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Old Mar 7, 2015 | 09:27 AM
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Does anyone have a schematic or a description of the rear chassis construction where the rear trailing arm brackets attach? I've got an 85 and my right trailing arm bracket is flexing. I removed the bracket and found that one of the mounting points is loose (rattling around inside the sheet metal). There appears to be 3 recessed threaded holes where the bracket is bolted and the lower threaded mount seems to have broken loose. I don't want to cut away the sheet metal until i know what i'm dealing with. I'm hoping this can be repaired with a weld. Please help.
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Old Mar 7, 2015 | 11:39 AM
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Originally Posted by ralph
Does anyone have a schematic or a description of the rear chassis construction where the rear trailing arm brackets attach? I've got an 85 and my right trailing arm bracket is flexing. I removed the bracket and found that one of the mounting points is loose (rattling around inside the sheet metal). There appears to be 3 recessed threaded holes where the bracket is bolted and the lower threaded mount seems to have broken loose. I don't want to cut away the sheet metal until i know what i'm dealing with. I'm hoping this can be repaired with a weld. Please help.
Has the nut plate fallen off or is it just loose and you can't secure it to tighten bolt? The bolts I believe are M12 X 1.75. I've never had a situation similar to yours (in this location) but I believe I've seen it mentioned before. It seems you're likely quite talented so I don't believe you would have any trouble fabricating a nut plate. If you had access to a pneumatic nut-sert install tool I'd be tempted to do a nut-sert. I've repaired similar with J-nuts, nut-serts or just slotting the rail to allow holding the nut with an open-end wrench.

In this link you can see the nuts:

https://www.corvetteforum.com/forums...post1584187316

Since you mention it's the lower I'd think there are a few options.

Good luck - this post will at least keep you towards the top.
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Old Mar 8, 2015 | 08:14 PM
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Thanks for the link to that other post. Mine is actually a 4-link bracket (I have a solid rear in the car), and there are no pads that fill the voids. It's just a flat bracket. The nut plate, as you call it, is still in place, it's just loose. I can tighten all the bolts fine, but bracket is flexing. The sheet metal is cracking and there doesn't seem to be much support behind the sheet metal. Now i'm thinking that adding pads to fill the voids, like on the stock and DRM brackets will help. I'm also planning to weld a plate to the frame, horizontally near the bottom of the 4-link bracket, then weld a tab to the 4 link bracket and bolt it to the plate. Then the 4 link bracket will be fastened in multiple axises.

Can anyone tell me how thick those pads are. I'll get some sheet metal to match and weld the pads to the back of the 4-link bracket, the like the DRM brackets.

Last edited by ralph; Mar 9, 2015 at 11:59 AM.
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Old Mar 9, 2015 | 04:26 AM
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Originally Posted by ralph
Can anyone tell me how thick those pads are. I'll get some sheet metal to match and weld the pads to the back of the 4-link bracket, the like the DRM brackets.
Just put a "straight edge" over yours and measure for your particular application, I wouldn't use dimensions from the DRM product to construct yours.

I'd say if you've a flexing issue with your plates it's likely the fault of the plates you're using\constructed. I'd say with a four link and a solid rear you need to rethink the entire attachment to chassis.
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Old Mar 9, 2015 | 11:58 AM
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Yeah, I know i could measure it, but I'm only going to get one day at my buddy's shop to make the repairs. I was hoping not to have to tear it apart again until i get to the shop, and I want to have all the parts/materials before I go there.

The 4 link bracket is 1/4" steel. The bracket is not flexing, it's the car/frame. See my earlier post for the other modification i'm planning.
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Old Mar 9, 2015 | 12:36 PM
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Originally Posted by ralph
Yeah, I know i could measure it, but I'm only going to get one day at my buddy's shop to make the repairs. I was hoping not to have to tear it apart again until i get to the shop, and I want to have all the parts/materials before I go there.

The 4 link bracket is 1/4" steel. The bracket is not flexing, it's the car/frame. See my earlier post for the other modification i'm planning.
I put a straight edge over an OE bracket and I had a piece of I believe 12 ga strap. It wasn't snug but offered resistance, 12 ga is .109 so I don't believe I'd start with anything greater than 11 ga. 11 ga is .125 or 1/8. 10 ga is .140 and I don't know that it might work and fill the depressions. Buy both and try!
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Old Mar 9, 2015 | 12:49 PM
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Originally Posted by WVZR-1
I put a straight edge over an OE bracket and I had a piece of I believe 12 ga strap. It wasn't snug but offered resistance, 12 ga is .109 so I don't believe I'd start with anything greater than 11 ga. 11 ga is .125 or 1/8. 10 ga is .140 and I don't know that it might work and fill the depressions. Buy both and try!

Thanks......that was helpful.
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