Graco 119790 O-Ring Packing

Graco 119790 O-Ring Packing — genuine OEM seal designed for maintaining pressure and preventing fluid leaks in Graco GMAX II spray machines.

OEM Part Number: 119790
Fits: GMAX II 3900, 5900, 7900
Ensures tight seal and consistent spray pressure
Durable material for long-lasting performance
Easy to replace during routine maintenance

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Description

Compatible Machines for the 119790 O-Ring Packing

Graco GMAX II 3900 — listed in parts list referencing part # 119790. :contentReference[oaicite:1]{index=1}
Graco GMAX II 5900 / 5900HD — part # 119790 appears in list of repair parts for this model. :contentReference[oaicite:2]{index=2}
Graco GMAX II 7900 — repair parts quick reference shows 119-790 / 119790 for this model. :contentReference[oaicite:3]{index=3}

Product Overview

This is the genuine Graco part number 119790, a precision O-Ring packing used in high-performance airless spray systems. It’s designed to maintain a reliable seal within the fluid section of compatible Graco GMAX II machines.

Key Features:

OEM quality packing, direct replacement for worn or damaged sealing rings.
Supports proper fluid section performance and prevents leaks around piston/cylinder or pump housing.
Used in commercial-grade airless sprayers: GMAX II 3900, 5900, 7900 series.
Easy to install as part of routine maintenance on the compatible machines listed above.

Technical Specifications

Part Number	119790
Description	Packing, O-Ring, fluid section seal
Applicable Series	GMAX II 3900 / 5900 / 7900
Function	Sealing within pump/displacement assembly to maintain pressure and prevent bypass

Why Choose This O-Ring?

When servicing your spray equipment, installing the correct packing O-Ring ensures continued performance and prevents downtime due to leaks or seal failure. Using the OEM 119790 for the machines listed above ensures compatibility, correct dimensions, and reliable service.

Maintenance Tip: Inspect the old packing for deformation, hardening, or chemical damage. Clean the seating surface before replacement, lightly lubricate if recommended, and ensure correct orientation during reassembly.

Frequently Asked Questions

The part is confirmed for the models listed above. If your machine is outside those series, check the parts manual to confirm whether 119790 is specified. Fitment on other machines is not guaranteed without verification.

The replacement interval depends on usage, fluid type, and pressure conditions. However, during a major service or if you notice leaks or pressure loss, replacing the packing is good preventative maintenance.

Use only the lubricant specified by your machine manufacturer (often a light film of the coating material’s compatible fluid or a specified seal‐lubricant). Avoid petroleum grease unless approved, especially for systems pumping coatings or resins.