TM 5-3895-374-24-2 VIKING PUMPS DISASSEMBLY CONTINUED (3) Remove  the  idler  and  bushing  assembly  from  the  pin. Inspect  for  signs  of  excessive  pin,  head,  idler  and/or bushing  wear.    Replace  any  worn  parts  Note  the  pin grease groove position.  If applicable, prior to removing. (4) Remove the packing gland. (5) If  you  have  a  mechanical  seal  pump,  remove  the  end cap and the mechanical seal is exposed. (6) Remove  the  mechanical  seal  by  sliding  off  the  end  of the   shaft.      Loosen   the   set   screws   In   the   set   collar through the connection provided and remove it. (7) Carefully  remove  the  rotor  and  shaft  from  the  pump. Avoid   damaging   the   casing   or   rotor   bearing   sleeve bushing. (8) If the casing, rotor  bearing  sleeve  bushing  and/or  rotor show  signs  of  excessive  scouring  or  wear  they  should be replaced. (9) Remove the packing and press the rotor bearing sleeve bushing out through the stuffing box area.  Note that the rotor  bearing  sleeve  for  the  Q,  M,  N  and  R  pumps  Is bolted  to  the  casing  as  a  sub-assembly.    This  can  be removed to facilitate easier handling if the bushing must be replaced.  Mark its position prior to removing. REASSEMBLY NOTE Should    it    be    necessary    to    install    new carbon bushings.  extreme care should be taken to prevent the bushings from fracturing.  It is a brittle material and easily cracked.    If  cracked,  these  bushings  will quickly     disintegrate.          An     arbor     press should be used to install carbon bushings. Be sure the bushing is started straight and do  not  stop  the  pressing  operation   until the    bushing    is    in    the    proper    position. Starting and stopping this operation invariably results in bearing failure. Carbon    bushings    for    high    temperature systems are supplied with extra interference  fits  and  must  be  Installed  by an  arbor  press  after  heating  the   bearing bracket   or   idler   to   450°F.      Check   the bushing for cracks after installation. (1) Press   the   bearing   housing   bushing   into   place   and check  the  after  press  fit  size  to  ensure  clearance  (as specified  in  item  9)  exists  between  the  bushing  and shaft.    Lubricate  prior  to  startup  For  Q.,  M,  N  and  R pump     models     the     rotor     bearing     sleeve     can     be reassembled on to the casing. (2) Remove  all  burrs  and  rough  surfaces  from  the  rotor and shaft and assemble in the casing.  Start the shaft through the casing or rotor bearing sleeve bushing and slowly  turning  the  rotor,  push  it  into  the  casing  as  far as it will go. (3) Press   the   idler   bushing   into   the   idler   and   ensure clearance  (as  specified  in  item  9)  exists  between  the bushing  and  pin.    Replace  the  idler  disc  if  one  was originally supplied.  Replace the Idler pin, if necessary, positioning     the     grease     groove     as     noted     In     the disassembly.  Place the idler assembly onto the  head and lubricate the bushing to pin area prior to start up. (4) Place   the   head   gaskets   on   the   head.      The   proper amount   of   gaskets   should   be   used   to   provide   the necessary  end  clearance  within  the  pump  so  It  turns freely with no appreciable end play. (5) The  head  can  now  be  assembled  on  the  pump.    Tilt the  top  of  the  head  away  from  the  pump  slightly  until the  crescent  enters  the  Inside  diameter  of  the  rotor and  rotate  the  idler  until  its  teeth  mesh  with  the  rotor teeth.  Do not damage the head gaskets.  Check that the   head   and   casing   position   markings   are   aligned Tighten  the  head  capscrew  or  nuts  evenly  and  then check the end clearance.  If the pump shaft cannot be rotated, more gaskets must be added.  If, however, the pump  has  any  noticeable  end  play,  remove  enough gaskets so the pump has no appreciable end play but still turns freely. (6) Pack  the  pump.    It  is  good  practice  to  install  a  set  of new  packing.    A  packing  suitable  for  the  liquid  being pumped should be  used.    If  the  pump  has  a  lantern  ring  it  must  be located  below  the  grease  fitting  or  flushing  connection. The     grease     fitting     may     be     removed     to     facilitate positioning  of  the  lantern  ring.    Cut  the   packing   into individual   rings   that   wrap   exactly   around   the   shaft. Install and seat each ring  one  at  a  time  staggering  the ring   joints   from   one   side   of   the   shaft   to   the   other. Lubricate  the  packing  rings  with  oil,  grease  or  graphite to aid In assembly.  A length of pipe or tubing will help in seating the packing rings. (7) Install  the  packing  gland  and  nuts.    The  gland  must enter the stuffing box at least one-eighth of an Inch after tightening  the  packing  gland  nuts  Be  sure  the  packing does not wedge between the stuffing box and the gland, as this may split the stuffing box. (8) Install the mechanical seal:  Place the set collar on the shaft   and   tighten   setscrews.      The   seal   is   simple   to Install and good performance will result if care is taken in its installation. NOTE Never touch the sealing faces with anything except the fingers or a clean cloth.  Spread a   film   of   lubricating   oil   on   the   inside diameter   of   the   synthetic   rubber   bellows Check the end of the pump shaft for sharp burrs    or    edges    which    might    cut    the bellows.  Slide the seal rotary member over the shaft and up against the setcollar.  The spring  washer  and  spring  must  be  put  on the  shaft  first  and  in  that  order.    Coat  the synthetic  rubber  seal  seat  with  lubricating oil and push the seal seat into the end cap Put  the  end  cap  gasket  on  the  end  of  the casing.    Slide  end  cap  over  the  shaft  and flush  both  the  seal  seat  and  carbon  wear ring in the seal rotary member with oil Push the end cap up until the mating surfaces of the  seal  meet.    Install  the  capscrews  then tighten evenly. (9) Recommended minimum bushing clearances: AREA AREA Idler Bushing Casing Bushing Pump Model to Pin to Shaft INCHES INCHES G .0015 .0015 H & HX4 .002 .002 J-K-KK .0025 .003 L   -   LO   - LL .003 .003 Q & M .0035 .0035 N .0035 .0035 R Consult Factory NOTE The after press fit value is the final size for carbon   bushings.      No   sizing   should   be required. Page 3 - 1199