My passenger seat belt will retract but will not pull out to fit around passenger. I have opened up the back of the seat and tried adjusting the retract mechanisim. It will work one or two times then it retracts all the way and will not release. GM wants $230 for a new belt assembly. How is the old belt removed from the seat and the new belt installed. I have not purchased the belt from GM yet and thought I might be able to find one in a junk yard. Any help would be greatly appreciated.