........takes one to know one!
In my case the return springs around the cable at the hookends twisted and restricted the hooks from operating properly. ( wow, that was a moth full...)
So, leave the cable attached to the hooks, but slip the disk that the other end of the spring rests in out of its resting place, therefor taking the tention of the hooks which should move freely now when moving the hooks by hand and not by cable. ( are you still with me.....?)
Now, lubricate the hook-hinges and play with the length and position of the springs. I had to shorten one and straighten the other one out by supporting it with some tie-wire to have it sit perfectly straight and not binding the cable operation.
So, there, hope that will solve your problem....let me know please.
CHEERS !
WITT !