Broken sway bar

[Josh]

So I noticed the car pulling hard to the right when braking. Took a look and saw this. What would have caused this? Also is it worth fixing or just look for a new sway bar?

[Tillsy]

That doesn't even look like a stock sway bar - was it not properly rated for the flexibility required there?

[D Knight]

The problem is the sway bar is also being asked to act as a radius arm. Installing the LCA brace kit or going with Dave's new arms will help to allow the bar to focus on controlling body roll.


-D Knight-

[NightFlyer]

So I noticed the car pulling hard to the right when braking. Took a look and saw this. What would have caused this? Also is it worth fixing or just look for a new sway bar?

Lot's of possibilities as to what could have caused that - everything from improper mounting geometry to hitting something that exceeded the bar's specs to defective metal in the manufacturing process. Hard to say for sure (probably impossible) exactly what caused your failure.

Personally, I don't think that repairing would yield acceptable results, thus IMHO, it's new bar time, unfortunately....

[Delorean Industries]

Without seeing it first hand in this case I have seen this once before. It was from a massive impact with a cinder block according to the owner. But there was no impact marks on the bar. Just sheered off where it necks down.

[Nicholas R]

Could be just the perspective but that sway bar looks bigger than stock to me.

[Josh]

lol, its a stock sway bar, just galvanized.

The LCAs are fine, these are DPIs SS units.

I have been driving on some rough roads lately. I think it is compounded by the fact I overtorqued the sway bar bolts. I also did this several times as I was working on suspension alot over the last month or so.

[Bitsyncmaster]

lol, its a stock sway bar, just galvanized.

I wonder if the heat from the galvanizing upset the sway bar heat treating. Looking at the photo it does not look like the sway bar has the correct geometry.

[Nicholas R]

I wonder if the heat from the galvanizing upset the sway bar heat treating. Looking at the photo it does not look like the sway bar has the correct geometry.

I wondered the same thing. I deal with the concern of distortion and residual stress from hot dip galvanizing a lot at work.

Either way, if you knowingly overtorqued it, that's likely the cause. The end of the sway bar is just mild steel that is threaded; it's no where near as strong as normal hardware. Most mild steels, (ie ASTM A36) have a tensile strength of ~60,000psi. That's not even as high as the minimum requirements for a bolt to be a certified grade 2 (sae) bolt.

I suppose there is a very slim chance that the bars may have been heat treated or case hardened from the factory since it's constantly loaded, but the heat treatment would likely be lost during the galvanization. Still, given where it broke, it looks like the bar was over torqued.

[Bitsyncmaster]

Hot dipped the temp bath of molten zinc at a temperature of around 860 °F (460 °C).

That would defiantly upset any heat treating. Now we need to find out if the bar is heat treated.