TM 10-3930-643-34 FRAME  AND  TOWING  ATTACHMENTS  MAINTENANCE.  (cont) Frame Hinge Pin and Frame Assembly. (Sheet 3 of 13) 10-2. ADJUSTMENT During shafts NOTE adjustment,  lock  plates  on must be kept from moving by frame stop blocks and spacers. 10. Center hinge alinement. Using feeler gage, measure at points A. The front frame tongues should be centered between rear frame ears so that the dimensions at points A are the same. 11. Using feeler gage, measure at points B. The dimensions at points B must be the same. Dimensions will not necessarily be the same as the point A measurements. NOTE Dimensions at points A and B must be spaced so that no part of the front  frame tongues comes  in contact with the rear frame ears. 12. Using  a  15/16"  socket  and  socket wrench  handle,  remove  two  bolts  (1), washers (2) and retainer plate (3) from lower hitch. 13. Using a 3-1/16" socket and socket wrench handle, remove nut (4). 14. Using a 15/16" socket and socket wrench handle, remove two bolts (5), washers (6) and retainer plate (7) from upper hitch. 15. Using  a  3-1/16"  socket  and  socket wrench  handle,  adjust  points  A  and B clearance of front and rear frame. If front frame tongues are too high, loosen nut (8). If front frame tongues are too low, tighten nut (8), refer to step (10 and 11) for proper dimensions. Go to sheet 4 10-8