TM  10-8110-201-14&P Section VIII. MAINTENANCE OF PRESSURE CONTROL 4-19. Pressure Control (Fuel Drums Only). a. Cleaning and Inspection (Exterior), Testing and  Adjustment. (1) Using  a  mild  soap  and  water  solution  with  a stiff bristle brush, remove foreign matter from the pressure  control. (2) Inspect  pressure  control  for  cracked,  loose, or  missing  parts. (3) Test  and  adjust  pilot  valve  (para  4-22). b. Repair. When  it  becomes  necessary  to  repair and  adjust  the  pressure  control,  the  procedures  in paragraphs 4-20 thru 4-25 will be followed as re- quired. 4-20.  Diaphragm  Valve. a. Removal and Disassembly. (1) Remove  the  plug  (1,  fig.  4-10)  from  the  cover (3)  as  necessary. (2) Hold down the cover (3) firmly to prevent spring action and remove the nuts (2) from studs (14). Gradually release the pressure on the cover and  remove  the  cover  from  the  studs. (3) Unscrew and remove guide shaft (4) from cover  (3). (4) Remove spring (5) from the pressure con- trol. Lift the diaphragm valve from the pressure control. (5) Remove the nut (6) from machine screw (13). (6) Remove  the  large  washer  (7),  diaphragm  (8), poppet (9), disk (10), spacer (11) and small washer (12) from the machine screw (13). b. Cleaning, Inspection and Repair. (1) Wash all metal parts in a hot, mild soap and water  solution  and  dry  the  parts  with  a  clean  cloth. (2) Inspect  the  machine  screw  and  guide  shaft to  determine  if  they  are  bent,  cracked,  broken,  bur- red  or  have  stripped  threads. (3) Inspect  the  nut  for  stripped  threads  and  a burred   surface. (4) Inspect the diaphragm and disk to deter- mine  if  they  are  cut  or  deteriorated. (5) Inspect the spring to determine if it is broken  or  collapsed. (6) Inspect  the  poppet,  spacer  and  washers  to determine  if  they  are  cracked  or  burred. (7) Replace all unserviceable parts. c. Reassembly and Installation. (1) Place  the  small  washer  (12,  fig.  4-10), spacer  (11),  disk  (10)  and  poppet  (9)  on  the machine  screw  (13). (2) Place the diaphragm (8) on the machine screw  (13). (3) Place  the  large  washer  (7)  on  the  machine screw  with  the  raised  side  against  the  diaphragm. Install the nut (6) on the machine screw and tighten it  securely. (4) Align the holes in the diaphragm valve in the  pressure  control. (5) Screw the guide shaft (4) into the cover (3). (6) Place the spring (5) over the diaphragm valve. (7) Align the holes in the cover with the studs, and  place  the  cover  on  the  pressure  control. NOTE Assure the guide shaft is in the hole in the machine screw. (8) Install  nuts  (2)  on  the  studs  and  tighten  the nuts  to  20  foot-pounds  (2.77  m-kg)  torque. (9) Insert  plug  (1)  in  cover. 4-21. Cycling Valve Assembly. a. Removal and Disassembly. (1) Hold the ring (2, fig. 4-1 1) in place and remove  the  capscrews  (1). (2) Remove the ring (2) and cover (3) from the pressure  control. (3) Grasp the button (4) and twist and pull it until  the  cycling  valve  is  removed  from  the pressure  control. (4) Remove the preformed packings (11) from the  valve  body  (12). (5) Apply pressure on the spring (8) with the washer (9) and remove the retaining ring (10) from the valve body. (6) Remove the retaining ring (13) from the cycling valve stem (6) and remove the valve body from the cycling valve stem. (7) Remove  the  washer  and  spring  from  the cycling  valve  stem. 4-19