TM 10-3930-671-24 FIGURE 5.21a. the  groove  of  the  advance  power  piston.  Assemble  the advance  adjusting  screw  to  the  piston  hole  plug.  Install new seals to the piston hole plugs. Assemble the spring guide   and   spring   to   the   adjusting   screw.   Install   the pistons    to    the    piston    hole    plugs.    Use    piston    ring compressor  to   aid   in   installing   the   power   piston.   Use care  not  to  damage  the  ring  during  installation  of  the assembly  to  the  piston  hole  plug.  Install  the  adjusting screw nut and a new seal. Install   the   advance   piston   assemblies   into   the   pump housing   (Figure   5.21   b).   A   small   amount   of   grease applied   to   the   end   of   the   pistons   will   keep   the   slide washers in place during assembly. NOTE The sides of the housing near the advance boss bear a  "C"  or  ’CC"  to  denote  pump  rotation.  The  power piston   is   located   on   the   side   marked   -C"   for   a clockwise rotating pump and vice versa. FIGURE 5.21b. Install the advance screw hole plug and new seal into the housing and tighten using plug wrench (Figure 5.21c). FIGURE 5.21c. F-244