A wrench for unthreading a well head flange from a pipe is provided. The wrench can include a pipe jaw for gripping the pipe, and a torque arm assembly for applying rotational force to the well head flange. The assembly can include a torque arm wherein one end of the torque arm can be pivotally attached to a bolt hole disposed through the well head flange. Extending a cylinder disposed between the assembly and to an opposing end of the torque arm can cause the torque arm contact and rotate the well head flange relative to the pipe.