The present invention concerning of a device for mounting or dismantling, replacement and maintenance of a can-combustor of a gas turbine engine including an assembly tool or assembly tool with additional frame having at least one lifting beam, at least one linear driver, wheels, at least one eccentric rolling hook for fixation of the gas turbine housing, optionally spacers for building the interface to the can-combustor, adapters, lifting points for the main crane. The eccentric rolling hook is connected to the gas turbine housing by giving in axial or quasi-axial direction a force for mounting or dismantling the can-combustor from the gas turbine housing.