Hitachi Damper - 321-289

Hitachi 321289 — genuine Hitachi damper (impact buffer) designed for the hammer/rotary-hammer mechanism. This compact rubber/elastomer damper cushions the striker and reduces shock, vibration and noise inside the hammer assembly so the tool returns to consistent striking performance when the original damper is worn or damaged. The part is listed as 321289 (also shown as 321‑289) and fits Hitachi/Hikoki models such as DH40MR, DH40MRY, H41MB2.

Supplied as the single damper component for the internal impact group, it’s a direct replacement designed to seat into the factory damper holder and restore proper clearances and damping in the impact mechanism. If your hammer is showing reduced impact, excessive vibration, or abnormal noise, replacing part 321289 restores the intended damping behaviour.