Serpent SER500904 Shock 13mm Cap O-Ring for RC Dampers  [SER500904]

Cap o-ring: purpose and fit

The Serpent SER500904 Shock 13mm cap o-ring is a compact sealing ring made for use in RC shock cap assemblies. Its main role is to hold shock oil inside the body and stop grit from entering at the cap join, supporting consistent damping behaviour.

Install this o-ring when the original shows signs of flattening, cracking, or leaking oil. Because it seals at the cap rather than the piston or rod, replacing it is straightforward and only needs the cap to be removed from the shock body. Before fitting, clean the groove and check the cap surface for any burrs to ensure a reliable seal.

During tuning, a properly seated 13mm cap o-ring helps keep oil levels steady and damping repeatable between runs. Replace the cap seal whenever you change oil or service shocks to avoid leaks that can upset lap-to-lap consistency.