The top of the shock absorber's piston rod is sensitive, and prone to damage from strain when installing an EDFC motor. This happens if the motor is screwed in by force. Avoid strain, tightening the motor and its core in turns.
Align the hexagon parts of the motor shaft and the set screw, and insert.
Holding the motor still with one hand, give its centre screw 3 full clockwise turns with a flat-blade screwdriver.
Gently screw in the motor casing until it halts. Turn the centre screw twice fully with the screwdriver. Gently screw in the motor casing again until it halts.
Fully tighten the motor at the prescribed torque. To check that its shaft functions smoothly, turn the core screw with the screwdriver: clockwise once, and once back.