A method for screwing a nut for connecting a tube to an element by means of a screwing device, said tube extending through said nut, said device comprising a casing, a rotary end member able to cooperate with said nut, a motor and a transmission able to drive said end member and having an operating clearance, each of said casing and said end member having a lateral opening enabling, when they coincide, the passage of said tube into the end member, and thus defining an open position of the end member, said method comprising at least one screwing cycle comprising at least the following successive steps: - a step of placing, around the tube, the device in the open position, by making the tube pass into the lateral openings of the casing and of the end member; - a step of engaging the end member with the nut; - a step of tightening the nut; - a step of disengaging the end member from the nut; - a step of removing the device off the tube; characterised in that said method comprises, between the step of disengaging the end member from the nut and the step of removing the device off the tube, a re-indexing step during which said motor brings the end member back to said open position by driving it in rotation in the screwing direction, said device comprising a stop, said transmission being in rear abutment against said stop when said end member is in the open position after having been driven by said motor in the unscrewing direction, said method comprising a step of measuring in real-time at least one piece of information representative of the unscrewing torque, said method comprising a step (67, 67') of returning back in rear abutment successively comprising: - a sub-step (671, 671') of driving said motor in the screwing direction by a predetermined angle K; - a sub-step (672, 672') of driving said motor in the unscrewing direction until said piece of information representative of an unscrewing torque exceeds a predetermined threshold corresponding to abutment of the transmission against said stop, said end member being in said open position, said step (67, 67') of returning back in rear abutment being implemented upstream of the step of tightening or following the re-indexing step. said method comprising at least one screwing cycle comprising at least the following successive steps: - a step of placing, around the tube, the device in the open position, by making the tube pass into the lateral openings of the casing and of the end member; - a step of engaging the end member with the nut; - a step of tightening the nut; - a step of disengaging the end member from the nut; - a step of removing the device off the tube; - a step of placing, around the tube, the device in the open position, by making the tube pass into the lateral openings of the casing and of the end member; - a step of engaging the end member with the nut; - a step of tightening the nut; - a step of disengaging the end member from the nut; - a step of removing the device off the tube; characterised in that said method comprises, between the step of disengaging the end member from the nut and the step of removing the device off the tube, a re-indexing step during which said motor brings the end member back to said open position by driving it in rotation in the screwing direction, said device comprising a stop, said transmission being in rear abutment against said stop when said end member is in the open position after having been driven by said motor in the unscrewing direction, said method comprising a step of measuring in real-time at least one piece of information representative of the unscrewing torque, said method comprising a step (67, 67') of returning back in rear abutment successively comprising: - a sub-step (671, 671') of driving said motor in the screwing direction by a predetermined angle K; - a sub-step (672, 672') of driving said motor in the unscrewing direction until said piece of information representative of an unscrewing torque exceeds a predetermined threshold corresponding to abutment of the transmission against said stop, said end member being in said open position, - a sub-step (671, 671') of driving said motor in the screwing direction by a predetermined angle K; - a sub-step (672, 672') of driving said motor in the unscrewing direction until said piece of information representative of an unscrewing torque exceeds a predetermined threshold corresponding to abutment of the transmission against said stop, said end member being in said open position, said step (67, 67') of returning back in rear abutment being implemented upstream of the step of tightening or following the re-indexing step.