TRUCK SERVICE MANUAL TM 5-4210-230-14&P-1 ELECTRICAL DISASSEMBLY If  the  starting  motor  does  not  perform  according  to the  specifications,  it  will  be  necessary  to  disassemble  it  for further tests of the components. 1. Disconnect    the    field    coil    connections    from    the solenoid motor terminal. 2. Remove the thru-bolts. 3. Remove  the  commutator  end  frame  and  field  frame assembly. 4. Remove    the    armature    assembly    from    the    drive housing.    On  some  models  it  will  be  necessary  to remove  the  solenoid  and  shift  lever  assembly  from the   drive   housing   before   removing   the   armature assembly. 5. Remove the thrust collar from the armature shaft. 6. Remove  the  pinion  from  the  armature  by  sliding  a metal cylinder onto the shaft; with a hammer striking the   metal   cylinder   against   the   retainer,   drive   the retainer  toward  the  armature  core  and  off  the  snap ring, Fig.  7. Fig.  7  Removing Retainer from Snap Ring 7. Remove    the    snap    ring    from    the    groove    in    the armature shaft. 8. Roll  type  clutches  are  designed  to  be  services  as  a complete  unit;  therefore,  do  not  disassemble.    If  the condition   of   the   clutch   assembly   is   questionable, replace it. INSPECTION AND REPAIR 1. Brushes and Brush Holders:  Inspect  the  brushes  for wear.  If they are worn down to one-half their original length,   when   compared   with   a   new   brush,   they should be replaced. Clean brush holders and be sure that the brushes will not bind in the holders.  The full length of the brush surface   should   ride   on   the   commutator   with   the proper  spring  tension  (see  specifications)  to  provide a good contact.  Inspect the brush leads and screws to be sure they are tight and clean. 2. Armature:  Inspect the armature to be sure there are no short circuits, opens, or grounds. a. Short    circuits    are    located    by    turning    the armature   in   a   growler   while   holding   a   steel strip   on   the   armature.      The   steel   strip   will vibrate on the area of the short circuit, Fig.  8. Fig.  8  Testing Armature for Short Circuits b. Opens are usually found where the conductors are joined to the commutator.  Loose or poor connections  will  cause  arcing  and  burning  of the  commutator.    If  the  bars  are  not  burned too bad, resoled the leads in the riser bars and turn  the  commutator  down  in  a  lathe.    Then under cut the insulation between the commutator bars 1/32". CTS-2258-K  Page 7 PRINTED IN UNITED STATES OF AMERICA