80 series sway bar material type

[Rifleman]

It'll bend on both sides of that joint, and likely break the joint.

Yep, where he has heated it, that's annealed the steel and made it soft. At first it'll twist under load, then in short order the steel will begin to quickly work harder being twisted back and forth. Next, on one side or the other of that joint It'll break. If it were me, i would have cut the bar using a high speed cut off wheel thereby minimizing the heat effected zone. Next i would have had a machine shop milled the slot, tang and drill the hole to the size he needed. Doing it this way would have saved the factory heat treat.

 

[cody c]

Yep, where he has heated it, that's annealed the steel and made it soft. At first it'll twist under load, then in short order the steel will begin to quickly work harder being twisted back and forth. Next, on one side or the other of that joint It'll break. If it were me, i would have cut the bar using a high speed cut off wheel thereby minimizing the heat effected zone. Next i would have had a machine shop milled the slot, tang and drill the hole to the size he needed. Doing it this way would have saved the factory heat treat.

If your going to do that, throw a sleeve over top of the machined joint and run a pin through both, at least it will keep things in alignment and from jack knifing out

 

[Tank5]

Yep, where he has heated it, that's annealed the steel and made it soft. At first it'll twist under load, then in short order the steel will begin to quickly work harder being twisted back and forth. Next, on one side or the other of that joint It'll break. If it were me, i would have cut the bar using a high speed cut off wheel thereby minimizing the heat effected zone. Next i would have had a machine shop milled the slot, tang and drill the hole to the size he needed. Doing it this way would have saved the factory heat treat.

If your going to do that, throw a sleeve over top of the machined joint and run a pin through both, at least it will keep things in alignment and from jack knifing out

This is helpful. I have another sway bar, so I plan to try again and hope to get it right. I can have a machine shop cut a joint so it will fit together tightly. Is pinning the joint and sleeving really the best way?

Would welding it be better if I could match the material and have it tempered? I am going to talk to a machine shop tomorrow about it.

 

[YMT]

@Tank5 , I don't know what steel material was used. However, I have a couple spare sway bars, and will gladly donate one to your cause, if you choose to do a version of what @cody c suggested.

Maybe a dumb question, but with the narrowed axle, do you absolutely need a sway bar? I know this is Jeep relevant , but do you think you could run sans sway bar in the rear? Many Jeeps run without sway bars on highway all the time.

 

[cody c]

Would welding it be better if I could match the material and have it tempered? I am going to talk to a machine shop tomorrow about it.

I dunno if welding would, but I’d be dumb enough to try. I once had to burn the end of a leaf spring (military wrap that broke at the very end) and it held up for years, even though it’s supposed to fall apart )

I’ve Always learned more from being cautiously adventurous and analytical of failure than from being content with someone else’s prescription of imminent failure. Gotta trust your intuition once in a while, wherever that takes ya

When it comes to building stuff, you tend to try and make up with quantity for what you lack in quality, putting a longer sleeve over things, maybe some small rosette welds mid way while trying to avoid too much heat.

 

[Grandlooser]

Welding a sway bar I see as a fail almost any way you do it. At the very least eventually. If you are going this far with it, maybe see if you can find someone to spline both ends and use a splined collar to connect the two.

 

[Tank5]

@YMT Thanks for the offer I may take you up on the sway bar if my next version does not work out. I will share what the machine shop tells me after tomorrow.

@cody c I am similar in thought. I had read before I cut and welded the first version sway bar that it might not work and I figured I would try anyway to see if I could even keep it strait in the process. What I had not read before was that I couldn't temper my mild steel mig weld. I might mark the first sway bar version and run it just to see what happens. I figure I could mark the sway bar lengthwise across the welded section to monitor the twisting. I will likely do this just to see what happens.

I will of course make a version 2 in hopes it turns out good.

 

[Tank5]

@YMT there is a chance I wont need a sway bar. It is easier to weld the mounts for it now while I have the chassis stripoed than adding it later. I figure if it is not needed I can unbolt it and move on.

 

[Tank5]

Welding a sway bar I see as a fail almost any way you do it. At the very least eventually. If you are going this far with it, maybe see if you can find someone to spline both ends and use a splined collar to connect the two.

