Sway bar modifications

69427

The Artist formerly known as Turbo84
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Clinging to my guns and religion in KCMO.
I've got a (rear) sway bar that looks like it might be workable with the new suspension. I don't have a rear bar on the C4 suspension conversion, and last week's activities showed I need a bit more rear roll stiffness. I have a 5/8" bar that has been sitting on my shelf for several years, originally intended for my street rod truck, which also has a C4 suspension. To make the bar fit, I need to tighten up the bend where the arms start. The bend currently looks like about 75 degrees, and I need 90 degrees. I'm not a metallurgist, so I'm a bit shy about the usual method of adding heat when bending metal. I'm kicking around making a fixture, and then using my hydraulic press to try to bend it. Will it bend, or just spring back? Anybody ever modify a sway bar before? I'm pretty sure I'll also have to do some modifications/welding on the arms afterward (to allow multiple attachment points), but the welds will be minor, and away from the actual torsion portion of the bar.

Opinions, experiences, suggestions?
 
It will bend if you torch it.Since you are bending at the bend it's not a real problem that the spring steel characteristics change. Whatever you do, don't quench it. Also, be careful with forcefully bending it, if you knick it or otherwise start a hairline crack it could get ugly.

Have you considered a speedway bar with custom arms? They can be had in most any sizes.
 
I managed to get a incomplete stock 7/16? sway bar without links...

so I just heated and twisted the ends to accept the same type kit as used on the front ends....been on there some years now....

:D
 
We make our own bars in a steel called "Stressproof". Bend them in a conduit bender and they seem to last fine...
 
It will bend if you torch it.Since you are bending at the bend it's not a real problem that the spring steel characteristics change. Whatever you do, don't quench it. Also, be careful with forcefully bending it, if you knick it or otherwise start a hairline crack it could get ugly.

Have you considered a speedway bar with custom arms? They can be had in most any sizes.

Yeah, I looked in my Speedway catalog, but the ones I saw were a bit pricey. In the event some lower cost items don't work out, I'll take another look at the custom stuff. Whenever I have the opportunity, I prefer to use stuff that looks stock. It's just a thing I have. I get a kick out of some clueless types who look under the car, and comment how lucky I was that "everything just bolted right in". LOL
Perhaps I'll try just a touch of heat on the bends, and see what happens.
 
I know the addco bars are cold rolled but the ends are heated when they make the correct style mounting point. You could use heat but be careful like Twin Turbo said.
 
Well, I've got the arms bent so that they are inward toward the knuckles (versus outward originally), and the ends have been cut off, as I'm planning on welding on some multi-hole adjustment lengths onto the arms. Right now the difficult part is the shape/design of the link bracket that attaches to the knuckle. Due to the suspension being narrowed, the knuckles are directly under the frame rail, and the sway bar obviously has to swing outside the frame rails. So, right now I'm trying to figure out how to fabricate a bracket on the knuckle that won't have severe cantilever issues. The knuckle has a lot of round surface to it, and isn't conducive to drilling new holes. So, right now the progress is slow until I figure out a bracket shape I like.
 
Just a couple pictures on what I'm trying to work with. As I mentioned above, the original mounting holes in the knuckle for the sway bar link bracket are positioned under the frame (just ahead of the spring hanger bolt). However, the sway bar, along with the swing arc, is necessarily outside the frame rail.

IM001196.jpg

I've got a few ideas mocked up with templates. I'm not totally happy any of them, as issues such as bracket flexibility and complexity keep popping up. I'd like to reuse the original bracket holes, but I would need an outer attachment point to eliminate bracket bending during cornering. I haven't found an easy outer attachment point yet. The original bracket location does impart the bar forces directly above the axle centerline (which I prefer), but that also requires having a bar with long arms. Long arms then require having a thicker cross section to keep the same torsion rate. Thicker cross section then means more weight. I'm trying to not add heavy components if I can.

IM001198.jpg


I'm trying to determine if there are any issues with having the bracket location rearward of the axle in a C4 suspension. In a C3 application, the rearward position of the bracket makes the bar a bit more efficient, as there's slightly more bar movement than wheel movement. The C4 suspension has a virtual trailing arm system, and I'm still trying to make sure there's no binding issues (or other down sides) if the bar forces are behind the axle.
 
Well, after a crap load of cutting and grinding, I still haven't come up with a (sway bar link) bolt-on knuckle mount that I'm happy with. There's either too much twisting or cantilever action for my engineering tastes, and I didn't care for the aesthetics either. So, I've changed directions. I've gone back to the original C3 rear bar, and I'm looking at welding a bracket to the knuckles to attach the swaybar links. Here's the rough setup using the stock C3 link (which will be replaced with adjustable heim joints) and the C4 bracket to show the concept. A custom weld-on bracket will be used.

IM001212.jpg

With the sway bar slid as forward as possible (done after this particular picture was taken), the knuckle bracket would be welded to some significant mass of aluminum. Anybody see any issues with doing this (outside of me finally getting around to learning to weld aluminum)?
 
Did you do it?

I have the same issue. I cobbled up a different sway bar link but didn't like it. The factory set-up hits the frame on rebound. I thought of just heating the C4 bar and bending it out a bit and reworking the mount to the spindle. Looks like your set up may be a bit narrower than mine though. What did you decide on?
-Thanks,
Charlie
 
Well, after a crap load of cutting and grinding, I still haven't come up with a (sway bar link) bolt-on knuckle mount that I'm happy with. There's either too much twisting or cantilever action for my engineering tastes, and I didn't care for the aesthetics either. So, I've changed directions. I've gone back to the original C3 rear bar, and I'm looking at welding a bracket to the knuckles to attach the swaybar links. Here's the rough setup using the stock C3 link (which will be replaced with adjustable heim joints) and the C4 bracket to show the concept. A custom weld-on bracket will be used.

IM001212.jpg

With the sway bar slid as forward as possible (done after this particular picture was taken), the knuckle bracket would be welded to some significant mass of aluminum. Anybody see any issues with doing this (outside of me finally getting around to learning to weld aluminum)?

Mike, i'ts hard to tell if from the photo, but when modding my stock rear bar, I found that turning it over/upside down from the initial attempt, made the whole thing better, and from what I can see there, it looks as if you are in a similar situation....just a thought....:smash::cool:

as for welding aluminum, surely you will practice all to hell first, that shit is the most tricky of all pure metals to weld, so I"m told, and many of the 'aluminum' castings in cars are not really pure enough in the metal and so they tend to 'blow'....I not a welder, but am repeating comments my welder buddy has made over the years....
 
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Here is how I did it

I want to thank the forum for showing me that it was acceptable to heat and bend a hollow sway bar. Therefore, I was able to change the shape of my rear C4 24mm bar to fit my C3. I simply welded an aluminum plate under the mount and drilled out holes to mount to the C4 spindle. I really like how it turned out. I think it is plenty strong for spirited street driving.thum_12974b9c54be1dcf6.jpg
 
Duct Tape?

Better than welding the mount to the toe link!!
It is re-inforced with a vertical gusset on the back so it won't flex, should have noted that. It isn't going anywhere....
-CB
 
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