[944s2cab]

Help! How do you separate the strut/shock from the spring? I've removed the whole assembly from the car and cannot find a way to unscrew the upper lock nut from the piston shaft. The center of the nut has a hex key opening. I have the right hex key and the right socket...but cannot get both into position to unlock the two. (I've seen the 'open ratchet' sets that allow for slipping a hex key through the center of the socket but none of the special sockets are large enough to go over the nut - about 22mm is required I believe and those sets only go up to 21mm). I've tried to grab the shaft carefully but securely but can't clamp down on it enough without damaging it. How is this done?