Cutting and then adding splines to both cut ends so they fit in a collar was a thought. I am going to ask about that tomorrow as well.

 

[Grandlooser]

It would also allow you to engineer
a pretty nifty quick disconnect if you wanted.

 

[cruisermatt]

I highly doubt you'll find out what material Toyota used for the sway bar.

I would run what you have and see how long it lasts. That's the kind of thing I do, try it and find out, learn for all of us. It's just a sway bar, what's the worst that happens?

 

[cody c]

So, not that I’m against splines, but I think they would have to cut splines in hard spring steel, and not roll them. If your going to be cutting splines cut in the shafts, and in some tube to go over them, I bet your into it for at least $50 a piece for 4 pieces if your doing both ends.

The cost makes it less attractive at a certain point.

You may as well look at junkyard torsion bars, and either find one short with splines ends and get the brackets at either end, or find one with hex ends and get some steel cut via plasma table or water jet. I’ve been contemplating doing this for my 80 for a little while and have most of a plan together for a pneumatic solenoid disconnect, but we’ll talk that in another thread

 

[MUDZLLA]

Since the FJ40 is half the weight of the 80, why worry about it?

 

[Rifleman]

If you are going this far with it, maybe see if you can find someone to spline both ends and use a splined collar to connect the two.

Cutting and then adding splines to both cut ends so they fit in a collar was a thought. I am going to ask about that tomorrow as well.

Cutting a keyway in that sway bar and installing a keyed sleeve you could do that. Cutting, or gear hobbing splines all the way around the OD of that bar is not going to happen. The reason for that is this, you have to be able to turn the sway bar to index it every so many degrees to cut each spline. With the body of that sway bar being an odd shape, and being so long it would be next to impossible to turn it 360 degrees while mounted in an indexer on a milling machine.

 

[Rifleman]

If your going to be cutting splines cut in the shafts, and in some tube to go over them, I bet your into it for at least $50 a piece for 4 pieces if your doing both ends.

I hate to tell you but at 50 bucks a piece you're not even close to what that job would cost you.

 

[Tank5]

I highly doubt you'll find out what material Toyota used for the sway bar.

I would run what you have and see how long it lasts. That's the kind of thing I do, try it and find out, learn for all of us. It's just a sway bar, what's the worst that happens?

I am building my sway bar setup around the one I have welded right now version 1. I was willing to just go for it, because as you pointed out if it fails I don't see it being catastrophic. I don't know but based of others more knowledgeable it seems like it will eventually fail. I am game for trying it out though.

I still want to build a better one that I am confident in, so I am trying to research version two options more thoroughly.

I expect your right that I may never learn what toyota's recipe is for the sway bar, so the sleeve concept in some form seems like the path forward. I will find out how cost prohibited the various options are tomorrow I hope.

 

[cruisermatt]

aren't you a ways away from having it it running and driving? I'd be holding off until then to worry about things like a sway bar, especially a second iteration of a rear sway bar, when you don't know if you'll even need it at all. If that makes sense? Long story short, go drive it

 

[Tank5]

Since the FJ40 is half the weight of the 80, why worry about it?

This 45 chassis originally came with arear sway bar and leafs. Before I started my build it was on 4" leafs, 37s and no sway bar. The body roll was crazy and wors with a load in the bed.

My build will still have 37s but will be on coils as low as I can keep it. The sway bar may not be needed but I would rather build it in to the design now than later.

 

[Tank5]

aren't you a ways away from having it it running and driving? I'd be holding off until then to worry about things like a sway bar, especially a second iteration of a rear sway bar, when you don't know if you'll even need it at all. If that makes sense? Long story short, go drive it

The sway bar may not be needed but I would rather build it in to the design now than later.

I am long way from driving but really plan to have it driving by August. The short answer is I am stalled on some other aspects of the build, so I am trying to get some small things done while I wait.

 

[cruisermatt]

The sway bar may not be needed but I would rather build it in to the design now than later.

I am long way from driving but really plan to have it driving by August. The short answer is I am stalled on some other aspects of the build, so I am trying to get some small things done while I wait.

Spend the money for custom valved shocks.
I do want to see your welded sway bar in action though.