889-335 supersedes older part numbers: 676-531

Hitachi 889335 — Original Hitachi O‑Ring (P‑7)

Restore a leaky valve or sticky piston with this genuine Hitachi O‑ring (part no. 889335). It’s the small P‑7 JIS‑series sealing ring used in the valve / piston assemblies of Hitachi / HiKoki pneumatic nailers and staplers to keep air seals tight and firing consistent.

Key details

- Designation: O‑Ring (P‑7), Hitachi part 889335.

- Metric dimensions (JIS P‑7): inside diameter 6.8 mm, cross‑section (thickness) 1.9 mm (outer diameter ≈ 10.6 mm). Suitable as the standard P‑7 size used in Hitachi diagrams.

- Function: replacement sealing ring for valve / piston areas in pneumatic finish / Brad / coil nailers — restores airtight compression and prevents misfires or loss of power.

- Fitment examples: listed for several Hitachi / Metabo HPT / HiKoki nailer and stapler models, including N3804A5 / N3804A5M, NT50A5 / NT50A5M, NV75A5 / NV75A5M and NT65M2

Quick usage note: replace any O‑ring that’s cracked, flattened or missing to restore reliable sealing — the P‑7 size matches the original Hitachi specification so it fits into the factory valve / piston grooves without modification.

(If you’re fixing a Hitachi/Metabo HPT / HiKoki nailer, this is the original Hitachi replacement O‑ring specified for those valve/piston seals.)