AS568-366 Buna-N Nitrile X-Ring (Quad Ring), 70A Durometer, (7.225" x 0.210" Actual) - Low-Friction 4-Lobe Seal

FINAL SALE - NO RETURNS. THIS IS A STANDARD CATALOGUE SIZE; CONFIRM YOUR DIMENSIONS AND MATERIAL BEFORE ORDERING.

Because standard sizes are chosen by measurement rather than by machine model, they ship as final sale. If we send the wrong item, or it arrives damaged or defective, we replace it free of charge, and that never changes.

Is a standard o-ring rolling, twisting or wearing out too fast in a moving joint? An X-ring (also called a quad ring) has four lobes and two sealing contact lines, so it runs with less friction and resists the spiral twist that kills o-rings in reciprocating and rotary service.

This Beaver Island Parts Company x-ring (quad ring) is a standard AS568-366 183.51mm ID x 5.33mm CS (7.225" x 0.210") size, molded in 70A Buna-N Nitrile. Its outside diameter is 194.17mm (7.644").

Specifications

What It Fits

This size is used across pumps, valves, hydraulic and pneumatic fittings, filter housings, gearboxes, compressors, pressure washers and plumbing. If your manual, parts list or old ring calls for AS568-366 183.51mm ID x 5.33mm CS (7.225" x 0.210"), this is the part.

Why Buna-N Nitrile

Buna-N is the all-round workhorse of sealing: tough, abrasion resistant and the right default for oil, hydraulic and water service. Recommended for petroleum oils, hydraulic fluid, greases, water, air, and most fuels. Not recommended for brake fluid (glycol), ketones such as acetone or MEK, and long-term sunlight or ozone exposure.

You Can Do This Repair

Install exactly like an o-ring in the same groove: clean, lubricate, and seat it without twisting. X-rings are dimensioned to drop into standard o-ring glands.

Pro Tip: A thin coat of Aqua Flex silicone lubricant eases installation, protects the seal on first start-up and extends its life.

Shipping: This part is special-ordered and packed for you. It ships from our facility in about 10 business days, then transits by the carrier service you choose at checkout. The estimated delivery date shown on this page includes that lead time.

Why Buy From Beaver Island Parts Company

• Every dimension published. Size, material, hardness and temperature rating are listed up front so you can confirm fit before you buy, not after.
• Inspected, packed and labeled by us. Each order is checked and repacked in a bag labeled with the part's size and material, so it never gets lost in a parts bin.
• Real people who answer fitment questions. We are an American family-owned and operated small business. Send us your measurements or model number and we will help you confirm the right part.
• Replacement guarantee. If we ship the wrong item, or it arrives damaged or defective, we replace it free of charge.

Frequently Asked Questions

Q: Will this fit my equipment?
A: It fits any groove or fitting that calls for a AS568-366 183.51mm ID x 5.33mm CS (7.225" x 0.210") x-ring (quad ring). Size, not brand, determines fit for standard o-rings. Measure the old o-ring's inside diameter and cross-section with calipers, or better, measure the groove, because a used ring stretches and flattens. Match the material to the fluid: the right size in the wrong rubber will still fail.

Q: What is Buna-N Nitrile good for?
A: It is suited to petroleum oils, hydraulic fluid, greases, water, air, and most fuels. Avoid brake fluid (glycol), ketones such as acetone or MEK, and long-term sunlight or ozone exposure.

Q: Can I install it myself?
A: Yes. Most o-ring replacements take only a pick tool, a clean rag and lubricant. Release pressure, drain the system if needed, remove the old ring, and follow the installation notes above. If it is your first time, take a photo before you take anything apart.

Q: When will it ship?
A: It ships from our facility in about 10 business days, then transits by the carrier service you choose.