Hitachi 302-429 Spare Part - Dust Washer (b)

Genuine Hitachi part 302-429 — Dust washer / dust seal (B)

Description:

This is the original Hitachi dust washer (part no. 302-429), the small circular dust washer/seal that sits next to the motor/bearing assembly to keep dust and debris away from the armature and fan. It’s supplied as the factory replacement part used in Hitachi rotary-hammer / hammer-drill assemblies and is referenced in Hitachi parts diagrams as “Dust Washer (B)” / seal.

What it does (and where it sits):

302-429 functions as a protective washer/seal at the shaft/bearing interface — typically located adjacent to the 6201 ball bearing and the cooling fan or armature housing. Replacing a worn 302-429 restores the original dust barrier that helps extend the life of the bearing and armature. The parts diagrams show it immediately beside the 6201 bearing and fan components in the assembly.

Materials & fit notes:

- Factory-design dust washer sized to Hitachi tolerances (circular plate with a centre bore to pass the motor shaft).

- Intended form/fit for the listed Hitachi tool gearboxes/armature assemblies; install orientation follows the factory diagram (washer seats against the bearing/fan area). Exact bore and outer diameters are specific to the tool’s shaft and are matched to the original part number shown in the service diagram.

Example Hitachi models that use part 302-429:

- H45MRY (Hammer/rotary models).

- H45SR.

- DH40MRY / DH40MR (rotary-hammer / hammer-drill series).

- H41MB (listed in Hitachi exploded diagrams).

Quick installation tip:

When fitting 302-429, clean the shaft and bearing seating area, check the adjacent 6201 ball bearing and fan for wear, then position the washer so it seats flush against the bearing/housing per the exploded diagram. No additional machining is required — it’s a direct-fit replacement for the listed Hitachi models.

If your tool’s parts diagram lists 302-429 in the motor/gearbox assembly, this genuine Hitachi dust washer is the like-for-like factory replacement to restore the dust seal function.