Replacing the O-ring

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.
screen shot 2022 03 30 at 8 48 14 am

Location of the O-ring

To access the O-ring, open the instrument.

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

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 tool (included in the support kit) to remove the 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 the proper O-ring and inspect it for damage.

  4. Lubricate the new O-ring 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 the new O-ring is in place, inspect it once more for scratches and debris, and wipe away any silicone compound deposited on the end-cap.

  7. Once the inspection is complete, close the instrument.