TM 10-3930-659-34 4-70. FORK/BOOM CYLINDER REPAIR (Con’t). 10. Install two new backup rings (10) and new preformed packing (11) on piston (3). 11. Apply a coat of petrolatum to preformed packing  (11) and two new backup rings (10). 12. Install spacer (13), two new wear rings (12), and new piston seal (14) on piston (3).  Ensure that gaps of wear ring are opposite each other. 13. Position retainer (4) on rod (6). 14. Apply a coat of petrolatum to inner and outer diameters of guide (9). 15. Position guide (9) on rod (6). 16. Install piston (3) on rod (6) until piston bottoms.  Back off piston until first key slot in piston alines with key slot of rod. TA708434 4-292