Axially expandable spacers (51, 53) are insertable between a nut (20), on a bolt (19) to be tensioned, and a face (F) on a component (C) and have ramp faces (52, 54) to take up the space as the bolt (19) is tensioned by an hydraulic tensioner (25), where the puller bar (35) is engaged with an extension (121) on the nut (120). A segmented collar (60) has radially movable segments (61) to allow quick engagement/release between the puller bar (35) and the end of the bolt (19) on the nut (120).