TM  55-1730-201-12 on  the (2) piston rod  assembly  (14). Install   the   preformed (12).  Install  the  piston (14)  and  secure  with  retaining packing   (11)   on   the on  the  rod  assembly ring  (10). (3)   Lubricate   the   piston   and   rod   assembly   with hydraulic    oil,    MIL-0-6083,    and    install    in    the    ac- tuating   cylinder(l). (4)  Install (14). (5)   Install assembly   (6). (6)   Install assembly   (6). (7)  Install the   bushing   (9)   on   the   rod   assembly the   retaining   ring   (8)   in   the   sleeve the   lock   assembly   (7)   on   the   sleeve the   sleeve   assembly   (6)   over   the   rod assembly  (14)  and (8)   Install   the assembly  (6)  and actuating   cylinder   (1). actuating   cap   (3)   in   the   sleeve secure   with   the   two   bolts   (2), washers  (4),  and  nuts  (5). e.    Installation. (1)   Position   the   hydraulic   cylinder   assembly on   the   upper   structure   and   reservoir   bracket   and secure   with   the   two   pivot   pins   (19,   figure   1)   and cotter   pins. (2)   Connect   the   flexible   hose   (2,   figure   4)   to the   hydraulic   cylinder   assembly. (3)  Remove  the  support  from  the  upper  structure and   operate   hydraulic   pump.   Fill   reservoir   to   with- in   one   inch   of   filler   neck   with   hydraulic   oil, MIL-0-6083. Section V. UPPER STRUCTURE ASSEMBLY 38.  GENERAL. The   upper   structure   (figure   2)   consists   of   the work   platform,   stair   supports,   steps,   and   handrails. Height   variations   of   the   upper   structure   assembly are   controlled   by   the   extension   or   retraction   of   the hydraulic    cylinder    assembly. 39. UPPER STRUCTURE ASSEMBLY REMOVAL AND  INSTALLATION. a.   Removal. (1)   Remove (paragraph   37). (2)  Drain  the the   hydraulic   cylinder   assembly hydraulic   reservoir   (paragraph   35). (3)   Remove   the   two securing   the   handrails (10). bolts  (8,  figure  1)  and  nuts (7)   to   the   base   assembly (4)   Remove   the   eight   cotter   pins   and   four   pivot pins   (14)   securing   the   stair   supports   (22)   to   the base   assembly. (5)   Using   a   suitable   hoist,   lift   the   upper   struc- ture  assembly  (4)  from  the  base  assembly. b.    Installathn. (1)   Position   the   upper   structure   assembly   (4) on  the  base  assembly  (10)  and  secure  with  the  four pivot  pins  (14)  and  eight  cotter  pins. 14 (2)   Position   the   handrails   (7)   to   the   base   as- sembly  and  secure  with  the  two  bolts  (8)  and  nuts. (3)   Fill   the   hydraulic   reservoir   (paragraph   35). (4)   Install   the   hydraulic   cylinder   assembly (paragraph   37). 40.  PLATFORM  ASSEMBLY  AND  PLATFORM HANDRAILS. a.   Removal. (1)   Remove   the   two   pivot   pins   from   the   upper end  of  the  hydraulic  cylinder. (2)  Remove  the  eight  cotter  pins  and  four  pivot pins  (3,  figure  1)  securing  the  platform  assembly (23)  to  the  stair  supports  (22)  and  lift  the  platform assembly   from   the   supports. (3)   Lift   the   platform   handrails   (1)   from   the platform    assembly. b.   Cleaning,   Inspection,   and   Repair. (1)  Wash  all  parts  in  cleaning  solvent,  Federal Specification    P-D-680. (2)   Inspect   all   pivot   pins   for   excessive   wear. (3)   Inspect   the   handrails   for   cracks   and   exces- sive   looseness.   Weld   small   cracks. (4)   Inspect   the   platform   plate   for   surface   wear