Page 205 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

194 CHAPTER 8 Cables and Connectors
equal to or less than the width of the contact and rubbing lightly. For female contacts use a 0.22 caliber bore brush with nylon bristles.
O-rings: inspection
Carefully inspect O-rings before every use. O-rings on a bulkhead connector body only need to be checked when the connector is removed from the housing.
Remove the O-ring from the recessed groove where it may be inspected. Wooden toothpicks are a safe way to remove an O-ring without the fear of damaging the O-ring groove. Never use dental picks, awls, safety pins, or other steel objects for removing O-rings! These materials with higher hardness values can easily damage the surface of the groove, the O-ring, or both.
One at a time, run each O-ring between your fingers and feel for any dirt or foreign material. You should also feel a thin film of silicone lubricant on the O-ring. This provides lubricity for the O-ring to slide under pressure into its final sealing position and helps keep the O-ring flexible. If you feel dirt or grittiness, clean the O-ring. The surface should be smooth, continuous, and clean. If not, replace it with a new O-ring. “When in doubt, throw it out.”
Inspect for roundness. Some O-rings could flow and flatten, reducing the compression needed for a good seal. Stretching the O-ring slightly can reveal nicks and cuts and indicate loss of elastic- ity as evidenced by lack of re-bound.
Carefully inspect the recessed groove as well. There should be no foreign material there. Dirt, hair, sand, salt crystals, or any material that is not silicone lube for the O-ring means you will need to clean both the O-ring and the groove. Remove any excess silicone grease as too much grease can prevent the O-ring from properly seating, resulting in a leak path.
O-rings: cleaning
For O-ring cleaning you will need lint-free wipes, such as Kimwipes, isopropyl alcohol, and Q-Tips. Holding the cloth in your hand, grab the O-ring and gently pull it through the cloth. Pull the entire loop through several times until all the foreign material has been removed and the silicone lubri- cant is gone. Once again inspect the O-ring under good lighting as described above, since imperfec- tions, such as cuts or nicks, may be seen more easily without the silicone lubricant coating.
Using a Q-Tip or the lint-free cloth, thoroughly clean the recessed groove. Press the Q-Tip deeply into the groove to access corners and remove residual silicone.
After the groove has been cleaned, inspect for and remove any cotton fibers that may have been shed from the Q-Tip.
O-rings: lubrication and installation
Now you are ready to lubricate the O-rings. For this you will need pure silicone lubricant or sil- icone grease.
Put a small amount of silicone between your thumb and forefinger. Then run the entire loop of the O-ring between your fingers several times. You need to coat the entire surface of the O-ring with a thin film of lubricant. The lubricant film should be thin, uniform, completely cover the o-ring, and have a “wet” feel.
Place or stretch the O-ring back into its recessed groove and be sure it is well seated. Give the O-ring one last look for hair or other dirt that may have fallen on your work.
If you do not need to service an O-ring, it is best to leave it undisturbed. A sealed O-ring will remain so unless disturbed (such as by cleaning).