Despite what the FSM says, I feel Duke's method is safe, so long as common sense is applied.
Jackstands on level/hard/solid ground, and so forth.
Jackstands with a concave top {designed to receive an old-fashioned tube axle} fit perfectly to the arm here, while flat-topped one would not be as safe.
Just be very careful, and do not sue us.

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1986 300E 5-Speed 240k mi.