JCB Kingpost Seal / Simmering
Kingpost seal with part number 904/20255, designed for the boom swing systems in JCB machinery. This component plays a vital role in protecting the kingpost main pivot pin, preventing grease leaks and shielding the kinematic joint from the ingress of sand, water, and dust. Made from abrasion-resistant elastomer, the seal maintains its properties even under the extreme loads encountered during digging operations.
Significant product features:
- Sealing Lip: The specialized lip profile ensures excellent adhesion to the pin surface, which minimizes friction and prevents grease from being "forced out" under pressure.
- Chemical Resistance: The material is fully resistant to lithium and calcium-based greases as well as hydraulic oils, preventing the seal from swelling or hardening.
- Anti-seize Protection: An effective dust barrier protects the kingpost bushings and pins from accelerated abrasive wear.
Technical Specification:
| Part Number |
904/20255 |
| Component Type |
Technical seal (Simmering) |
| Installation Site |
Kingpost (Boom swing assembly) |
Application (JCB Machines):
Backhoe Loaders: 1CX / 1CXT, 208, MINI CX
Telescopic Handlers: 513, 558
Technical Advice: Damage to the kingpost seal often manifests as visible grease leakage or excessive play in the pivot pin. When replacing the 904/20255 seal, the condition of the pin surface must be carefully inspected—any pitting or deep scratches can quickly destroy a new seal. It is recommended to use assembly grease during installation to avoid damaging the lip when fitting the component over the edges of the pin.