[staleg]

Yes, I know this have been discussed in earlier post. I just want to share my practical, newly earned experience...
Today I was going to fit a wrecking yard sway bar to my hot rod. The sway bar was from a Volvo 240 series, solid steel, 19,5 mm in diameter and app 2,5" too narrow, so I wanted to stretch out the bends on each side with app 1,75". Not very much, in other words.

I've always thought cold bending would be the best to be sure the metal not would change.

At my job we have a manual operated hydraulic press I used. I bent a little at the time, to ensure I didn't bent it too much. First side went well. On the other side the bar suddenly snapped off!

A "bang" and there it was in two pieces, 19mm straight off!

Luckily i had welding glows on (I held on one of the ends while I bent it) and the pieces didn't fly around. And I don't think there was any loose, small fragments either.
Why did this happen? Was the sway bar forged? And if so, does that mean I just can get another one and warm bend it instead?

[powerrodsmike]

At the point where it broke, was there evidence of a crack that had already been there?

Rust and dirt stains partway into the mating surfaces of the section that broke apart is the giveaway.


Forged parts usually have what looks like a mold parting line, but thicker.

Although I read the previous discussion, it seems like unless there was a previous crack, that swaybar might have been hardened in some way.

Volvo does things differently than most other car manufacturers...I mean that in a good way.


Later, mikey

[staleg]

Unfortunately I left the broken piece at work, but I will take a photo and post it on monday. The brekage surface looked very clean. No rust, traces of previous cracks or "dirty sports" in the metal etc.

Since I'm working in a chain factory, there are people at my job with good knowlegde in steel types, hardening, etc. I will discuss it with them.
I will also check this out on the Swedish hot rod discussion board. Maybe some of them have used Volvo sway bars (Swedish hotrodders use lots of other Volvo parts) and know what's the correct way (or if there are a correct way) to bend them.

After all I'm glad the thing snapped off. The other arm, that I bent first and that did not snap off, is probably weakened, since I must have been very close to the brakiong point when I bent that one too.

[aosborn]

Sway bars or anti-roll bars are indeed heat treated. They are very typically made of the same material and are heat treated like coil springs. They have to be heat treated to obtain the characteristics to perform the function they were designed for.