TM 10-3930-669-34 15-6.  PIVOT CYLINDER REPAIR (CONT). (10) Position cylinder (1) in chain vise. CAUTION Keep rod straight and concentric in cylinder.  Do not allow piston to become wedged in cylinder or damage to cylinder or piston may occur. (11) Install  two  preformed  packings  (11)  and  plugs (10) in cylinder (1). (12) Install piston (9), rod (2), and head (5) in cylinder (1). (13) Push  head  (5)  back  in  cylinder  (1)  until  shear ring groove is exposed. (14) Install shear ring (6) in cylinder (1). WARNING Use  extreme  care  when  removing  or installing springs and retaining rings. Springs and retaining rings are under tension   and   can   act   as   projectiles when    released    suddenly.        Ensure proper    eye    protection    is    worn    to prevent injury to personnel. NOTE Shear   ring   will   prevent   head   from coming out of cylinder. (15) Pull rod (2) out of cylinder (1) until retaining ring groove of head (5) is exposed. (16) Install    spacer    (4)    and    retaining    ring    (3)    on cylinder (1) and head (5). (17) Remove pivot cylinder (1) from chain vise. NOTE Follow-on Maintenance: • Install pivot cylinder (TM 10-3930-669-20). END OF TASK 15-44