TM 5-4220-211-12&P
NOTE
Do not overtighten vice. Valve head damage may occur.
(7)
Using valve tool (Fig. D-15) remove inlet valve assembly (4, Fig. D-6).
(8)
Clean all components in mineral spirits. Metallic components may also be cleaned in lacquer thinner.
Remove all carbon deposits.
(9)
Inspect valve plates (7, Fig. D-6), valve seats (5, 23, Fig. D-6) and valve springs (8, 17, Fig. D-6) for
wear and damage. Plates and seats should be free from pits, corrosion, carbon and excessive wear.
Springs should be free from worn spots. Always replace valve plates and seats in assemblies.
(10) Lapping of plate and seat surface is necessary even on new valve parts. Using a lapping compound,
grit #2-A or equivalent. Lapping surface should have a smooth uniform surface free from scratches,
pits, or indentations.
(11) Replace gaskets (14, 5, Fig. D-6) and O-ring (10, Fig. D-6).
(12) Assemble intake valve as shown (4, Fig. D-6)
(13) Place valve head upside down in vice. Using valve tool, Fig. D-15), screw valve assembly into head
being careful not to tighten down on valve plate (7, Fig. D-6). Tighten down tight with valve tool.
(14) Center punch two places on edge of threads to secure inlet valve cover (16, Fig. D-6) in valve head.
(15) Assemble outlet valve assembly as shown (3, Fig. D-6).
(16) Install spring plate and O-ring (11, 10, Fig. D-6) on plug (12, Fig. D-6).
(17) Install valve assembly (3, Fig. D-6) into plug (12, Fig. D-6).
(18) Screw plug (12, Fig. D-6) and valve assembly (3, Fig. D-6) into valve head. Torque plug down to 18 ft
lbs (25 NM).
(19) Install stud (13, Fig. D-6) into plug (12, Fig. D-6) pull down (by hand) tight with allen wrench. Install
movement of valve plates (7, Fig. D-6).
(20) Align valve head on top of cylinder with inlet and outlet tubes. Install 6 socket head screws (18, Fig. D-
6) and torque to 18 ft-lbs (25 NM).
(21) Connect inlet and outlet lines and tighten securely.
(22) Install gasket (24, Fig. D-11) and safety valve (23, Fig. D-11). Tighten securely.
NOTE
Do not readjust safety valve.
m.
Third Stage Valve Replacement. Third stage valves are replaced as assemblies only.
4-6