O-Ring (Preformed Packing) Boss

TM 5-2420-224-34

3. O-Ring (Preformed Packing) Boss. The boss connection has a straight thread. The seal for this

connection has a preformed packing that fits on top of the thread. This packing is squeezed

into the extra space at the top of the female thread and seals the connection.

4. Flareless. This fitting has a straight thread. The female fitting contains a ferrule that mates with

a cavity in the male fitting. Use care not to overtighten to avoid damage to the ferrule.

5. Installation of Preformed Packings.

a. Before installing a new packing, inspect threads and packing seat for nicks, cracks, and

distortion.

b. Make sure the packing is correct type and size. If not sure, check Repair Parts and

Special Tools List (TM5-2420-224-24P).

c. Before installing a new packing, apply coat of lubricating oil to packing (Appendix B,

Item 30).

d. When installing a packing, always protect it from cuts or nicks. Do not install packing

directly over threads. If available, install packing over a plastic or rubber thread guard

supplied with new fittings. if no thread guard is available, protect packing by wrapping

fitting threads with heavy, smooth, lint-free paper or tape.

e. If a backup washer is used with the packing, it must be free of cuts, nicks, and

distortion. An unserviceable backup washer can cause packing to distort or rupture when

hydraulic pressure is applied, resulting in a leak.

f. Always make sure packing is not damaged, twisted, or distorted after installation.

6. Installation of Adjustable Fittings.

a. Apply coat of lubricating oil (Appendix B, Item 30) to new packing.

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