So there I was disconnecting the P-brake cable from the little hook on the driver's side rear caliper so that I could remove the caliper and pull my rear disc off. But I ran into something not covered in the Haynes manual

The hook that the cable slips over is connected to the caliper via a hinged arm that is held in position/tension by the tension of a spring. The center of that spring fits over, what I can best describe as, a protruding bolt head (better name? ) On the passenger side, this bolt would not move, i.e., it was frozen in position. In fact, I used it as leverage to move the arm forwards (towards the front of the car) in order to put some slack in the P-brake cable to get it off the hook. On the driver's side, however, it would rotate with pressure from my ratchet. If I rotated it counter-clockwise, the accordion-like portion of the P-brake cable (better name? ) would shorten; if I "tightened" it, it would increase the tension on the P-brake cable and stretch the accordion section.

My question is: should that "bolt head" rotate at all and if so, how do you adjust it to the right position?

Thanks to any/all who can decipher/answer my question.

Cheers