Replacing the O-ring

Refer to Opening and closing the instrument for details on accessing the O-ring.

The O-ring removal tool and silicone compound are available in the support kit.

Care for the O-ring is the single most important item of maintenance on any submersible RBR instrument. A water leak can damage the circuit board beyond repair and cause complete data loss. Every instrument seal depends upon its O-ring, not the end-cap tightness. Therefore, proper O-ring maintenance is crucial.

The O-ring may lose elasticity over time, even when the instrument is not deployed. RBR strongly recommends replacing the O-ring regularly.

Location of the O-ring

To access the O-ring, open the instrument.
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Figure 1. Location of the O-ring

Inspecting the O-ring

Visually inspect the new O-ring for nicks and scratches before installing it. Pay attention to the following areas:

  • The surface of the O-ring itself

  • The mating surface on the inside of the case between the threads and the open end

  • The groove in the end-cap where the O-ring sits

When handling the O-rings:

  • Avoid using any object that could scratch the O-ring or any of its mating surfaces.

  • If dirt is present in the O-ring groove, remove the O-ring as described below and thoroughly clean the groove.

  • Do not return this old O-ring to the instrument! If you remove the O-ring from the instrument for any reason, always replace it with a new one.

  • If the surfaces of the O-ring groove are scratched, pitted, or damaged, contact RBR for advice.

Replacing the O-ring

Do not use metal screwdrivers or any other metal tool! They may scratch the O-ring groove and render the end-cap useless.

  1. Use the plastic O-ring removal tool (included in the support kit) to remove the old O-ring from its groove. The O-ring may need to stretch quite a bit as it is pushed off. This requires some effort, but can be done by hand.

  2. Clean the groove thoroughly with a soft, lint-free cloth and compressed air, if necessary.

  3. Select a new O-ring and inspect it for damage.

  4. Lubricate with a very light film of silicone compound (included in the support kit).

  5. Install the new O-ring by pushing it into place and popping it into its groove.

  6. Once in place, inspect it once more for scratches and debris, and wipe away any silicone compound deposited on the end-cap.

  7. Close the instrument.