TM  9-2350-238-10 OPERATING  CRANE–CONTINUED OPERATION    PRECAUTIONS–CONTINUED 2 3 4 5 6 7 Any   kinks,   crushed   sections,   or broken   strands   are   potential weak   points   and   can   cause   wire rope   failure.   Frayed,   kinked, worn,   or   corroded   ropes   must be   replaced.   Rope   is   unsafe   if three   broken   wires   are   found   in one   strand   of   6   x   7   rope,   six broken  wires  in  one  strand  of  6 x  19  rope,  or  nine  broken  wires in   one   strand   of   6   x   37   rope. Observe   wire   ropes   when   winding   onto winches   for   proper   winding;   avoid   kink- ing   wire   ropes.   Inspect   wire   ropes   for frayed,   damaged,   or   broken   strands,   Use level   wind   on   tow   winch   wire   rope   for proper   Iayup. Observe   boom   cylinders   for   smoothness and   ease   of   operation. Observe   boom   drop   rate   (distance   boom drops   when   loaded   and   boom   cylinder control   valve   lever   is   in   center   position). Boom   will   gradually   drop   if   left   elevated with   a   hanging   load.   When   hydraulic   oil is   hot   from   recovery   operations,   the boom   drop   rate   should   not   exceed   1/2 in.   (1.3   cm)   per   minute   with   a   10,000 lb.   (4,536   kg)   load;   1   in.   (2.5   cm)   per minute   with   a   20,000   lb   (9,080   kg)   load; or  2  in.  (5.1  cm)  per  minute  with  a 30,000   lb   (13,620   kg)   load. Observe   boom   winch,   tow   winch,   and traversing   brakes   for   smooth   and   effi- cient   operation.   They   should   not   chatter or   slip. Observe   all   hydraulic   lines,   hoses,   and connections   for   oil   leaks.   Tighten   all loose   connections   after   relieving   all hydraulic    pressure. Listen  for  any  unusual  noises  or  indica- tions   of   malfunctions   in   winches,   slip ring,   hydraulic   valves,   and   traversing   unit 8 9 10 11 12 Release   and   apply   tow   winch   and   boom winch   control   handles   slowly.   Control handle  IS  spring-loaded   and   will   return   to neutral   position   when   released,   auto- matically   applying   winch   brake   which will   stop   unit   with   a   jerk. Make   sure   that   spade   is   firmly   emplaced and   suspension   is   locked   when   lifting   or recovering   heavy   loads. Refer   to   FM   20-22   for   vehicle   recovery techniques. Apply   and   release   pressure   on   load   slow- ly   to   decrease   possibility   of   damage   to load   or   equipment, Wire  rope  life  will  be  increased  by  lubricating wire  rope  at  regular  intervals  (appx  G)  and winding  wire  rope  tightly  and  evenly  on  winch drum. HOISTING   AND   TOW   WINCHING   LOAD RATING   CAPACITIES   INSTRUCTION   PLATE Hoisting   and   tow   winching   load   rating capacities   instruction   plate   (view   C,   page 2-75)   indicates   safe   operating   capacities   of boom   in   relation   to   weight   of   load   being lifted,   necessary   boom   elevation,   areas   where boom   may   be   located   while   supporting   load, and   whether   spade   is   emplaced   or   retracted. For   maximum   capacity,   vehicle   must   be   on level   ground,   suspension   locked,   and   load directly   under   boom   tip.   White   areas   on   in- struction   plate   show   where   boom   must   be positioned   with   different   load   conditions,   In all   cases,   boom   placement   must   be   kept within   white   areas   when   hoisting   a   load weighing   between   15,000   and   30,000   lb (6,810   and   13,620   kg).   When   hoisting   a   load up   to   15,000   lb   (6,810   kg),   operation   in shaded   area   is   permissible.   Information   cover- ing   maximum   tow   winching   and   hoisting capacities   with   spade   emplaced   (view   A, page  2-74)  is  shown  on  left  hand  side  of plate.   Information   covering   maximum capacities   with   spade   retracted   (view   B,   page 2-74)   are   shown   on   right   hand   side   of   plate. Information   concerning   center   of   load   and vehicle   clearance   is   presented   in   center   circle. Change   3 2-73