How do I care for o-rings?

External o-rings on fill probes, fill ports, and bottle threads need an occasional smear of silicone grease (diver's silicone, not petroleum).

Internal o-rings on PCP valves and regulators are factory lubed and usually last a decade or more without intervention. If a PCP starts leaking, the most common culprits are the fill probe o-ring, the gauge o-ring, or the burst disk. Replacement o-rings should match the size and material (Buna-N or Viton) the manufacturer specifies.