The Stovebolt Site Forums The Shop Area General Truck Talk RE-Tempering a Sway Bar????

Has anyone ever tried re-bending an anti-sway bar and had any success re-tempering it after words? I have now idea how you would determine the alloy of the bars, if you knew that you might be able to finagle a rough back yard heat treat.
There are a lot of bars out there that could be used if they could be reshaped a tad.
Denny Graham
Sandwich, IL

I'm going to play Devils advocate. Why not buy a bar bend it to shape and have it tempered. 300below.com does cold tempering for NASCAR and claims no dimensional loose. I'm thinking your going to have to heat the sway bar to bend it. Then heat it again to temper it. From what little I know, and I'm not metallurgist or engineer, your not going to do the metal any good. That and adding heat for tempering after you've bent it may not leave you with the shape you wanted.

I've talked with the folks at 300 Below and they were very helpful. They might even be able to tell you what you need for material.

Larry

I found a thread here I am not sure how good the info is but it was good reading. By the way Denny I am going into withdrawals waiting for some new webshot photos of what you are working on.

Just a bit of info, many sway bars from late model vehicles are hollow, rather than a solid bar. Not sure if that would actually make much difference, though.

Neilroy, Nice link good information. I wouldn't have suspected, it seems to fly in the face of what little I know, heat removes temper. I've got a sway bar I'll have to try it on, but not soon.

Larry

How about a spring shop, like Eaton Detroit Spring?
They have the equipment to do it, but do they have the know how? I think they should..

Grigg

Well, thar seems to be as many opinions out there as as there are fish in the sea. Just wanted to hear what you all have experienced and I’m sure this has crossed a lot of your minds at one time or another. My understanding has always been that they were made from an alloy and that they were tempered. Obviously they could be reshaped by heating but my personal feeling is that they would need to be heat treated after bending. Heating them would leave them in an annealed condition if they were simply left to cool down in still air. If they were quenched they would have been to hard and would need to be drawn back before using them.
However, I have read as many reports on various forums where they have been heated, bent and used with no problems for years. That really does go against my logic, but as they say, you can't argue with success. I still haven’t found a reliable source that could tell me what the alloy is, that would answer a whole bunch of questions.
Interesting subject, thanks for your opinions.

Neil, I one of those guys that is money dumb, and with the economy in shambles my retirement income is down more than I care to admit. But the good news is, I get to keep the house and truck! Haven’t been working on the truck much lately because of all that, I’ve been spending my buddy’s money, helping him get his ’50, 1/2 ton road worthy. Spent the winter learning about record players, I’m into radio collecting and restoration but never messed with the phonographs till this winter.

As a side note, I threw a question out about using a anti-sway bar on my 3/4 ton over at the VCCA and the general consensus is that “it would do no good on a leaf spring chassis” or “they are only effective with independent suspension” or “why would you want to do that with a 3/4 ton truck”, that last one I still can’t figure out. Seems to me that I’ve read a lot of reports from the Bolters here that are real satisfied with the results after installing an anti-sway bar on their straight axle AD’s.
Thanks all,
Denny Graham
Sandwich, IL

Won't work with leaf springs?? Then ask them this, if it won't work, then why did Chevrolet offer it as standard equipment on Panels, Suburbans, and 3/4 and 1 ton stake/platform trucks? Also, later model Duallies had them on the rear axle as well, as do most sfa 4x4 trucks.

I can tell you for a fact, that it really helps leaf spring trucks. Mine drives a lot better with one on the front. Plus I feel a lot better knowing if I have to make a quick lane change for some reason, that the truck just isn't going to lay over right there in the lane!

Joe

They even use really big ones on medium duty trucks with leaf springs.
Take a look under the front of a Chevy TopKick or Kodiak next time you see one.

Grigg

Gee Bill, do ya suppose that was the first thing that came to mind when I read that? Gene Snider is one of the most knowlage guys on the old Chevys that I've run into. His research came up with 1939 up for the front stabilizers stock from the factory on the Panels, Burbs and Cab Overs. They must have done somethin or GM wouldn't have wasted all that iron all those years.

Yeah, they are pretty common now days aren't they Grigg.

