broken torsion bar? what to replace with and how fun is it to do?

2 Darts said

Thanks for the photos, guys. I didn't realize that the metal used in a torsion bar was so porous. Now I understand: 1. Why the paint on them is so thick. 2. Why every text I've read about removal says don't nick them but if you do, get the rust off the bar and repaint.

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What you are seeing is not porosity in the material, it is what I would call a fairly typical rapid fatigue failure. What you are actually seeing is the grain structure of the steel as the crack propagated very quickly, it is most likely a trans granular fracture where the crack goes through grains as opposed to around them. The reason you dress and coat any damage to the surface is that it creates a stress riser and an area for corrosion to attack. Smoothing it out and re-coating lowers the effect of the stress risers and the coating protects it. Most suspension components such as springs and t-bars are coated with with a soft coating that is designed to absorb the energy of an impact from road gravel, some springs mostly rears have a double layer of coating that can be over 200 microns thick for this purpose. If anyone is curious I am a metallurgist with several years of work on fatigue failures and corrosion testing and failure analysis of of corroded parts automotive suspension components, however; I did not stay at a holiday inn last light so YMMV.

I had one go on my car years back in the parking lot of my apartment, sounded like a shot gun blast and as the neighborhood was less than ideal I assumed it was as such. Came home from work the next day to the lean.