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1995 Cadillac Fleetwood Brougham
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Discussion Starter · #1 ·
Herroh,

I am working on a front brace that uses the sway bar holes, like the "F-body brace". However, mine will be more extensive and will bolt to the vehicle in additional locations.

Picture a triangle, with the 3 points being each sway bar mount and then the thing in the center of the engine cradle.

I might try to run something up to the horizontal bolt holes in the frame for the steering linkage. We shall see.

Kazaam.
 

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It sounds like a new wrinkle of sorts on the old 'jounce bars' for calming the flex in the frame horns. My black car is currently under two covers, so I just now eye-balled my (hopefully similar) Fleetwood. So this, quote "thing in the center of the engine cradle" - is it the rad support (which don't look very structural)? Or, is it just the front crossmember?

And just to get a hint of the triangulation strength, if Points B and C are the sway bar frame connections then about what's the length of 'h' between Points A & M? Just roughly.

Triangle Slope Rectangle Parallel Symmetry
 

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Thank you for taking this on. Always interested in ideas to make the frame more rigid. I have the F-body brace and it makes a significant improvement, but some sort of triangulation with gusseted angles would likely be even better. If it will use the sway bar mounts, I suggest incorporating permanent frame studs into the plan instead of the easily-stripped holes (switching to threaded studs has been on my list forever).
 

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Discussion Starter · #4 ·
If it will use the sway bar mounts, I suggest incorporating permanent frame studs into the plan instead of the easily-stripped holes
Bingo!

Great minds think alike.

I've been imagining something like the Bill Harper or KDS rear shock hardware.
 

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1993 RMW, 1996 RMW, 1992 OCC
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That's been done, there are kits for it (though I can't find any links at the moment). The problem is that there's a bump between the two holes inside the frame rail, so anything you put in there can't sit flat against the surface. That bump needs to be ground away, and that's very difficult to do.

I installed these on mine:

The holes are slightly farther apart to more easily accommodate different sizes of swaybars. Works great, looks good:

 

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Discussion Starter · #6 ·
The problem is that there's a bump between the two holes inside the frame rail, so anything you put in there can't sit flat against the surface. That bump needs to be ground away, and that's very difficult to do.
:unsure:

A U-bolt wouldn't sit flat against the surface.
 

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The inside surface, where the U would sit. By tightening the nuts, you'd be bending the flat part of the U over the bump and distorting the U-bolt. Not to mention that the pressure wouldn't be distributed evenly
 

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Discussion Starter · #8 ·
The inside surface, where the U would sit. By tightening the nuts, you'd be bending the flat part of the U over the bump and distorting the U-bolt. Not to mention that the pressure wouldn't be distributed evenly
I'm having trouble identifying "the flat part" of the letter U.
 

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This is the U-bolt you're referring to regarding the KDS rear shock hardware. It's flat



The flat part can't lay flat inside the frame rail between the two holes of the swaybar mount. The U-bolt would get distorted by the bump unless that bump was ground off.
 

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Discussion Starter · #10 ·
What if the U-bolt was actually shaped like a U?
 

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Then it would either distort horribly the moment any stress is applied to it, thereby pulling each side longer, or it would cut through the frame.

Honestly, considering how difficult it is to get inside the frame rails in the first place, at that point you'd be better off installing M10 wheel studs in there. For me, it was way less work to drill out the holes and weld in those plates that have grade 8 hardware
 

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Discussion Starter · #13 ·
Then it would either distort horribly the moment any stress is applied to it, thereby pulling each side longer, or it would cut through the frame.
I have no idea what you're talking about.
 

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I drilled/tapped swaybar holes to 7/16-14 ,and threaded hardened bolts with extra thick washers from inside frame. Template was for fabricating a steel plate extending from one side to the other. Sandwiched in between frame ,and swaybar mounts. Plus ,it provides a flat surface for them.
Hood Motor vehicle Automotive tire Electrical wiring Automotive exterior
 

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This was something i've always wanted to do, but I wrestle with the idea of adding more weight to the nose of the car and how much this would actually be worth it. If I didn't already have a very heavy iron LSX block and a 75lb supercharger I may consider it more but out of all the chassis reinforcements I have done, this has been the one I have passed on.

Tying it to the sway bar bushing mounting area sounds like a good idea, but I also wonder if a simple 3/4 .090 wall bar welded across the frame rails, perhaps up by the front bumper, could do just as much as any of this to make the frame horn area more rigid and do so without nearly as much weight as a triangulated setup.

You'd basically have the engine cradle at one end and a welded bar at the other. I can't see the horns moving too much then.

On my car, I actually welded the bumper impact shocks so they no longer move (basically turning them into a solid mount). I did this because any movement there could affect my heat exchanger which is mounted up front with very close tolerances. In the end, the bumper and bumper shocks are still BOLTING on which isn't ideal for increasing rigidity but it still helps make much better use of that giant chunk of heavy steel already sitting at the front of your car. Without welding those shocks up, the whole thing is free to flex on them and really does nothing for rigidity.
 

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Also, not sure what the issue with the sway bar hardware has always been? Am I the only one that didn't find it too difficult to fish nuts/washers over the sway bar bolts? Been a while but I'm pressure sure I just did what I always do for stuff like that, painter's taped the nuts to a long piece of very thick soldering wire, bent the wire as needed and fished it in from one of the holes in the chassis or the front opening.
 
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I have no idea what you're talking about.
I don't think he's realizing that the nut portion on the U bolt would be fixed (the threads wouldn't extend past the part where the two legs of the U come out of parallel). .

Think of it as just two studs attached by a U over the top. The nuts sit on the threaded legs which sit parallel and all the clamping forces are between the nuts and the end of the leg, you aren't pulling the U portion down into the chassis, it's just there to connect the top of the studs for ease of assembly. Wouldn't matter if it's a true U or shaped like the shock hardware, as long as the legs are parallel and the nuts are on that parallel portion.
 

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Discussion Starter · #19 ·
Tying it to the sway bar links sounds like a good idea
Not sure I follow. The sway bar links are a moving part, and the frame should not be.

Welding steel across the frame is absolutely the "best" way to do this, and that's what I would do if I were building an individual car.

In this case, my goal is to bring a product to market that can be installed by the average Joe. Welding optional.
 
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Not sure I follow. The sway bar links are a moving part, and the frame should not be.

Welding steel across the frame is absolutely the "best" way to do this, and that's what I would do if I were building an individual car.

In this case, my goal is to bring a product to market that can be installed by the average Joe. Welding optional.
Ooops, that was a typo, I meant sway bar bushing mounts.
 
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