DG

Denny,

I am not sure what material GM uses but according to Hellwig's website, they use 4140 alloy steel, a very common carbon steel shaft material. There are lots of different heat treatments that can be done to 4140. A simple hardness check of one can tell you a lot of information about what kind of heat treatment process was used and the resulting yield strength of the bar. More important than the strength or harness of the 4140 is the actual bar diameter. Since the bar acts like a torsion spring, the spring rate varies with the bar radius raised to the 4th power.

Here is some specific information on the various heat treat properties of 4140 from MetalSuppliersOnline:

General Information

Principal Design Features

This is one of the chromium, molybdenum, manganese low alloy steels noted for toughness, good torsional strength and good fatigue strength.

Applications

4140 is used in a tremendous variety of applications, too numerous to mention here.

Machinability

Machinability of this alloy is good in the annealed condition. In the heat treated and quenched condition machining is best limited to finish grinding.

Forming

As with all the low alloy steels forming may be done by conventional methods with the alloy in the annealed condition. These alloys have good ductility, but are tougher than plain carbon steel and thus usually require more force, or pressure, for forming.

Welding

Weldable by all of the conventional methods. Note that welding with the alloy in the heat treated condition will affect the mechanical properties and a post weld heat treatment may be needed.

Heat Treatment

This alloy is hardened by heating to 1550 F and quenching in oil. It is best to normalize the alloy by heating at 1675 F for a long enough time to permit thorough heating, followed by air cooling, prior to the hardening treatment.

Forging

4140 may be forged at 2200 F down to 1700 F.

Hot Working

Hot working, if required, may be done in the range of 1900 F to 1500 F.

Cold Working

The alloy readily cold works in the annealed condition by conventional methods.

Annealing

Annealing is done at 1600 F followed by slow furnace cooling.

Aging

Not applicable to this alloy.

Tempering

Tempering temperatures range from 400 F to 1200 F depending upon the hardness level desired. The lower the tempering temperature the greater the hardness of the alloy. For example tempering at 600 F gives a tensile strength of 225 ksi while tempering at 1000 F will give 130 ksi.

Hardening

Hardens by cold working, or heating and quenching - also see "Heat Treatment" and "Tempering".

Thanks Kevin, I've worked with 4140 in our fabrication/machine shop many times, unfortunately in this case we don’t know whether the bars are 4140 or not. At one time many moons ago we did make torsion bars for midget racecars. We used 4140 for the torsion arms but the torsion bars were 5160 and we would turn the center section to different diameters to give a different spring rate. The subject of heat treat is a rather involved one and heat treat of alloys is best left to a qualified heat treat facility.
There is a good chance that the springs for your truck are 5160 or a similar alloy. But to get back to the stabilizer bars, they would almost have to be made from a high silicon spring steel like 5160 to allow each side of the suspension to work independently, the purpose of the bar is not to lock the two sides rigidly together but to tie them together within a limited range of independent movement. After thinking about this for a while, I don’t think that 4140 would be the best choice. It is a chromium, molybdenum, manganese low alloy steel and is noted for toughness, good tensional strength and good fatigue strength, which means that it is not really a very good spring. I’m afraid that a 4140 bar would give you a pretty rough ride over an uneven road.
Well I’ve bout beat this one to death and I think my mind is about made up, I’m goona go with one of the CPP anti-sway bar kits rather than try to modify one. They are reasonably priced and fit the original holes without having to drill new holes or modify the original parts in any way.
Denny Graham

Just a note here about the CPP bars. They are made by Addco. Addco is an aftermarket and OEM bar manufacturer. According to their web site they pioneered cold bending of sway bars.

Lonnie, where did you hear that Addco is the supplier of the CPP bars? They do not list CPP as one of their distributors.
Not exactly sure what they mean about pioneering the cold bending of sway bars. Toyota was a leader in the cold forging process and was a major contributor in developing the dies.
DG

Denny,

I don't know if they supply all of CPP's bars, although I would not doubt it.

The CPP front sway bar I bought for my 54 has a Addco sticker on it, as well as warranty card and product information from Addco in the packaging.

