TM10-3930-660-34 16-12.3.  OUTER BOOM - REPLACE/REPAIR (Cont’d) NOTE In  step  2f,  release  hydraulic  joystick  immediately  after boom     hoist     cylinder     (8)     being     removed     has     fully retracted.  If joystick is allowed to remain open, the other cylinder (8) will start to retract, putting extreme stress on lifting equipment and boom. f. Start  engine  and  run  at  full  throttle.    Fully retract boom hoist cylinder (8).  Cylinder (8) will retract very slowly.  Stop engine. g. Carefully    lower    cylinder    (8)    onto    board placed across vehicle deck so hydraulic line on cylinder (7) is not damaged. h. Repeat    steps    2d    through    2g    for    other cylinder (8). 3. PLACE JACKSTAND OR SUPPORT ON FRONT OF VEHICLE DECK. ADJUST SUPPORT  SO  THAT  OUTER  BOOM  (3)  WILL BE LEVEL WHEN LOWERED. 4. CAREFULLY LOWER OUTER BOOM (3) WITH HOIST  AND  SLING  UNTIL  FRONT  OF  BOOM (3) IS ON JACKSTAND OR SUPPORT. 5. REMOVE  OUTER  BOOM  (3)  FROM  VEHICLE FRAME. NOTE Center  of   gravity   for   outer   boom   (4)   is   approximately 92.5 inches from front flange of outer boom (3). CAUTION To  prevent  damage  to  lines  (4)  during  step  5a,  place wood  boards  between  underside  of  outer  boom  (3)  and slings. 16-83