Help with Simulate Physics and Animation on a tractor

Hello everyone,

I’m new in Unreal 4 and i’m having a real hard time to use physics and animation on a “tractor”. Here is a gif showing what is happening:

https://gfycat.com/DistinctDarlingGlowworm

I need to use physics in my game, since i’ll be lifting spheres with the tractor arms. But, at the same time I need to move the tractor arms. I’m applying movement direct into the bones of my tractor, and if i’m not using simulated physics, it works but I lose the physics simulations (wich is very important).

So, is there a way to make the arms of the tractor “freeze” and only move with some input? (using simulated physics)

Thank you.