We're all familiar with the deck lids on these cars being misaligned and having a bit of an overhang, sometimes a little, sometimes ALOT.
I have a theory as to how this happened. . .

When you order hatch struts for these cars there are multiple options to choose from (spoiler, no spoiler, rear wiper, etc. etc.). My theory is based on the assumption that each different strut option has a different lifting capacity (similar to fiberglass vs steel hood struts).

I would wager that installing any of the stronger hatch struts can cause the struts to slowly "push" the deck lid towards the rear of the car, causing the misalignment/overhang. The decklids would have all been torqued down the same amount whether they had a spoiler, wiper, or whatever so the wildcard factor is what struts were attached. (for anyone who hasn't taken a deck-lid off, the deck lid attaches to the rear glass via elongated holes that allow for forward/back adjustment of the lid. The struts attach directly to the decklid.)

"But some came from the factory like that!" - Yes, and I would also guess that, because it was the 80's, the line workers weren't exactly paying attention to what hatch struts went on which cars. I can imagine someone asking for another box of hatch struts, the new guy saying "There's 3 different ones, which do I get?" and someone telling that person "Ah, it doesn't matter, a strut is a strut!"

That's my theory. Think it carries any weight?

 

I had a minor saga dealing with the hatch overhang and after replacing the hinges, attempting to shim the hinges which did nothing (but apparently some cars were shimmed at the factory) taking the decklid off to realign/re-seal all to not fix the problem( however the alignment was perfect with the struts disconnected) but when I reconnected the hatch struts I came to the same conclusion that they are pushing out the decklid.

The solution was I replaced my newish strong arm hatch struts rated for spoiler and wiper with AMS4967 rated for no spoiler and wiper from Rockauto and hatch overhang was nearly completely eliminated ( it would be perfect if I pushed in a little past flush as the Factory service manual recommends) but I will call it close enough. As you mentioned the psi ratings for each strut are different and I went with the lowest one I could find.

One thing to note on my car is I have the Hawks fiberglass aerowing spoiler which is much lighter than factory but the those AMS struts work perfect on my car and look great.

 

NAH...........I still have the weak original OE struts on my 84.
My deck lid is crooked.
Nobody notices it anyhoo.
Unless your one of those "driveway queen naysayers" that is!


So for the extra strong replacement china/mexico junk stretching the lid
from the glass theory dont hold water for me.

NOS replacements are out there and very $pendy.

 

I don’t think you understood my statement. I said that replacements could do it AND incorrect struts installed at the factory.

You are of course welcome to disagree.

 

There are at least 3 causes for the overhang IMO, I just know on mine it was the struts that finally cured it. I have seen some cars where the urethane and butyl separate and that causes it as well as bent hinges.

Each car is different but I do agree these things never had perfect panel gaps from the factory so to expect it 30 years later is a big expectation.

 

iv'e had my TA from day one the hatch always hung over a bit (from the factory) and Iv'e replaced my struts probably in the 36 years maybe 3-4 times.I really don't notice it anymore and when I go to shows ,I always lift the hatch anyway.As long as the hatch closes with the pull down and 3rd brake light works I'm OK with it

 

But the hatch is closed and held in the center by the lock so how would a overstrong
struts stretch the lid crooked on the glass?. Maybe a Friday hatch and glass assembly
job by a lazy employee? Could be many unknown reasons..............

 

The way I verified this theory that it was the too powerful struts causing the overhang on my car was disconnecting them and closing the hatch very carefully( the weight of the hatch being what it is you have to be very careful). Once closed with the struts removed the alignment was perfect, when I reinstalled them the alignment was pushed out.

When I tried the weaker pressure struts the alignment improved. Once again this was on my car and each car is different.

 

So you're suggesting there's some wiggle room in the hinges somewhere? ...how much difference are you talking about? 1/8"? 1/4"?

 

the wiggle room is the deck lid itself, not the hinges. it bolts onto the glass thru oval holes in the glass. Maybe 3/4” long? And those allow for the forward/back movement of the deck lid.

 

...I understand the ovals allowing for it to move, but I figured that was for fitment during installation. Once properly mounted, I wasn't aware of any ability for it to move.

 

yeah it can, those oval holes are the only thing holding it in. It can move as far back as the holes allow as long as some chunk of latch bar can connect.

 

Anyone got pics of the holes for the decklid?


I wonder if you put some kind of rubber grommet to revent the decklid from moving...

 

check the last 30 seconds of this video and you can kind of see them. also this guy does a really good in depth series on deck lid replacement.

 

I'm getting anxiety watching him remove the decklid lol

 

I had always thought this too...some sort of half circle or oval plug to fill in the unused portion of the oval holes.

 

For the record, I just wanna say that the linked video about how to remove/replace the decklid is amazing! Incredibly thorough!!!!!

 

Yes!

KINDA like how the top hinge bolts that go through the glass.... my worry would be any pressure from the decklid moving or whatever that could crack the glass though...

 

A very valid concern. Maybe something whittled from a urethane sway bar bushing, or something similar. Firm enough to hold it's shape against the pressure of the struts, elastic enough to bounce back and return to it's original shape if momentarily deformed, and soft enough to absorb impacts and vibrations to save the glass.

