NPK GH1 - Replacing the Seals

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REPLACING THE SEALS
If the gas pressure drops more than 25 psi (2 bar) a day or a large oil leak is found,
replace the seals.
 Check the seals, seal grooves, and piston active seal areas for damage.
1. Small nicks may be removed with a suitable hone.
2. When large or deep nicks are found, replace the part.
GH06 – GH3
A. BODY
P. “B” SLEEVE
PP. U-CUP SEAL
QQ. DIRT SEAL
RR. O-RING
SS. BACKUP RING
1. TOOL END
2. GAS END
NOTE: GHS2 has extra machining for the anti-blank firing feature.
GH4 – GH6
O. “A” SLEEVE
P. “B” SLEEVE
AP. WEAR BAND
PP. U-CUP SEAL
QQ. DIRT SEAL
RR. O-RING
SS. BACKUP RING
1. TOOL END
2. GAS END
(DEFECTIVE SEALS)
ALL DEFECTIVE SEALS SHOULD BE
REPLACED WITH NEW ONES.
41. O-RINGS DEFORMED, WORN,
WARPED, DAMAGED OR
DETERIORATED
42. BACKUP RINGS WORN OR
DEFORMED
43. U-CUP SEALS WORN OR
DETERIORATED
Some minor leakage may be found for a while after new oil
seals are installed, the oil leak will stop when the seal seats
itself in use.