[COBALT]

Not necessarily. To really guage how bad of shape your trailing arms are in you'll have to remove them. Mine had cracks, some serious rust, and some places where the plates were comming loose.

After removing them I realized that the cracks weren't serious, and the rust was all surface. I scrubbed them down really well with a wire brush, and had a weld shop patch them including the reinforcement plates. They were as good as new with some new bushings, and new U-bolts for the rear axle.