Rear hatch gap alignment help
 

Hi all. Recently got an 87 trans am. Something appears "off" on my rear hatch. Can anyone tell me if I need to adjust the hinges, missing something, or other? Appreciate any help
https://cimg8.ibsrv.net/gimg/www.thi...214467f8bb.jpg
https://cimg9.ibsrv.net/gimg/www.thi...51abd5bf42.jpg
https://cimg0.ibsrv.net/gimg/www.thi...205f644c2c.jpg
https://cimg2.ibsrv.net/gimg/www.thi...34c290bf9c.jpg
https://cimg4.ibsrv.net/gimg/www.thi...762ac4187e.jpg

Re: Rear hatch gap alignment help
 

Well, this is a hot button issue on here with a few theories on why this happens. Some popular ideas are the original hinges get “bent” with age/weight of the hatch, another is the urethane that attaches the decklid to the glass degrades and gets loose and will let the decklid slide back, also if the hatch struts were replaced with new powerful hatch struts they can push out the lid, and lastly that you need shims underneath the hinges. If you do a search you will see all that and more as well as some solutions to the issue.

Just looking at your pics you might be a candidate for new hinges from Hawks but I’m not an expert. Be sure to take your time and try to find the source of the issue first and be careful when working with that glass.

Some common fixes are shims under the hinges, removing the decklid/repositioning it and resealing with high strength windshield urethane/butyl etc, new hinges, and proper strength hatch lift struts. There is a little adjustment that can be had at the hinges but not enough for your gap IMO.

Re: Rear hatch gap alignment help
 

The pic was prior to replacement struts. the new struts are pretty difficult to close the hatch. Do they need to "break in" a little? Or did I get wrong strength? I believe I ordered right kind, but as you can see I'm missing my spoiler. Can the spoiler really add that much weight?

Re: Rear hatch gap alignment help
 

The factory spoilers were pretty stout being made of rubber, I replaced mine with a fiberglass one from Hawks and it’s a lot lighter. If you have plans for a new spoiler etc I would run the AMS4967 from rockauto. Those struts are what I imagine factory strength was or at least close. The classification for those is without spoiler or wiper, I had the ones for spoiler cars and it was too strong and even pushed my deck lid out. After swapping to the 4967s it went back to normal. Also keep in kind I did new hatches and re-sealed the hatch as well.

Re: Rear hatch gap alignment help
 

The most common issue is worn and bent hinges like these:


https://cimg8.ibsrv.net/gimg/www.thi...9e5e7814b.jpeg
https://cimg9.ibsrv.net/gimg/www.thi...baf849d2a.jpeg
https://cimg0.ibsrv.net/gimg/www.thi...e262ec5a0.jpeg
https://cimg1.ibsrv.net/gimg/www.thi...9ed8fbef3.jpeg

Re: Rear hatch gap alignment help
 

ouch, i see, poor hinges lol. Id say thats def gotta be the issue. Well, unless i can find some cheap original hinges in good condition, itll be what it is for now. If I get the car to be a solid cruiser, Ill purchase the billet hinges.

Re: Rear hatch gap alignment help
 

Just an update, swapped to the 4967s, and no difference. Not sure if it is due to my failing hinges or lack of spoiler. I ordered a replacement hatch w/ spoiler from a local junkyard for $100. Its not the same style spoiler as the one that should be on my car, but for now itll do. And hopefully the weight will help with the struts.

Re: Rear hatch gap alignment help
 

The lack of spoiler at this point won’t affect the alignment. Does the other hatch you are picking up come with hinges? If so they might be in better condition than your current ones. Especially if it’s the pedestal spoiler that came on base Firebirds seeing as how much lighter it is than the aerowing your car came with.

Re: Rear hatch gap alignment help
 

Not cheap, but these are out there: https://www.hawksmotorsports.com/82-...h-hinges-pair/

Re: Rear hatch gap alignment help
 

The bolts through the glass at the hinges and the bolts through the glass at the deck lid have play in them. Since your gap at the top is not right I would start at the hinges. The hinge to body bolts have some side to side adjustment. Start by inspecting the hinges for signs they are bent and replace as needed. They were also shimmed from the factory the shims between the body and the hinge not only lifts the glass in alignment it also pulls it forward due to the angles involved. So once you have the glass level with the car and centered move to the hinge to glass bolts. These are big round holes in the glass and you have about 1/4 of inch adjustment here. If the overhang is still not right move to the deck lid. It isn't urethane from the factory it was a butyl type sealant.

I'm currently going through this process on my firebird but painting stuff and life is slowing me down.
https://www.thirdgen.org/forums/body...ml#post6425748

just be aware its glass don't over torque anything.

Re: Rear hatch gap alignment help
 

Great detailed video on this topic. The guy gets really into it but its filled with great info and advise.

Re: Rear hatch gap alignment help
 

pretty good video. A few things. There is no reason to drill out the holes bigger unless you are making up for bent hinges.

He should of put the butyle tape further back on each side where the globs are. The adhesive he used isn't needed in addition to the butyle and if you use it it's only to keep it from sliding over time but use it sparingly so you can use a piano wire to cut it off if need be in the future. So I plan on only the outside of the bolts, Also the windshield adhesive needs glass primer to stick well to the glass. The bead in front of the butyle pushing out would annoy me especially with my car being white.

When lining up the deck lid put tape from lid to glass then cut the tape so you have side to side reference in addition to front and back.

​​​​​​It's also easier to put the hinges on the car then put glass on.

​​​​

Re: Rear hatch gap alignment help
 

I widened my holes a bit too for the hinges. My hinges are in really good shape. I did what he did but did not overload the butyle. What is the glass primer you mention please? I have to do mine over again and want it right this time.

I thought of that too using tape to keep the side to side in line as you said, and I did that the first time.

Being I have to do this all over again frustrates me to know end. But I had really strong shock supports that were used for the factory aerowing. Now that I have a fiberglass one, they pushed out the deck. I have since changed them to kind that are used for single wing or no spoiler.

Have you done yours yet? I am wondering about the 11ft lbs regarding tightening the bolts on the glass side. I am going to buy and updated 3/8 torque wrench. Last time I tightened and guessed. I am so concerned I may shatter the glass.

Re: Rear hatch gap alignment help
 

https://cimg9.ibsrv.net/gimg/www.thi...d267ca09b4.jpg
3m 08682 windshield adhesive primer.

I haven't tightened it down yet. I've painted the deck lid and spoiler will paint the metal surround and assemble it this weekend. Painting the spoiler kicked my but all the tight curves made it hard. Also my spoiler was in primer for 20 years and had a chip out of it where a branch fell on it years ago.

The book says 11ft-lbs. 0r 132 inch lbs. I will use my inch pound wrench as I don't trust ftlb wrenches at the bottom end of the scale.

The torque isn't likely to break the glass but dirt, burs, etc trapped between will cause a stress riser and shatter it

Also the fiberglass spoiler doesn't effect the lid being pushed out as it happens over time in the closed position, what the fiberglass spoiler allows is using the weaker struts which is less likely to push it.

Re: Rear hatch gap alignment help
 

Thanks, where do you put the adhesion again? Bit confused on that.

I just bought a 3/8" ft lb socket drive. I have an inch one as well. Just nerve racking.

Weaker struts are in order if you use a fiberglass aerowing. The stock on is MUCH heavier. So I replaced mine that were stronger for the stock spoiler with weaker ones. Tim will tell. Just hate having to do it all over again. ARRRGGGHHHH Thanks for the heads up on the primer!