I was sent the wrong rollers - nice try by a vendor. On my 73 Swinger ... I need the nylon roller (or assembly) that rides in the rearmost track - sits at a 45 and the roller is gone leaving the stud with the 3/8" or so steel ball - know what I mean ? Appears to me the roller itself may not be replaceable but may need the assembly ? Anybody got a diagram for reference ? Don't even mention R/T Specialties - not an option for me. Thanks for the help.