(a)  Remove  item  1  through  12  as  shown  on figure   14-11. (3)  Inspect  all  drive  assembly  splines  and  pin- on   teeth   for   nicks   and   burrs. (4)  Test  field  coils  for  insulation  breakdown with  megger  connected  between  frame  and  one  coil terminal.  Minimum  resistance  reading  permissible is  one  megohm. Replace   starter   assembly   if   coil   is defective. (b)  Lift  packing  (23)  and  knock  out  pin  (13). Remove  cover  (14). (c)  Disassemble  the  remaining  parts  in accordance  with  index  numbers  16  through  29. (2)  Disassemble  frame  and  field  coil  assembly as   illustrated   in   figure   14-12. (5)  Inspect  coil  terminal  lugs  for  damaged threads. (6)  Test  armature  for  grounds  with  a  test  light. Touch  a  test  light  probe  to  the  armature  core  and   the other   probe   to   a   commutator   bar   riser.   If   test   light glows,   armature   is   grounded.   Repeat   test   for   all commutator   bars. (3)   Disassemble   solenoid   assembly   as   illustra- ted  in  figure  14-13. 14-28.   Cleaning   and   Inspection. a.  Cleaning. (7)   Test   armature   for   short   circuits   using   a growler. (1)  Blow  out  all  dirt  from  inside  field  frame and  wipe  interior  with  a  clean  cloth. (8)  Check  brushes  for  excessive  wear. CAUTION 14-29.   Repair. Do   not   submerge   armature,   field coils,   solenoid   or   clutch   drive   in solvent. a.  Pinion  Housing  and  Commutator  End  Head. (1)   Smooth   minor   scratches,   burrs,   and   dents on  machined  surfaces  using  a  fine  mill  file. (2)  Clean  field  coils  and  frame  thoroughly  with a  cloth  dampened  with  cleaning  solvent  Federal Specification    P-D-680. Be  careful  not  to  damage protective   insulation   and   fungus   coating.   Dry   thor- oughly   with   compressed   air. (2)  Repair  damaged  threads. (3)  Smooth  minor  rough  spots,  score  marks, and   scratches   from   inside   bore   of   bronze   bearing using  a  fine  stone  or  crocus  cloth  dipped  in  cleaning solvent,   Federal   Specification   P-D-680. (3)  Remove  loose  particles  from  armature  with compressed  air  and  wipe  with  a  clean  cloth  dampened with   cleaning   solvent. Clean   commutator   lightly with  No.  00  sandpaper  and  remove  all  traces  of  dust with   low-pressure   compressed   air. b.   Brush   Holder   Assembly.   Replace   a   defective brush   holder   assembly. c.   Armature. — (4)  Clean  brush  holders  and  springs  with  a brush   and   cleaning   solvent,   Federal   Specification P-D-680,   and   dry   them   thoroughly   with   compressed air.   Clean   insulation   and   plate   with   a   clean   cloth dampened  with  cleaning  solvent  and  dry  with  com- pressed  air. (1)  Resurface  commutator  removing  no  more than  0.005  inch  during  any  one  cut  and  no  more  than 0.002  inch  on  final  cut.  Check  that  final  diameter  of commutator   is   not   less   than   1.6470   inches. (2)   If   commutator   diameter   is   satisfactory, undercut  mica  to  a  depth  of  0.025  to  0.032  inch  below commutator    surface. (5)  Clean  solenoid  relay  assembly  parts  with  a clean   cloth   dampened   with   cleaning   solvent,   Federal Specification   P-D-680,   and   dry   with   low-pressure compressed   air. NOTE (6)  Clean  brushes  with  a  clean,  dry  cloth  only. Do  not  permit  cleaning  solvent  to  come  in  contact with  the  brushes. Use   care   in   undercutting.   DO not   widen commutator   slots   by   removing   metal from   segments,   and  do  not  leave  thin edge  of  mica  next  to  segment. b.   Inspection   and   Tests. (3)  After  the  mica  has  been  undercut,  remove all   copper   and   mica   particles   with   compressed   air. Polish  the  commutator  in  a  lathe  with  number  2/0 sandpaper   while   the   armature   is   rotating   at   1500 rpm.   After   polishing   the   armature,   check   that   com- mutator   diameter   is   not   less   than   1.6470   inches. Replace  if  diameter  is  less. (1)  Inspect  drive  assembly  drive  pinion  for broken,  chipped,  or  badly  worn  teeth.  Replace  drive assembly   if   defective. (2)   Inspect   internal   splines   in   drive   assembly shell  and  pinion  for  cracked,  chipped,  or  broken  con- dition. Replace   drive   assembly   if   defective. 14-19