FAQs

Q.

Why are the O-rings used with Zero-Leak Gold Plugs smaller than the O-ring used in comparable size SAE and Metric Plugs?
 

A.

The O-rings used with Zero-Leak Gold Plugs are all standard metric sizes and are available in Buna Nitrile 70 durometer as standard and in Viton, EP, etc. materials as special order.

The Zero-Leak Gold Plug O-ring is located under the head of the ZLGP in a recess that has a cross sectional area that is greater than the cross sectional area of the O-ring. The smaller ZLGP O-ring allows it to perform its secondary seal function with less than a 100% port fill rating while its SAE counterpart requires more than 100%. The fact that their fill rate is greater than 100% is a contributing factor that is conducive to O-ring nibbling and extruding.

The convergence of the tapers of the SAE and Metric Plug port and the ZLGP invoke maximum gap minimization and high unit loading at that point. This feature prevents the O-ring from passing between the ZLGP and the wall of the port. Should the metal-to-metal seal fail and therefore require the O-ring (back-up seal) to make the seal, the small diameter O-ring is sufficient to make the seal.

The fact that the ZLGP O-ring does not have any sealing pressure applied to it unless the primary metal-to-metal seal fails, allows the ZLGP O-ring to have a longer useful life than the SAE and Metric plug O-ring, which is under constant pressure of the fluid it is attempting to contain. The ZLGP O-ring won't take a set, be nibbled by the threads of either the ZLGP or port, nor will it be extruded. All of these problem conditions may exist with O-rings used with the old style, O-ring dependent SAE and Metric plugs.

Q.

Are there magnetic Zero-Leak Gold Plugs?

A.

Zero-Leak Gold socket and hex head plugs are excellent for use with Magnets installed. Magnetic plugs are designed to attract metallic particles for removal from fluid systems. The design of the ZLGP allows it to be removed and installed repeatedly without damaging the threads of either the plug or port. The recess under the head of the ZLGP prevents the O-ring, which rests there, from being nibbled by the threads of either the plug or port. This same recess, combined with the engagement of the tapers of the ZLGP and port, prevents the O-ring from being extruded. No chemical sealant of any kind is required with ZLGP. This feature makes installation trouble free and eliminates the possibility of system contamination that may be the result of plug removal and installation. The fact that the ZLGP have two independent seals with the metal-to-metal being the primary seal and the O-ring is the back-up seal, assures that a seal is still possible should the O-ring be lost or damaged when servicing the magnet. Since the ZLGP performance is based on two seals, a replacement O-ring must be installed promptly to insure the total sealing capability of the ZLGP. Typical applications would be truck transmissions, compressor drain / fill, hydraulic gear boxes, diesel engine oil drain / fill, etc.

Q.

What type of O-ring materials are available for use with Zero-Leak Gold Plugs?

A.

The standard O-ring material supplied with Zero-Leak Gold Plugs is buna N 70 durometer. Fluorocarbon, EP, etc. are available upon request. ZLGP use standard metric size O-rings which makes it possible for any commerically available O-ring material to be used with ZLGP.

Q.

What's the lead time to have Zero-Leak Gold Plugs shipped?

A.

Mild steel Zero-Leak Gold SAE and Metric socket and hex styles with either buna N or Viton O-rings are, for the most part, stock items and available for immediate shipment. In the event that an item is not in stock a shipment date will be determined.

An increasing number of stainless steel and aluminum socket head ZLGP sizes are becoming stock items.

The most commonly used SAE and Metric socket and hex head ZLG magnetic plugs are stock.

Custom configured ZLG components have inventory levels established to maintain the Kan Ban, JIT, cell manufacturing, etc. to meet the requirements of their users.

Rush, same day shipments can be made.

Contact an EPCO Applications Consultant for the current ZLGP availability status.

Q.

Is it possible to have the Zero-Leak Gold configuration on other products?

A.