Lonnie

Lonnie, that’s good enough for me. I’ve sent a note off to ADDCO asking about their suppling bars to CPP. I would also like to know if their manufacturing facility is in the USA or if the product is made off shore and imported.
There has been some discussion on another forum where the CPP bars were referred to as “cheapo Chinese aftermarket units.” That may be a bad rap for a really decent part that is still made in the USA but we won’t know unless we hear it from the horse's mouth.
Thanks
Denny Graham
Sandwich, IL

Okey Dokey, here's the skinny on the AD front sway bars from CPP. I ordered one for my 1950 today and checked on the source. They buy them from another vendor who has them made for them by Addco. I haven't heard back from Addco yet whether they are made here in the states or off shore.
Denny Graham
Sandwich, IL

I'm afraid you'll need to do some fabricating when you get the bar Denny. Your frame is a bit wider than the 1/2 ton and that's what cpp will send you. You can check my pics out for how I did mine.
Another thought: why be concerned with bending the bar; just buy one that was made for the width of your frame. You might have some tweaking but seems to me that would be easier than bending.

Cpp doesn't carry sway bars to fit 3/4 ton ADs.

Now you tell me!!!! I ordered one last night right after supper. I tink ya got that backards Big, the 3600 frame is just under 4" narrower than the 3100, 25 1/2” vs 29 1/2” respectively. That has always baffled me why the 3/4-ton frame is narrower than the 1/2-ton. So I guess that means I'd have to deal with about 2" extra bar on each side? Dang it! Are the legs parallel or can they be bent in at the ends to compensate for the narrower frame?

I'll take a look at your link as soon as I get time, gotta go make supper now for my "big old wife".
DG

Isn't the front of a 3600 the same as a 3100? Only the rear is different.

What a minute Jim, I have looked at your album before come to think of it. You have a completely different truck than the Advance Design truck that I have. Yours is a modern IFS disc brake V8 automatic with bucket seats, AC, PS, tilt steering, mag wheels, in other words ya got a hot rod thar Big guy.
I’m stock as stock can be and the front bar is completely different for the AD.

Nope Lonnie, just looks the same,frames and axles are quite different.
Denny G

Denny:
You were talking about adding a sway bar to the rear not the front. Your right the frame on a 1/2 ton is about 11 inches wider than the 3/4. Don't let all that chrome and good looks confuse you; the ubolts etc. for the rear will fit unaversally so that won't be a problem for you. I drilled holes in the frame and bolted the bar up there. It works OK. I don't think you can bend the bars to fit. Check these pics...
http://s729.photobucket.com/albums/...current=SwaybarEndConnectDriversSide.jpg

Denny,

You made me go dig out my assembly manual; the 3100 and 3600 frames are the same from the front to just in front of the K-member.

Lonnie

Don't know where ya got that idea Big, I've been talking about the front bar all along, did I make a typo somewhere back there??

Lonnie, they might look the same but if you look on page 144 of the "Truck Data Book" the chart lists the width at the front at 29 1/4" for the 3100, 25 1/2" for the 3600, 25" for all of the larger trucks.
Rears are 47" for the 3100 and 36" for all the rest.

DG

Denny,

Is the "Truck Data Book" a GM publication?


I checked my assembly manual last night I remember the front of both frames being 25.5 inches. I will measure my 3100 frame tonight to make sure.

It was, and that would be the Salesman’s Truck Data Book. All of the vendors sell them, here is just one source and happens to be the vendor that I got mine from: http://www.classicparts.com/1949-Truck-Data-Book/productinfo/05-120/ .
It’s a bargain for $22.95 very well done reproduction of the original books and loaded with information, I quote from the Forward: “Models, capacities, dimensions, specifications. Optional equipment, tables, data and formulas are included to aid in the selection of the truck best suited to the operator’s needs”
I don’t think any serious Stovebolt pilot should be with out one, and you to can become an expert on Stovebolt statistics overnight.
Denny Graham
Sandwich, IL

I just measured the front of my 3100 frame. 25.5 inches.

Lonnie

And your in the same boat that I am Lonnie. The 1949 Salesmans data book is either wrong or they changed the frames after '49. I have a '50, 3600 and my buddy has a '50, 3100. I measured both frames and the mounting holes for the sway bar and they are both the same, i.e., 25 1/2". Now just how in the H#$$ are we supposed to become experts when we get bad information like this from GM.
So, to get back to the CPP anti-sway bar it doesn't look like there is going to be any problem after all.
Denny Graham
Sandwich, IL

When you're finished Denny take some pictures.

