Graco 15D125 0.375″ Diameter Shaft U‑Cup Seal
The Graco 15D125 U‑Cup Seal is a precision-engineered sealing component designed specifically for 0.375‑inch (3/8″) shafts in high-pressure spray and pump systems. Its U‑shaped profile offers excellent dynamic sealing under reciprocating or rotational motion, helping ensure reliable performance in demanding applications.
Key Features
- U-cup geometry for efficient sealing under pressure
- Specifically sized for 0.375″ shafts (3/8″)
- Durable elastomer construction resistant to wear
- Minimizes fluid bypass and leakage
- OEM-grade part for seamless replacement in Graco assemblies
Technical Specifications
| Part Number | 15D125 |
| Seal Profile | U‑Cup |
| Shaft Diameter | 0.375″ (3/8″) |
| Material | High-quality nitrile or similar elastomer |
| Typical Use | Reciprocating or rotating shafts in Graco spray guns and pumps |
Durability & Performance
The U-cup profile of the 15D125 seal generates a strong contact force against the shaft, ensuring a tight seal even during high-pressure operation. Its elastomeric material is chosen for resilience and wear resistance, which helps it maintain sealing performance over extended duty cycles, reducing the risk of fluid leakage or backflow.
Applications & Compatibility
This seal is commonly used in Graco spray guns and fluid-handling assemblies that use a 0.375″ shaft. According to Graco parts documentation, the 15D125 is used in certain Graco texture or airless guns.
- Graco texture spray guns with 0.375″ shaft assemblies
- Graco repair kits for gun fluid sections (where U-cup seals are listed)
Installation & Maintenance
- Clean the shaft thoroughly before installing the seal.
- Lubricate the seal lip with compatible grease to prevent damage upon first operation.
- Ensure correct orientation: the U‑cup’s pressure lip should face the fluid side.
- Inspect for wear periodically; replace if lip deformation or leakage is observed.
- Use non-metal installation tools where possible to avoid damaging the seal.
Frequently Asked Questions
The U‑cup design provides a dynamic sealing lip that maintains better contact under movement and pressure, reducing leaks and improving longevity compared to simple O‑rings.
It is made for shafts with a diameter of 0.375″ (3/8″), common in certain Graco spray guns and pump assemblies.
Replacement frequency depends on usage. Inspect during regular maintenance — if you notice lip wear, leakage, or reduced performance, it’s time to replace the seal.
