I'm trying to replace the thrust arms on my dad e34 540i and everything went smooth until I tried to tighten up the bolt on the ball joint end. The ball joint kept spinning. Is there a trick to keep them from spinning to I can tighten it up. To me, it's such a stupid design from Lemforder thrust arms. On my e30, there's a slot on top of the balljoint for you to use the wrench and stop it from spinning. Please help.