The diff crossmember is not the weak spot on these cars. Beware.
1972 rear crossmember
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From: Manchester NH
1972 rear crossmember
Hey everybody......
I've got a 1972 I'm looking at and the guy says the frame is good with the exception of the rear crossmember. Won't pass inspection. I'm waiting on pics, but is this a big deal? Sorry for being a frame newbie. I just don't want to get myself in a hole.
Thanks!
I've got a 1972 I'm looking at and the guy says the frame is good with the exception of the rear crossmember. Won't pass inspection. I'm waiting on pics, but is this a big deal? Sorry for being a frame newbie. I just don't want to get myself in a hole.
Thanks!
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From: North of Toronto - Ontario
Well if it's the crossmember that the rear differential is bolted to, it's a pretty big deal, spring is connected to the diff, lower strut rods are connected to the diff. so if the crossmember is sketchy and the diff is connected to it and everything else is connected to the diff....
Here's the crossmember with just the diff attached
That being said, the cross member did have a tendency to fill full of crap and disintegrate so just because it's bad doesn't mean everything back there is bad.
Bit of a job to replace since so much is attached to it but certainly doable
Replacement crossmembers are around and not too crazy in price
Mooser
Here's the crossmember with just the diff attached
That being said, the cross member did have a tendency to fill full of crap and disintegrate so just because it's bad doesn't mean everything back there is bad.
Bit of a job to replace since so much is attached to it but certainly doable
Replacement crossmembers are around and not too crazy in price
Mooser
Last edited by Mooser; May 17, 2012 at 09:56 PM. Reason: Add more details
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From: Manchester NH
Well if it's the crossmember that the rear differential is bolted to, it's a pretty big deal, spring is connected to the diff, lower strut rods are connected to the diff. so if the crossmember is sketchy and the diff is connected to it and everything else is connected to the diff....
Here's the crossmember with just the diff attached
That being said, the cross member did have a tendency to fill full of crap and disintegrate so just because it's bad doesn't mean everything back there is bad.
Bit of a job to replace since so much is attached to it but certainly doable
Replacement crossmembers are around and not too crazy in price
Mooser
Here's the crossmember with just the diff attached
That being said, the cross member did have a tendency to fill full of crap and disintegrate so just because it's bad doesn't mean everything back there is bad.
Bit of a job to replace since so much is attached to it but certainly doable
Replacement crossmembers are around and not too crazy in price
Mooser
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Race Director
Joined: Apr 2011
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From: North of Toronto - Ontario
Some "normal" areas are the aforementioned birdcage where water ran and sat, rad support (similiar thing with water sitting) this crossmember (not so much water but whatever it was made from seems to flaking) the #4 body mount (rear wheel flung stuff at it forever)
Some are an easy fix, some are a giant hole at which you can through money at for a long time and never actually fill.
Careful, pretty cars can affect your judgement
Mooser
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Burning Brakes
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From: Middlesex NJ
You need to get under there and look for yourself.
Get us some pics and post them.
If its the differential crossmember thats truly bad then I can almost guaranty your side rails and the #3 crossmember will be toasty as well.
I'd like to know what "inspection" he means.... does he mean DMV inspection?
Get us some pics and post them.
If its the differential crossmember thats truly bad then I can almost guaranty your side rails and the #3 crossmember will be toasty as well.
I'd like to know what "inspection" he means.... does he mean DMV inspection?
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From: Manchester NH
Just spoke with John from John's Corvette in Laconia. He said that if that crossmember is rusted out so is everything else, and not to go near it. He did all the work on my '80. Do you guys agree?
Melting Slicks
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From: Space Coast Gator Territory
I've worked on rusty frames, but the differential cross member's were in decent condition. If it is badly rusted, I don't see how the rest of the frame went unaffected. Ask to pull the kick panels and look at the #2 body mount. Kick panels are to the right and left of your feet. If there is rust in the windshield frame, it will show up down there. Water leaks past the seals, gets into the windshield frame and runs down the A-pillar. The result of this shows in the kick panel. Cars stored in a garage and only driven in good weather were spared from this happening. As already said, if there are signs of excessive rust, best to pass. The trick is to know what is excessive rust and what is manageable. They will all have some rust, as these parts were not coated with any protection from the factory. Good Luck!
Last edited by Red 69; May 18, 2012 at 01:32 PM.
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From: Manchester NH
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I've found it's not the crossmembers that go first, it's the brackets on the frame that they bolt to. They're pretty thin material, and have quite a bit of downward stress on them on the drivers side. A actually broke one that was rusty after an exhuberant stomp on the throttle! Whole rear end assembly came down and hooked itself in the wrong position which made the car 3 inches higher on that side! 
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From: Manchester NH
Well guys thanks for the help, but I passed on this one. Even after the guy lowered his price 25%. I don't think he was a scammer just didn't know what he was buying.
Sooo.....I just purchased a 1980 L82 !!!
http://forums.corvetteforum.com/c3-g...9-im-back.html
Sooo.....I just purchased a 1980 L82 !!!
http://forums.corvetteforum.com/c3-g...9-im-back.html