Road salt. It’s great at melting ice and corroding the stability right out of your ball joints.
“Mazda says salted roads during the winter can can cause saltwater to enter the ball joint and corrode the parts. The corrosion can cause the ball joint in the fitting to loosen and result in a rattle from the area of the ball joint and lower control arm. Enough corrosion and the ball joint can separate from the lower control arm.”
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