As long as the component has SAE J514 style threads and is used in the SAE J1926 port or metric style threads and is used in the ISO 6149 port, it is probable that the component could be produced with the Zero-Leak Gold design. It is recommended that a drawing be sent to EPCO for evaluation.

Q.

Are there metric size Zero-Leak Gold Plugs?

A.

Yes. Complete information is at EPCO's website under "Plugs & Fittings." The metric ZLGP have the individual sizes, ie., "10 x 1.5" engraved on the head of each ZLGP for easy and positive identification. The same is true for the dash sizes being engraved on the heads of the SAE styles.

Q.

What has to be done to the ports that are in our products to use Zero-Leak Gold Plugs?

A.

Zero-Leak Gold Plugs are interchangeable with SAE J514 style plugs that are used in SAE J1926 ports. In other words, nothing needs to be done other than take out the old style O-ring only SAE J514 plug and install the Zero-Leak Gold Plug. The same applies to the metric Zero-Leak Gold Plugs with the straight thread metric plugs and ISO 6149 ports.

The two seals of the Zero-Leak Gold Plug (metal-to-metal primary and elastomeric back-up) are internal to the port and therefore it is not necessary to spot face the port in order for the ZLG plug to be fully functional.

The SAE J1926 and metric ISO 6149 port drawings may be found at EPCO's website under "Plugs & Fittings."

Q.

Zero-Leak Gold Plugs are low torque...what are the installation torque values?

A.

EPCO commissioned the Fluid Power Institute, located at the Milwaukee School of Engineering, to do tests to determine the Zero-Leak Gold Plug torque values necessary to successfully complete the rigorous fluid power industry standard tests.

The FPI test was conducted using both ductile iron and aluminum manifolds produced to normal industry use standards as specified by the FPI / MSOE. The text of the FPI / MSOE test is available at the "FPI Test Data" site at EPCO's home page.

It is important to note that the mild steel Zero-Leak Gold Plugs completed the entire one million cycles of the test without a failure! The aluminum Zero-Leak Gold Plugs did the same for two millions cycles!

The torque values developed are listed in the FPI / MSOE test report and at "Torque Values" at the EPCO home page listing.

Q.

Why don't Zero-Leak Gold Plugs leak?

A.

Zero-Leak Gold Plugs use both a metal-to-metal and elastomeric seal in their design. The metal-to-metal seal is accomplished by allowing the standard design geometry of the 12 or 15 degree taper that is present at the entry of the SAE J1926 port (see SAE port drawings at our site) to engage the corresponding taper located under the head of the Zero-Leak Gold Plug. As the ZLG Plug is engaged in the port the tapers converge and develop maximum gap minimization between the mating surfaces of the ZLG Plug and the port. This same contact point, by the very nature of the fact that only several thousandths of an inch of both the ZLG Plug and port come in contact, becomes the recipient of high unit loading which supports the metal-to-metal seal.

The O-ring acts as a back-up seal to the primary metal-to-metal seal. The back-up seal is made possible by the O-ring resting in an area under the head of the ZLG Plug that has a cross sectional area that is greater than the cross sectional area of the O-ring being retained. There is no pressure applied to the O-ring as long as the metal-to-metal seal is performing. If for some reason the metal-to-metal would fail, the O-ring acts as the back-up seal and prevents a leak.

The size relationship of the recess and the O-ring prevent the O-ring from being extruded at the spot face and/or nibbled by the threads of either the plug or the port as may be the case with standard SAE J514 or metric O-ring only style plugs.

The gap minimization feature of the metal-to-metal seal does not allow the O-ring to be extruded from the interface. The extrusion of the O-ring in standard SAE and Metric style plugs is a common problem because vibration, pressure spikes, temperature changes can cause the SAE and Metric plug to begin to back out. When the backing out begins this process is supported by the pressure being contained. At some point the plugs back out far enough for the O-ring to begin to extrude out of the interface with a leak path being established.

The same zero-leak performance applies to the metric O-ring straight thread plugs and ports.