TM  10-3930-638-24&P 4-3.   FUEL   SYSTEM   MAINTENANCE   (cont) b. Fuel Injection Pump (cont). STEP LOCATION ITEM ACTION REMARKS REASSEMBLY NOTE All parts must be flushed in clean diesel fuel as they are assembled. 24 Hydraulic a. Vent wire (132) Install in vent head (81) wire  retainer  (131) b. Vent wire Install In  hydraulic  head  (81) retainer  (131) c. Two plug screws Install (130) d. Plug screw (129) Install 25 Housing a.  Nameplate  (128) Position (133) b. Two screws (127) Install c.  Two  bushings Install Use soft hammer (134) 26 End  plate a. Seal (93) Install On sleeve (92) (88) b. Filter element (94) Install On sleeve (92) c. Seal (95) Install On sleeve (92) d.  O-ring  (96) Install On sleeve (92) e.  Regulator Install In  sleeve  (92) spring  (97) f.  Regulating Install On sleeve (92) piston  (98) g. Seal (99) Install On  regulating  piston  (98) h. Sleeve (92) Install In end plate (88); be careful not to disturb parts assembled to sleeve. Finger tighten sleeve i. Plug (91) Install In  sleeve  (92) j. Seal (90) Install On plug (89) k. Plug (89) Install 27 Hydraulic NOTE head  (81) Pumping plungers are graded in four sizes A through D in either standard or oversize. The correct grading letter is etched on the rotor (123) base; if a “- 2“ is also etched on rotor base, this indicates an oversize pumping plunger is required. Absence of a “-2” indicates a standard size plunger in either size A through D, as etched on rotor base, is required. 4-115