the billet hinge but can understand why some would.
That said, are the GM mounting pads transferable to the aftermarket hinge?

sklearman

As far as I could tell (had to have a shop literally cut the through glass bolts off, 3 of 4 wouldn't loosen) there was no padding of any sort between the hinge plate and the glass. I am trying to find new OEM hinges but no luck. Everything out there seems to be the same billet hinge that you see on Hawks. I am definitely not coming up with any answers.

rurnt88

iTrader: (1)

I suspect GM designed these to deform to allow for variations in the shape of manufactured glass and body panels.

As a side note: In my opinion (2 cents), this malleability leads to other problems. Because they will deform, the pressure of gas struts has to be correctly matched to the hatch. Sadly, the struts for these cars are no longer available in the correct pressure(s).

Like so many others, the hatch hung off the back of the car. I have read this was an adhesion problem between the glass and hatch metal piece. Upon disassembly I found that the adhesion was just fine. The metal had not moved on the glass. But the hinges certainly did.
The hatch metal "reveal"(?) is located and held in place by the glass edge banding. The bands attach at the hinge bolts and are bolted to the metal panel. They are also glued to the side of the glass. I found that getting these aligned correctly is critical because they locate the position of the metal panel. I used a couple ratchet straps to get it aligned and marked before glue-up.

Hope yours goes together smoothly.

Oh, and I don't believe they make new factory hinges anymore. I plan to straightened mine and reused them.

sklearman

I may have to find a set on a salvage car. But I'm also thinking of using polycarbonate instead of glass. It will flex, not break. GM designed these hatches very poorly. They should have a wide piece of metal at the top, like the rear deck, that the glass glues into, but which would provide suitable material for the hinges to bolt to. I'm guessing it was for appearance reasons this never happened.

I did see a post by someone who straightened their old bent hinges, only to have them quickly deform again. If I remember science class, once metal bends it will more easily bend the next time. Except, old iron, which doesn't bend it shatters.

Definitely those side strips must be aligned correctly to position the metal pieces at the right place.

battmann

iTrader: (9)

i contacted Hawks to ask about their hinges and if there were any additional instructions / tips for installation. i included links to the couple threads on TGO about the glass shattering after installing them. i bought these hinges awhile ago but haven't installed the hatch on my project car yet. the last thing i want is the hatch breaking and scratching the fresh paint. Hawks reply was that the problems in the TGO threads was definitely installer error. the only instruction they gave was to tighten the body side bolts with tools but the hatch side bolts should be hand tight.

sklearman

Based on how easy it was to loosen the four hinge to glass bolts to clean up the broken glass, I'd say the shop only put them hand tight. Over-tightening would not seem to be a factor.

sklearman

Hey all -- I called and spoke to someone in tech support at Hawks. According to him, the very first time they put their new billet hinges on a vehicle, and torqued to spec, it shattered. After that they starting torquing only to 8 ft lbs at the hinge to glass location and haven't had an issue since.

Also, since there is a growing demand for new glass again, I emailed Pilkington which used to make aftermarket back glass and suggested they restart production. I also gave this information to Hagerty Insurance (while my claim is in process) and suggested Hagerty reach out to Pilkingon since they carry more weight than me. My rep said she put it in an email up to her superiors so we'll see.

skinny z

Very thorough and well done.

sklearman

Thank you kindly! We're all here to help each other out. I know the pain I'm going through trying to figure out why my glass shattered, obtaining a replacement, and how to install (e.g. go back to factory hinges) w/o having a repeat.

1989karr

Honestly...as a popular car gets older the demand for parts increases but that's when they STOP making repro parts... ugh lol i hope they make them!!!


Any luck n your hunt??

sklearman

Hagerty is working through "Glass Seekers" to find a shipper for the new glass I found in NH. I put it out twice on UShip and got no interest. It's not like they don't ship windshields and glass for commercial buildings every day across the USA. If we can't find a shipper.....it will have to be a 30 yr old salvage. I found a source for those. In that case, I'll be opting for a hatch with the traditional KITT wing instead of the wraparound...those are heavy, and the rubber rotted.

1989karr

no interest in the fiberglass repros ?


IMO though they arenr;t very secure...they say to drill in screws that would attach to the stock mounting areas though.

sklearman

If I replace hatch with an OEM rubber aero wing, it's just going to have to come off immediately. That's more expense. If I get a salvage hatch with the traditional wing, it's just a paint job (hopefully) and there's less weight pulling and twisting on the glass. If I get the new glass and keep my existing components, I will likely have the shop remove the rubber wing and just go without until money allows for a Hawk's fiberglass one. The fastener clips on my original literally turned to dust. You can't get them anymore to my knowledge and without a couple at least, the wing might not fit right or want to lift while driving.

1989karr

"The fastener clips on my original literally turned to dust"

Are you talking about the aero wing "brackets" that are on the glass metal trim?

sklearman

Yes. They connect the metal trim around the glass to the wing. All six of mine pretty much turned to dust. I think the stress from the shatter finished them off.

1989karr

Ahh i see i see.



I like the look of the wings lol


but the KITT spoiler is cool too!

Or you could technically do that other style from the camaro...the high rise one.......I THINK those only had the light up inside the glass though. on 91 / 92s?

sklearman

True but I think the Camaro spoilers are for the Camaro....although the Gen II Trans Ams looked pretty sharp with something similar!

1989karr

Or you could even go and do a 4th gen one,...thats kinda wild imo though lol

sklearman

Nah, if not the aero wing I'll stick to the KITT one. I'm old school!!!

1989karr

niceeeee

USMC3782

funny you mention that I have one for that reason getting ready for paint

sklearman

Terrible quality video from the 80s I think, but at 46:15 the glass seems to explode as the installer was adjusting it on a Gen III. Seems this problem goes back to Day 1.

1989karr

Daaannngg...sure looks like it!!!!!!

1989karr

The red cars appear to have the aero spoilers though...painted at 47: something......so im guessing this is in like 86 to 89?

1989karr

What in the world was the guy with the wrench doing?? he was going at it pretty hard kinda carelessly.....

sklearman

Supposedly this was 1987 right before the Norwood plant shut down. I'm sure there's plenty of carelessness on the part of the workers. At least we know this has always been a problem right at the factory.

1989karr

oh crap, mines an 87 lol


anyway to tell where the car was produced?? hahaha

sklearman

Yes my friend. Look on this site, just match the year and the correct number/letter in the VIN up. http://www.transamworld.com/3genvins.php

1989karr

thx! def gonna check it when i get home!

1989karr

any updates?

sklearman

Still waiting for the hatch to magically appear at the body shop. It's shipped, but who knows where it is right now, or when it'll arrive here.

1989karr

looking forward to the updates!

BTW, what hinges did you decide to go with?


I checked my hinges and found that they both have that bow in the middle which I think wasa design

sklearman

I've never found a set of originals so Hawks billet it must be. I spoke directly to Hawks and they said to be sure not to tighten hinge to glass location more than 8 ft lbs. That's much less than factory spec which is I think 11-14. Not sure about the bow. I have seen pics both with, and without it so I don't know if GM changed the design at some point or what. The mystery remains!

1989karr

I need to replace one of the THROUGH THE GLASS bolts cause its hideous and rusted on top the glass lol ugh...


Problem is one seems tight / rusted?? i dunnt....im scared to remove it haha


did you have problems removing the original nuts?

sklearman

With the originals, only 1 of 4 would come loose. The other three literally spun around inside of the black cap you see on the top of the glass (stupid design IMO). Body shop had to carefully cut the bolts out. A friend suggested putting pipe thread tape or something on the through-glass bolts to keep metal from touching glass. Not sure if that's needed but it wouldn't hurt.

1989karr

ahhh good to know, thanks!!!


I think i'll just take it to a body shop once I get to that point.

1989karr

1989karr

this is mine for the record

sklearman

It might be easier to let a shop do it. If they will. Mine was very hesitant due to possibility of the glass shattering. Soon yours will be concourse level mint again! Those wheels are what I had on my 86, I still like that look better than the crosslace on a Gen III.

