ARMY TM 9-2815-255-24 AIR FORCE TO 38G1-95-2 MARINE CORPS TM 2815-24/4 b. Using two wrenches, loosen fuel line connection at injection nozzle. c. Crank  engine  over  with  starter  (but  do  not  start  engine),  until  fuel  free  from  bubbles  flows  out  of  loosened connection.  Tighten connection to 20 ft-lbs (27 Nm). d. Repeat procedure for remaining injection nozzles (if necessary) until engine starts or until air has been removed from fuel system. 3-24.  FUEL FILTER/WATER SEPARATOR. 3-24.1.  Prefilter and Element Replacement. WARNING Diesel  fuel  is  flammable  and  toxic  to  eyes,  skin,  and  respiratory  tract.    Skin/eye  protection required.  Avoid repeated/prolonged contact.  Good general ventilation is normally adequate. NOTE Retain any items removed from fuel filter that are not part of the filter for installation purposes. NOTE Catch fuel in suitable container. a.    Remove  cap  retaining  ring  (1,  FIGURE  3-40),  header  (2),  volume  plug  (3),  and  prefilter  (4).    Inspect  seal  (5)  for damage and replace as necessary.  Install new prefilter (4), seal (5), volume plug (3), header (2), and cap retaining ring (1). b.  Loosen and remove retaining ring (6) and filter element (7) from filter head.  Discard packing (8).  Install new filter element (7) with new packing (8) and secure with retaining ring (6). 3-24.2.  Removal. CAUTION Always use two wrenches when removing/installing fittings and/or fuel lines to avoid damage. a. Disconnect fuel line (9, FIGURE 3-40) from elbow (10) at filter head (15).  Cap openings. b. Disconnect fuel line (11) from elbow (12) in outlet of filter head.  Cap openings. c. Remove two capscrews (13) and washers (14) securing filter head (15) to engine block; remove filter assembly. 3-24.3.  Repair. a. Remove fuel filter, refer to paragraph 3-24.2. b. Remove two elbows (10 and 12, FIGURE 3-40) from filter head (15). c. Remove bleed screw (17) and preformed packing (18).  Discard preformed packing (18). d. Install new preformed packing (18) and bleed screw (17). e. Install two elbows (10 and 12) in ports of filter head. Change 3  3-73