Torque the valve head cap screws (15) to 18 lb -ft (25 Nm) before tightening the socket set screw (5)
in order to avoid damage to the valve body (10).
Tighten the socket set screw (5) with the appropriate sized hex key.
Position the gasket (4) and plain cap nut (3) and tighten it with an open end wrench.
Reinstall the tube connections (16, 18) and the inlet connection to the valve head (17).
4-14.5. VALVE HEAD ASSEMBLY, SECOND STAGE.
This task covers: A. Inspect B. Replace
Valve Head Wrench (P/N 004555)
Torque Wrench (P/N 6006NMA)
RTV Sealant NSN 8040-00-225-4548
Grease (Item 17) NSN 9150-00-754-2760
Compressor Secured and Cold
All Air Pressure Purged From System
Second Stage Discharge Valve. Remove and inspect the 2nd stage discharge valve as follows:
Remove the plain cap nut (Figure 4-10, Item 3) and the gasket (4). Inspect the gasket. The gasket
should be replaced If damaged.
Unscrew and remove the socket set screw (5) and the discharge valve cover (6).
Remove the spring washer (7) and the O-ring (8). The O-ring should be undamaged. Replace it if
Extract the discharge valve assembly (9).
Discard the valve gasket (14) and replace It with a new gasket.
Inspect the valve seat (13). The sealing surface must be in good condition: devoid of pitting or
cracking. The maximum valve seat width is 0.039" (1.0 mm)
g. Clean and inspect the valve plate (12). The maximum acceptable groove depth must not exceed
0.008" (0 2 mm).
Check the tolerance of the inside diameter of the valve body (10). The valve body must not show any
grooves at ID 0 669"-0.673" (17.0-17.1mm).
The valve spring (11) is reusable if it shows no outside scuffing and the spring coils are not touching.
Removing the 2nd Stage Inlet Valve. To remove the 2nd stage inlet valve, it is necessary to first remove
the valve head. Proceed as follows: