Graco 166178 Packing O-Ring
$402.00
In Stock
The Graco 166178 Packing O-Ring provides a tight, leak-free seal inside pump assemblies, ensuring consistent spray pressure and smooth operation.
- OEM-grade nitrile rubber seal
- Prevents internal fluid leaks
- Maintains proper pump pressure
- Designed for Graco Ink Supply Pump 306805
Quantity
Genuine OEM Part
Fast Shipping (Order by 1 PM CST)
Easy Returns
Sealing O-Ring Details & Fitment
Compatible Machines
This listing covers the exact model(s) where part number 166178 is explicitly called out in the official parts diagram.
- Graco Ink Supply Pump — Model 306805
Key Specifications
| Part Number | 166178 |
|---|---|
| Item Type | Packing O-Ring |
| Material | Nitrile rubber (NBR) |
| Primary Function | Creates a pressure-tight seal in the pump lower to prevent fluid bypass and leakage. |
| Typical Location | Installed at the bottom of the fluid cylinder in the pump assembly. |
Overview & Benefits
- Maintains system pressure and reduces downtime from leaks.
- Durable elastomer suited for paints, inks, coatings, and common solvents.
- OEM geometry for correct compression and long service life.
Fitment Guidance
For any sprayer or pump not listed above, verify by checking the model’s parts breakdown. Use the exact model designation and serial-range diagram to confirm the presence of part 166178.
Frequently Asked Questions
It seals the fluid end so the pump can build and hold pressure without internal bypass. A worn O-ring causes hard-to-prime behavior, pressure drop, or visible leakage.
Open your model’s official parts manual and search the bill of materials or exploded view for the exact part number 166178. If that number is listed, it’s the correct seal for your unit.
Clean the groove and mating surfaces, lightly lubricate per the service manual, and avoid twisting during insertion. Inspect adjacent packings and bearings and replace if worn to maximize seal life.
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