Trying to attach omech to pivot and detach then simulate physics

Hello. I’m trying to attach a mech to a pivot point (Arrow component) and it works. But what doesn’t work is that when I try to simulatI physics i cant attach the mech. But then I tried to turn simulate physics on and off. Turning physics off before attaching and turning it back on when deattaching. But still I can’t attach the mesh… Any ideas?
Thanks.