2004 Nissan Titan parking breaks

I went to replace rear breaks and removed rotor to see what the condition was with the parking breaks. I wanted to adjust them because when I try to engage them there is nothing. Truck will just roll if not in Park. Opened them up and there was nothing. No shoes, no springs , no cylinder to force pressure out. Nothin What should I do. Would this pass inspectionin Pa. I replaced the pads. I just bought it privatly.