TM 10-3930-669-34 CAUTION Do not damage rod surface.  Cylinder will leak if rod surface is damaged. (12) Remove  lock  nut  (15),  piston  (9),  and  head  (5) from rod (2).  Discard lock nut. NOTE Note location and position of packing,  expansion   ring,   wiper,   and seal prior to removal. (13) Remove preformed packing (16), expansion ring (17),   and   preformed   packing   (18)   from   piston (9).  Discard preformed packings and expansion ring. (14) Remove   backup   seal   (19),   preformed   packing (20),  rod  wiper  (21),  and  rod  packing  (22)  from head  (5).    Discard  seals,  wiper  and  preformed packing. 15-41