Graco 15F748 Piston Seal

The Graco 15F748 Piston Seal (U‑Cup, E10) provides dependable, leak‑tight sealing around the piston in Graco pump assemblies — ensuring smooth piston action, pressure retention, and reliable performance.

Part No: 15F748
Function: Dynamic piston seal to maintain pressure and prevent leaks
Design: U‑Cup style, OEM‑grade seal for durability and proper fit
Use Case: Replacement seal for Graco displacement pumps and spray systems
Maintenance Friendly: Replaceable component in rebuilds to restore pump performance

$31.6

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Description

Product Overview

The Graco 15F748 Piston Seal (U‑Cup, E10) is an OEM‑grade piston seal designed to provide a reliable and leak‑tight barrier between the piston and cylinder bore in Graco pump assemblies. It ensures proper sealing under pressure, smooth piston reciprocation, and effective fluid containment — helping maintain pump efficiency and prevent internal leaks even during demanding industrial spray or coating operations.

Key Features

OEM quality: Genuine Graco part manufactured to original specifications for correct fit and seal integrity.
U‑Cup design: Provides effective dynamic sealing around the piston, maintaining pressure and preventing fluid bypass.
Durable construction: Built to withstand repeated piston cycles, high pressure, and fluid contact for long-term service life.
Smooth piston operation: Ensures piston moves freely with minimal friction while preserving a tight seal — optimizing pump performance and reducing wear.
Included in repair kits: Listed as part of official Graco displacement‑pump repair kits, facilitating rebuilds and maintenance.

Specifications

Specification	Details
Part Number	15F748
Type	Piston Seal (U‑Cup, E10)
Application	Sealing piston in Graco pump cylinders to maintain pressure and prevent leaks
Included in	Graco displacement pump repair kits / rebuild kits
Condition	New, OEM‑grade replacement seal

Maintenance & Installation

Before installation, ensure the cylinder bore and piston surfaces are clean, free from debris or old seal remnants to prevent scoring or seal damage.
Lubricate lightly (as per manufacturer guidelines) to ease insertion and avoid seal lip damage during install.
When rebuilding a pump, always replace related components (e.g. bushing, rod seal, o‑rings) together to maintain optimal sealing and performance.
After installation, test under pressure to check for leaks before returning to regular use.
Inspect periodically for wear, lip hardening, or deformation — replace if seal shows signs of degradation to prevent leaks or loss of pressure.

Frequently Asked Questions

It seals the piston against the cylinder wall, maintaining pressure during the pump’s operation and preventing fluid bypass or leaks.

Yes — 15F748 is a genuine OEM piston seal from Graco, ensuring compatibility, proper tolerances, and reliable sealing performance.

Replace the seal if you notice leakage, loss of pressure, poor piston movement, or if the seal shows visible wear, cracking or hardening — these indicate the seal is no longer effective.