Problems modifying unreal rigs in Maya and exporting back to Unreal

I bought a turret asset Autonomous Combat System in Characters - UE Marketplace from the marketplace and have been trying to modify it for my use. I had split the turret in 2 so the turret itself can move independently from the feet. The bones not in use I deleted and moved the new root bone to world center. However, when I import to unreal, although I had deleted bones pertaining to the lower portion, the overall position of the imported turret file did not change (Imports as though the lower portion of the turret is still there). Even though the bones are in a specific configuration in maya, the root bone seems to stretch (in unreal) to take the place of the lower turret. How can I fix this?

https://s7.postimg.org/myfsfzoe3/Maya_Modified.jpg
https://s7.postimg.org/myfsfzw3v/How_It_Appears_In_Unreal.jpg