ball joint failure is a very critical safety issue whether the car is a rolls royce or mercedes benz.

Surely the design can be called flawed but nearly 80% of the worlds car's use this design very effectively. The rest have it backwards - like the older W123 and the later W210 have the ball under compression - so even if the joint goes sloppy it remains in the shell.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)