Denny, a limited amount of reshaping can be done by cold-bending with hydraulic jacks, chains, and leverage points. Unless you're doing a radical reshape, you probably won't have to do any heating. A 25-ton hydraulic press and some home-fabricated bending jigs just might be all you need.
Jerry

I threw in the towel Jerry, I just went ahead and sprung for the sway bar kit from CPP. The bar, bushings and brackets look very much like the original one, only real difference is in the links and attach point for the links. If I have time and if the angle of the bars work out I might just try to reproduce the articulating links that clamp to the I-beam like the later GM bars used.
I'll do that Jim, i.e., post a picture.
I never thought I’d get this much out of it, but it turned out to be an interesting discussion guys, thanks.
Denny Graham
Sandwich, IL

There are some differences in the after market bars. They stop short of the center of the axle where the originals mounted. They mount with a bracket that uses the front U-bolts. I suppose that the bar could be moved to the rear with new front mounting brackets and links could be fabricated to match the originals.

Mine fits very nice after I made new link brackets. With the mono springs the links did not line up properly.

Here are some pictures I was not takeing pictures of the sway bar so they do not show the mounting.

Thanks for the pics, I see what you mean. Looks like the hole center falls a couple inches short of the axle center-line. Well I'll just have to wait till I get it all here to see what I have to work with.
DG

Ok, here we go, consumer report on the Classic Performance Parts sway bar.
UPS dropped the CPP bar of today and I went straight to installing it. And indeed there is no way that it can be used as a replacement for the original GM bar, its just to short to use with the original style GM articulating links and the arms are not parallel which they would need to be for a bracket to be clamped onto the I-beam. So I can chalk off the idea of making it look exactly like the original GM sway bar.

The box says “CP-179, 1947-54 Chevy Truck Front Sway Bar, Stock Front End.” And yep, mine falls right smack dab in the middle there, it’s a 1950, but, it's a 3600, not a 3100.
So the first thing I had to do is take the link brackets out to the mill and open up the 1/2" holes to 9/16" so they would fit the 3/4-ton U-bolts. With that correction everything else just falls into place in a few minutes.

Now, I do have a couple more buts! But the top edge of the link bushing washer is right in line with the splash pans that are riveted to the frame. They sit about a fingers width below and on a hard bump or turn they are going to hit the pans on both sides. Next but! But the guy that made the bar must not have been talking with the guy that made the link brackets, because the centers are off by close to 1". This means the links are angled in on both sides. If the bar were spread 1" wider then the links would be straight up and down and the bushing would clear the outside of the splash pans.

Just to make sure this wasn’t unique to my truck I went over to my buddy’s to check the spacing on his 3100 and the only difference was just as I suspected, only the 1/2” U-bolts and all the other dimensions were the same.

All in all I’d give it about a B and with a little more effort on the brackets and attention to details like centerlines they could have a pretty accurate reproduction instead of a grade B aftermarket item.
Denny Graham
Sandwich, IL

A "B" is what I would also give it Denny. Now you might as well go all the way and add one to the back-end. The rear may be a little easier for you than me as I moved my rear springs in under the frame and that made me go above the differential.

Just noticed on a spare front axle I have, it came from a chevy P-30 chassis, 80's probably.
When it was removed the sway bar (about 1.25" diameter) was cut with an abrasive cutoff saw.. then it's been sitting outside for months..
Now that it has some rust I can clearly see about 1/8" around the edge that appears different from the core.

Not sure what that means, but for sure the bar is not the same throughout, some sort of treatment to the outside.

Grigg

Oh, I totally forgot to mention if it made a difference. Yep, not a bunch but I did take it out for 30 mile drive around as many curves and corners that I could find and it definitely makes a difference. It is a lot flatter than it was and I’m not getting that body roll that I was when I make a sudden lane change. I think it was worth the money and will handle a bit better in a panic situation; in other words, it’s a bit safer than it was before.
Denny Graham
Sandwich, IL