TM 55-2840-241-23 Change 19          5-4.1 (6) Remove any fuel  that may have been spilled in the engine compartment and resafety the upper bleed port. f.   Engine fuel pump filter bypass valve. (1) Testing (a)    Remove  fuel  filter  (Refer  to  paragraph 5-10). (b)    Install cap, NAS 813-14 or NAS 813-8 on the filter boss. (c) Remove the after filter sense line from the fuel pump and install AN815-3 fitting in the after filter port (marked AF). (d)    Install  approximately  36  inches  of  3/8 inch clear plastic tubing (table  2-2, item 43) on the fitting and install a small funnel in the free end. (e)    Fill the tubing with fuel to raise the fuel level 12 to 24 inches above the pump port. (f) Observe the filter housing area for leak- age, leakage exceeding 10 drops per minute is not ac- ceptable (refer to paragraph f(2), for corrective action). (g)    With the cap still installed over the filter boss, install filter cover. Provide a container to catch fuel from the tubing on the after filter port. (h)    Momentarily    actuate    the    fuel    boost pump. The fuel filter caution light should illuminate and fuel should flow from the tubing indicating the pump is working. (Refer to paragraph 5-10f(2) for corrective pro- cedures if the bypass is not working). (i) Reinstall the cap from the filter boss and remove the fitting and tubing from the pump port. (j) Reinstall after filter sense hose. (k) Replace  fuel  filter  (refer  to  paragraph 5-10). (2) Corrective procedures. If fuel pump failed by- pass  test  in  paragraph  f(1)(f)  or  f(1)(h)  then  clean  as follows: (a)    Remove fuel pump (refer to paragraph 5-9). (b)    Remove  fuel  filter  (refer  to  paragraph 5-10). (c) Remove and clean the bypass valve as follows. 1 Argo-Tech/TRW pump, NSN 2915-01-070-5675, P/N 6899253. a Cut  and  remove  lockwire  which retains the filter bypass valve in the gear housing. b Unscrew  and  remove  the  valve housing (refer to TM 55-2840-241-23P, figure 22, item 17). c Remove   spring,   item   20   and valve, item 19. d Clean the rubber face of the valve using petroleum solvent. e Inspect  for  excessive  deteriora- tion of rubber.  If deteriorated, replace item 19. f Clean seat in the pump and filter bowl area using petroleum solvent. g Install the filter bypass valve, en- sure  that  rubber  face  is  against  the  seat,  and  install spring. h Replace  o-ring,  item  18.  Lubri- cate and install it in groove in the filter bypass. i Screw  valve  housing  into  gear housing. Torque 75 to 100 inch lbs. 2 Sunstran/Pesco pump NSN 2915-01-109-7171, P/N 23003114. a Cut  and  remove  lockwire  which retains the cap (refer to TM 55-2840-241-23P, figure 11, item 2). b Unscrew and remove cap (11). c Remove spring (14), shim (15) if installed, piston (16), and sleeve (17). d Clean the piston and sleeve using petroleum solvent. e Clean the gear housing at the by- pass  valve  area  and  filter  bowl  area  using  petroleum solvent. f Replace   o-ring   (18).   Lubricate lightly and engage in sleeve (17). g Install sleeve in gear housing. h Install  piston  in  sleeve,  shim  (if installed) and the spring. i Replace   o-ring   (12).   Lubricate and install in the groove on the cap. j Screw cap into gear housing and torque to 140-160 inch lbs and safety wire. 3 Pump, NSN 2915-00-924-7791, P/N 6854292.