Section III. OPERATOR MAINTENANCE PROCEDURES
3.2 REPLACE UNISEX COUPLING FACE SEAL/DUST CAP SEAL.
This procedure applies to both 2-inch and 3-inch unisex couplings. The seal in each adjacent coupling face and dust cap
are identical and may be interchanged as a temporary repair.
This task consists of:
Rag, Wiping (Appendix F, Section II, Item 7)
General Safety Requirements:
AAFARS not in operation
Fuels are toxic and flammable. Do not get on
person or clothing. Do not use near open flame.
Area should be well ventilated.
Fuel is flammable. Do not smoke.
The face plate and dust cap of liquid fuel filter-separator unisex couplings employ
a U-ring type seal which is designed to seat with pressure. The seal is slightly
higher than the groove it sits in, so that the top protrudes above the surface.
Pressurized fluid enters beneath this protrusion and expands the seal against the
bottom of the seal groove, and against the corresponding seal in the dust cap or
other face place. Special care must be taken during installation to ensure the seal
is fully seated in the groove. If it is not, pressurized fluid will be forced under the
seal and the coupling will leak.
a. Removal. (Figure 3-1)
Remove face seal (1) by hand.
b. Installation. (Figure 3-1)
Wipe seal groove clean.
Press seal in groove with a smoothing motion of fingertips. Note that when fully seated, the outer lip of the seal
protrudes slightly above the surface. Ensure the seal is not twisted or kinked.