TM 10-3930-669-34 15-8.  MAST SECONDARY CYLINDER REPAIR (CONT). (5) Install wear ring (6) on rod (5). CAUTION Keep  rod  straight  and  concentric  in cylinder.  Do not allow rod to become wedged    in    cylinder    or    damage    to cylinder or rod may occur. (6) Install rod (5) in cylinder (1). (7) Install  preformed  packing  (3)  and  backup ring (4) on base (2). (8) Install base (2) in cylinder (1). (9) Remove mast secondary cylinder (1) from chain vise. NOTE Follow-on Maintenance: •    Install    mast    secondary    cylinder (Para 13-2). END OF TASK 15-54