Thanks for the advice everyone. The Midwest of US is not kind on the X5 due to the snow &
road salt this time of year. I was reluctant to pull the knuckle off, because I'm lazy, but I think it's unanimous that it's the best way to go from here. I will start with the impact on the remaining bolt at it's lowest setting. Been spraying penetrating lubricant on both of the bolts to ease final removals. I don't want to break another bolt. I'll let you know how it goes. Hopefully I can get some time this weekend.