The Honda 78130-YB4-901 Mechanical Seal is a genuine OEM component designed for Honda WA20, WB20, WB30, WD20, and WD30 water pumps. As a direct OEM replacement, this seal is manufactured to the same specifications as the original, ensuring a proper fit within the pump housing without modification. Confirm your pump's serial number against the fitment table before ordering, as Honda supersedes parts at serial breaks and not every serial range uses the same seal.
Key Features
- Genuine OEM Sealing Integrity — sourced directly from Honda, this mechanical seal meets the same dimensional and sealing standards as the part installed at the factory, maintaining the tight clearances the pump's impeller circuit depends on.
- Broad Pump Compatibility — fits the WA20, WB20, WB30, WD20, and WD30 water pump models, covering Honda's widely used centrifugal pump lineup including both general-purpose and trash-capable variants.
- Critical Leak Prevention — a functioning mechanical seal keeps water from migrating past the impeller shaft and into the engine side of the pump; a worn or damaged seal leads to visible leakage, shaft damage, and loss of prime.
- Serial Number Verification Recommended — Honda updates pump components at specific production breaks, so check your pump's serial number against the compatibility table to confirm part number 78130-YB4-901 is correct for your unit.
The mechanical seal sits at the point where the rotating impeller shaft passes through the pump housing, separating the wet (water) side of the pump from the bearing and engine side. It uses a pair of lapped faces — one rotating with the shaft, one stationary in the housing — pressed together to prevent water from leaking along the shaft. When the seal faces wear, score, or crack, water bypasses the barrier, resulting in external leakage around the shaft, reduced pump output, and potential bearing failure as water reaches lubricated components. Replacing a worn mechanical seal promptly restores the pump's ability to hold prime and deliver full flow.
Part Details
| Part Number | 78130-YB4-901 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Mechanical Seal |
Compatibility & Fitment
| Name | Models | Serial Range |
|---|---|---|
| Water Pump | WA20, WB20, WB30, WD20, WD30 | All |
Verify Before You Order
Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.
Why Buy From DHS Equipment
Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.
Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.
