I have removed the 18mm nut to Detach the spring control arm from the rear axle (6a in diagram) however I am not able to remove the bolt it doesn't budge.
E55K SL500 E250X2 Smart44 Brabus Track car E450Cabriolet X350 Pick up
The bolt will be seized in the bush. Quite a few are. It's a complete pain. We soak them in penetrating fluid and work the bolt back and forth. Hit the bolt hard with a hammer.