1989karr

lol thx! this is my 89 with a 3.4 V6 on it

Im gonna paint it a nice dark blue and silver like my truck haha and throw a KR nose on it. I like the look and the YELLOW scanner light haha


I hope I can find a place..my shop i usually go to seems to chicken out from things lately....i have rust in the cowl so i'll probably need to weld it myself so i need to pul lthe dash....

.my cap was so rusted the plastic part came off so its exposed ugle metal or whatever... im scared of the glass cracking though...hard to find here in hawaii.

Strife6986

It might of been brought up...

Just a Thought, but those who are having their hatch glass bust, Has anyone figured in the seal is molded(over time) to the shape of the old glass placement and while shut there is uneven pressure causing the pop?

Abubaca

iTrader: (3)

So I've been following along, and wanted to throw out an observation/question pertaining to the rear decklid overhang. My glass is in good shape, hinges appear tight and I'm having no issues. I DO however have the typical overhang. I saw where it said that it was believed this is typically a hinge issue and NOT a decklid slipping on the glass issue. I can't how see the hinges bending could account for this much movement. ??? I get that it would throw off "perfect" alignment, but many poeple have as much as a quarter inch or more!

Do we feel comfortable saying that there are possibly many factors that contribute to the decklid overhang? Seeing the trouble many of you are having with hinges, and the fact that I hope the car will see some track time, I may just let the overhang stay, assuming it can't be fixed by repositioning the glass/decklid or the body side hinge placement.

Reddragon88gta

I agree that there could be several factors, the one that finally cured mine was getting the proper hatch struts. Too strong and they will push the deck lid out.

Abubaca

iTrader: (3)

So your decklid DID move then??? My glass to body gaps look about perfect all the way around, but the decklid is about a quarter inch farther back than the edge of the quarter panel. Sure LOOKS like it's the decklid and not the hinges.

Reddragon88gta

I went through replacing the hinges, moving and re-sealing the deck lid which did not eliminate it. Finally I researched the various pressures of the hatch struts and chose the weakest one off rockauto, AMS4967/ no spoiler and no wiper, which once installed improved the overbite. Those struts don’t shoot the hatch to the moon when opened and can easily hold the hatch up. The only rub on those struts is I had to swap over the plastic bushings where the strut mounts to the deck. Also keep in mind my GTA has the fiberglass spoiler so much lighter.

The replacement struts I had before were strong arm brand for spoiler( we’re very strong and could lift hatch without help) and it was a noticeable over bite and now it’s almost gone. If when I resealed the deck and followed the FSM to the letter and pushed the deck in slightly more than perfectly flush( which I did not) it would be perfect I think. So as it sits now is close enough for me and my OCD ( it’s a third gen too so these cars panel gaps were never laser perfect lol)

The one thing I’ve taken away from this is your on the right track by checking the body to glass gaps etc. because each car is different…some the hinges might be bad, others the urethane on the hatch might have gotten loose/deteriorated, or the aftermarket hatch struts are too strong.

skinny z

Yes. Not the least of which is something one of the body men I knew filled me in on when he was examining my 84 Z prior to some damage repair ( 20 years ago). I asked about the uneven gaps, the overhang of the hatch and the crooked three piece spoiler and his reply was, "Good old GM build tolerances back then.".
So, yeah. Lot's could be going on.

Abubaca

iTrader: (3)

I edited my initial post. I said my deck sat an inch over! That's a lot! ...it's a quarter inch...maybe 3/8". On my 89, I was able to move the hinges on the body side about 1/8" and that was all I needed. I don't think I'll get that much out of THIS one though! Looks to be too much. My struts are very strong, so I may look into that P/N you listed....thank you. ...I'm also gonna check that decklid, but at this time, I don't feel like attempting to fix/replace the hinges, IF it turns out that they're the problem. I'd rather just live with the overhang, at least on this car.

Abubaca

iTrader: (3)

Back in 90 or 91 (guessing here) one of the employees where I worked after high school had what was probably a California Iroc. True Cali Iroc or not, it was low miles, immaculate, no spoiler and boy did I want that car! Anyhow, I distinctly remember the hatch overhang!

ughmas

Interestingly I ordered the AMS 4967 struts and they shoot my hatch to the moon, I can't open it with the button because it will slam upward 90 formula with fiberglass spoiler.