TM 5-3895-374-24-2 DISASSEMBLY 1. Mark  head  and  casing  before  disassembly  to  insure proper  reassembly.    The  idler  pin,  which  is  offset  in pump   head,   must   be   positioned   toward   and   equal distance between port connections to allow for proper flow of liquid through pump. Remove  head  from  pump.    Do  not  allow  idler  to  fall from idler pin.  Tilt top of head back when removing to prevent this.  Avoid damaging head gasket.  If pump is furnished with pressure relief valve, it need not be removed   from   head   or   disassembled   at   this   point. Refer to Pressure Relief Valve Instructions, page 11. If pump has jacketed head plate, it will separate from head when it is removed.  The gasket between head and jacket head plate must be totally removed.  Use new gasket when assembling pump. 2. Remove idler and bushing assembly. 3. Insert   length   of   hardwood   or    brass    through    port opening    between    rotor    teeth    to    keep    shaft    from turning.      Bend   up   tang   of   lockwasher   and   with   a spanner wrench remove locknut and lockwasher from shaft. 4. Tap shaft forward approximately 1/2 inch and remove pair   of   half   round   rings   under   inner   spacer   collar. There is no pair  of  half  round  rigs  on  H  and  HL  size pumps. 5. Carefully  remove  rotor  and  shaft  to  avoid  damaging bracket bushing. 6. Mechanical  Seal  (Type  9):  If  the  mechanical  seal  in your pump ever fails, it can easily be replaced with a new  seal.    There  are  two  basic  parts  to  this  seal. They   are   the   rotary   member   and   seal   seat   (see Figure  6).    To  remove  mechanical  seal  loosen  set screws holding rotary member on the shaft.  Remove rotary  member  from  shaft  and  stationary  seal   seat from bracket. Viking furnishes a number of  heavy-duty  pumps  with special mechanical seals installed in the packing end of the pump. These special  seals  are  not  discussed  in  TSM142.1. Information   is   available   by   contacting   the   factory. When requesting special seal information, be sure to give pump model number and serial number. 7. Loosen  setscrews.    Two  for  H  and  HL  size  pumps, four for all other sizes.  With spanner wrench remove both  end  caps  and  lip  seals.    Remove  ball  bearing and spacer collars.  Refer to Figure 5, page 4. 8. Examine seal chamber lip seal and remove if it shows wear or damage.  Lip seal must be removed if bracket bushing needs to be replaced.  (Cataloged pump has a viton lip seal.) 9. Clean  all  parts  thoroughly  and  examine  for  wear  or damage.    Check  lip  seals,  ball  bearing,  bushing  and idler  pin  and  replace  if  necessary.    Check  all  other parts for nicks, burrs,  excessive wear and replace  if necessary. Wash  bearings  in  clean  solvent.    Blow  out  bearings with  compressed  air.    Do  not  allow  bearings  to  spin; turn   them   slowly   by   hand.      Spinning   bearings   will damage   race   and   balls.      Make   sure   bearings   are clean,    then    lubricate    with    nondetergent    SAE    30 weight oil and check for roughness.  Roughness can be determined by turning outer race by hand. Be  sure  shaft  is  free  from  nicks,  burrs  and  foreign particles that might damage bracket bushing. Scratches  on  shaft  in  seal  area  will  provide  leakage paths under mechanical seal. 10. Casing  can  be  checked  for  wear  or  damage  while mounted on bracket. page 3-1217