TM  10-3930-638-24&P 4-3.   FUEL   SYSTEM   MAINTENANCE   (cont) a. Fuel Injector (cont). Injector  body (11) sac hole Valve (7) STEP LOCATION ITEM ACTION REMARKS CLEANING AND INSPECTION (cont) 19 Injector  body Clean Use tip seat scraper P/N 66-0149 as shown (11)  seat  area 20 Clean Use sac hole drill P/N 66-0151 and rotate it to clean deposits from sac hole. Repeat orifice cleaning (step 18 above) 21 Clean Use brush to remove deposits from seat areas, remove varnish with a solvent and felt cleaning  pad.  Inspect  valve  for  pitting  or erosion  which  could  cause  leakage 4-83