The Zero-Leak Gold Plug employs a very simple, geometry-reliant method of sealing for dependable zero-leak performance in all SAE J1926 and Metric ISO 6149 straight thread port entry plug applications. Available in hexagon and socket head styles, Zero-Leak Gold plugs can be made in mild steel, stainless steel and aluminum in sizes -00 through -32. Any commercially available O-ring material may be used with ZLG plugs, and magnetic plugs and fully custom plugs are also available for unique applications. All ZLG plugs provide zero-leak performance—guaranteed.

Two-Seal Design

Zero-Leak Gold plugs have two seals. The first seal is a metal-to-metal seal created by the engagement of a taper in the SAE J1926 or ISO 6149 port with a mating taper in the ZLG fitting design. This engagement is several thousands of an inch long for minimal gap and high unit loading. This engagement also causes the removal torque to be greater than the insertion torque, as documented in the Fluid Power Institute tests conducted at the Milwaukee School of Engineering. See the FPI Test Reports >

The second seal is an elastomeric O-ring seal located under the taper in the ZLG fitting, which acts as a backup seal should there be a failure with the primary seal. The Zero-Leak Gold O-ring cannot be extruded onto the spot face of the port, which prevents ZLG plug from “backing out” as SAE J514 ORB Plug counterparts are prone to do. The O-ring also cannot be forced into the interface of the threads of the plug or port, where it could be nibbled or damaged.

ZLG Plug Advantages

Zero-Leak Gold plugs offer a number of advantages over standard SAE J514 and ISO port entry straight thread plugs. ZLG plugs can be resealed repeatedly without loss of effectiveness, and this resealing will not damage the plug or the port threads. They have a low profile design compared to standard SAE counterparts, and they require no chemical sealants, which eliminates the risk of fluid contamination during removal and reinsertion. And Zero-Leak Gold plugs are guaranteed not to leak or back out, even in vibration, temperature change and pressure spike situations.

ZLG Plug Sizes

Socket Head Plugs – Data Sheets

Hex Head Plugs – Data Sheets

Custom ZLG Plugs

Need a size or spec you don’t see listed here? Zero-Leak Gold plugs are available in custom configurations for unique applications.

Zero-Leak Gold Plug Applications

ZLG plugs are extremely easy to use and are fully interchangeable with standard SAE ORB plugs that have been used for years in SAE J1926 and metric ISO 6149 ports.


Access Ports


Agriculture Equipment

Air Conditioning

Amusement Ride Equipment

Automotive Equipment Rebuilders

Brake Systems


Construction Equipment



Diesel Engines


Fuel Dispensers


Hydraulic Controls

Hydraulic Lawn Care Equipment

Injection Molding Equipment

Logging Equipment

LP or Natural Gas Engines


Release Valve

Marine Engines

Mining Equipment

Off-Highway Equipment


Refrigerant Recycling Equipment

Refrigerant Systems

Test Equipment

Transmission Drain/Fill Plugs

Upgrades from Pipe Plug Applications

Work Holding