a crucial moment the power unit has to be taken out the fitter has to open the eye of the connecting rod which encloses the crankshaft the nuts can only be loosened with a hydraulic bolt tensioning cylinder now pressure of up to 1,600 bars applied through hoses to ensure that all the bolts are loosened the four main bolts on the upper side of the power unit are also loosened with the help of the hydraulic system finally the power unit is free using nothing more than a pulley and their own strength the men maneuver the power unit