ARO Y325-214 Nitrile O-Ring | 1/8 in. x 1-1/4 in. OD

ARO Y325-214 Nitrile O-Ring

The ARO Y325-214 is a replacement Nitrile / Buna-N O-ring used in the air-motor and major-valve section of compatible ARO air-operated double-diaphragm pumps.

ARO service documentation identifies the Y325-214 as the small O-ring, Item 113, with dimensions of 1/8 inch cross-section x 1-1/4 inch outside diameter.

Nitrile / Buna-N Material

The Y325-214 is manufactured from Nitrile, also commonly known as Buna-N or NBR. ARO manuals identify its material with code [B], meaning Nitrile.

Nitrile is widely used for pneumatic sealing in compatible compressed-air systems and industrial equipment.

Verified Dimensions

• Part type: O-Ring
• Material: Nitrile / Buna-N
• Cross-section: 1/8 inch
• Outside diameter: 1-1/4 inches
• ARO item reference: Item 113

Major Air Valve Application

The Y325-214 is used in the pneumatic air section rather than the wetted fluid section of compatible ARO diaphragm pumps.

It seals internal components in the major valve assembly and works with spacers and larger O-rings as the air valve redirects compressed air during pump cycling.

Five O-Rings in Applicable Assemblies

Applicable ARO pump manuals list five Y325-214 O-rings in the major-valve assembly.

This quantity refers to the documented pump assembly requirement and should not automatically be interpreted as the supplier sales-package quantity.

Compatible ARO Pump Families

Published ARO documentation shows Y325-214 in multiple Pro-Series and EXP diaphragm pump configurations, including selected:

• 66615X Series
• 66617X Series
• 6661LE Series
• PD20 Series
• PD30 Series
• Related compatible ARO air-motor assemblies

Compatibility depends on the complete pump model and air-valve design. Always verify the full manufacturer model before ordering.

Used with Y325-126 O-Rings

Applicable ARO major-valve assemblies typically use both small and large O-rings:

• Y325-214: Small O-ring, 1/8 inch x 1-1/4 inch OD
• Y325-126: Large O-ring, 3/32 inch x 1-9/16 inch OD

These seals have different sizes and positions and should not be interchanged.

Service Kit Component

ARO air-motor rebuild instructions identify the Y325-214 among the seals replaced during major-valve service. Depending on the pump family, these O-rings are supplied in the applicable air-section service kit.

Maintenance Inspection

Inspect the O-ring during air-motor service for:

• Cuts or nicks
• Flattening
• Hardening
• Surface wear
• Loss of sealing performance

Clean and inspect the valve bore, spacers and mating surfaces before installing new seals.

Ordering ARO Y325-214

Before purchasing, confirm:

• ARO part number Y325-214
• Complete pump model
• Nitrile / Buna-N material requirement
• 1/8 inch x 1-1/4 inch OD dimensions
• Item 113 position where applicable
• Required replacement quantity

Using the exact manufacturer part number helps ensure the correct small major-valve O-ring is selected for the ARO air-motor assembly.