relates to a process for replacing a rotor blade bearing of a rotor blade of a wind energy turbine with rotor hub without a crane in that a rotor blade with a rotor blade bearing is dismantled from the rotor hub the one rotor blade bearing is replaced by another rotor blade bearing and the rotor blade with the other rotor blade bearing is mounted on the rotor hub the replacement in accordance with the invention is made possible without using an expensive mobile crane rotor blade bearings are exposed to high wear due to constant loading their replacement preferably takes place by the described apparatus without using a crane the invention is described in three figures using an exemplary embodiment in fig1 a three process steps of the dismantling or mounting of a rotor blade 10 are shown projected over each other positions x y z of rotor blade 10 are moved through in this sequence during the mounting of rotor blade 100 onto wind turbine 20 during the dismantling of rotor blade 10 the process steps are moved through in the reverse sequence z y x the mounting dismantling apparatus shown in fig1 a comprises obliquely tensioned guide cable 30 between tower head 21 of wind turbine 20 and ground 40 guide cable 30 is detachably fastened by one end to tower head 21 as shown in fig2 and 3 to rotor hub 190 or alternatively to two mounted rotor blades 11 12 and the other end of guide cable 30 is detachably anchored in ground 40 by a ground anchor not shown as an alternative to the ground anchor a heavy tractor or the like can be used guide cable 30 in.