My concern is that anytime a washer is being bowed in - the spread of force is not even, This happens when a weaker washer is used. a 10.9 grade wont do this. It will retain its shape and be in proper tension under that nut. Specially on a W124 - as the design of the suspension is a bit faulty, that balljoint is under a constant pulling (separation) force from the spring on the control arm.

Just keep an eye on this - replace it with a 10.9 washer from an autoparts store if you find it misshaped further.

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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)