 

I removed mine completely before I painted the car. I spent an absurd amount of time lining it and the spoiler up before paint. Test fit it after paint had my glass guy seal it and install. Of course it all moved and now looks like I never lined it up!! I may now thing its the struts to cause mine was perfect before I put them back on. I never thought they would cause it. Its gonna stay that way now. Im not risking damaging the paint or breaking the glass to fix it. I searched for a non-defrost back glass when I did it to. I didnt want the defrost lines when I tinted it.

 

What did you use to seal it?

They say you need to let the sealer cure a while before reattaching the struts.

 

Im not sure what the glass guy used. Prob some type of urethane glue. I think I did leave it before reattaching everything it was a few years ago now. It irritates me every time I look at the trunk now cause it was perfect. Lol

 

I think the guy in the YouTube video above bought some kind of kit with butyl rope and urethane or epoxy

 

The alignment issue with the hatch is well known on TGO. The hatch struts push back on the deck lid over time and the adhesive used at the factory wasn't strong enough to keep the deck lid from moving. The only fix is to remove the deck lid, clean up the old adhesive, and apply new. Do not use the weaker struts on a car with the spoiler, louvers or rear wiper.

 

Do you know what type of adhesive is recommended?

I was thinking a thin layer of the stuff professional shops use for windshields.... but that stuff hardens really hard and would seem impossible to remove if need be in the future?

 

You can use the weaker struts if you have the fiberglass rear wing but no way with the stock rubber aerowing. I used the 3M urethane and it’s worked good.

 

Just went through this last week. Here is what I used

 

I also have the Hawks spoiler and I am interested to know if when using the AMS4967 strut if it is strong enough to hold up the hatch when using the interior hatch release switch so that the hatch doesn't reclose.
Thanks

 

[QUOTE=TABBOO;6475175]I also have the Hawks spoiler and I am interested to know if when using the AMS4967 strut if it is strong enough to hold up the hatch when using the interior hatch release switch so that the hatch doesn't reclose.
Thanks[/QUOTE

I haven’t really experimented much with that as I don’t open the hatch a lot but the struts have no trouble holding the hatch up when it’s opened.

 

I'm glad I found this thread because I have about 1/4" of overhang on my rear hatch, but it's worse on the right than the left side. It looks like the whole hatch (and not just the decklid) on mine is pushed back because there is a HUGE gap between the car top and the top of the hatch, especially on the right side. I'm thinking there must be something wrong with that hinge; either the pin is worn out or the hinge got bent somehow. Am I on the right track?

 

Take a pic if you can, but it sure sounds like your hinges may be worn out IMO. The Hawks hinges are good but not cheap and if you change them be very careful, a helper would be great.

Also if you recently changed trunk hatch struts that can cause the lid to push out too.

 

On my 89, I had about .25" of play when the 4 nuts holding the hinges to the roof/car are loosened. All four went through oversized square holes. I was able to fix my overhang (like you're reporting) in less than 15 minutes, with a second set of hands. Thought this may ALSO be the case with my more recent 88. The 88 did NOT have the same oversized holes on all four studs. 2 did.....1 only had left to right movement, and one was just right, so no adjustability at the car side of the hinge. That being said, I've concluded that was NOT the source of my problem, as the gap is equal, and I can SEE signs that the decklid has moved. I've purchased the proper adhesives and plan to fix this winter. ....if you can SEE a difference in the gap, trying to adjust the car side of the hinge may be worth a shot.

 

I have the hatch to roof hinge adjusted as far forward as it will go but still have a 1/2" or so gap there, so something must be really wrong. I thought I would take the right strut off and see if I can push the right side forward and backward to find out if there is play in the hinge. I wish it would be as simple as making the adjustments at the bottom of the glass as in the video, but it seems like there is something different that is the (main) problem in my case.

Did GM just use one model rear hatch assembly (including the hinges) for the entire 3rd gen. f-body run? There is evidence of two large stripes being on my decklid, but I can't find evidence of stripes on the hood, like the rear hatch might have been replaced at some point. I was wondering if this might have something to do with my problem, although the gaps on the left side of the hatch seem to be better, which makes me think it might not be this that is making any difference in how it mounts.

 

I would suggest that if the glass itself is physically mis-aligned to the car, meaning larger gap on ONE side than the other, it would HAVE to be a hinge issue. If I may make a suggestion about board etiquette, why don't you start a specific thread. Since it appears your issue isn't the typical misaligned hatch problem, you'll likely get more traction with a new thread. ...that being said though, I don't see how it's NOT the hinges, at least in your case.

 

I considered starting a new thread, but thought what I have going one was relevant to this thread. I certainly wasn't trying to hijack this one. I'll go ahead and start a new thread when I know more about what I think the problem is.

 

Well you're probably right. I wasn't coming at it from any position of authority, I was just throwing it out there. There's no hard and fast rule on when it's relevant, or when it's a different topic. It's all good. ....I AM interested in what you find though.

 

struts stretch the lid crooked on the glass?. Maybe a Friday hatch and glass assembly

 

they don’t “stretch the lid”. The deck lid attaches to the glass via elongated holes in the glass that allow for forward/back adjustment. The struts push all they’re forced against the deck lid, not the glass.

too strong a strut will push the deck lid back in the elongated holes causing misalignment.

 

I know I am late to the party but I just replaced my struts. Before replacement my alignment was perfect. After I have the alignment issue and came to the same conclusion as the original poster. Then I saw this tread.