Hi need help, iv managed to disconnect high presaure fuel pump and get a new one, however on trying to reconnect the new one when im tighthening the bolt the metal spindle/motor is also turning, how do i stop the from happening? As it wont tighten 

 

Pleasssssse help

Hi....welcome to the Forum

Without seeing which type of pulley attached to it I couldn't say if there is any slots in there that you can put a bar through to lock the assembly to tighten the nut.
As it is on a taper by the look of it it won't take much to tighten down.

Let us know how you get on with it