Remove the parts from the Seat Back Assemblies and deburr all the holes.
Dimple the holes in the F-637A Seat Back and machine countersink the corresponding holes in the F-637B Angles for the four flush rivets.
Prime the parts, then reassemble the Left and Right Seat Back Assemblies. Rivet them using the rivets called-out in Figure 1.
Place the Left and Right Seat Back Assemblies into position on the F-10103A Lower Seat Hinge Halves.
Locate the two hinge pins set aside on Page 33-2, Step 5, and cut them both in half. Make a 90° bend in all four pins 5/8" from one end. Grind the other end to a dull point.
Secure both Seat Back Assemblies with the four hinge pins.
