4O Series SAE Male O-Ring Boss (ORB) Plugs

The 4O Series SAE Male O-Ring Boss (ORB) Plug is a straight hydraulic plug adapter designed to seal off compatible SAE female straight-thread O-ring boss ports (ISO 11926-1 / SAE J1926).
The connection features a standard UN/UNF male straight thread with a pre-installed elastomeric O-ring on the shoulder (E end). When threaded into a compatible spotface port, the O-ring compresses against the port face to form a reliable, leak-tight fluid seal.
This plug provides an efficient sealing solution for hydraulic manifolds, pumps, valves, and cylinders in American and international hydraulic systems.

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Product Description

The 4O Series Plug is a specialized hydraulic sealing fitting designed for straight-thread O-ring boss ports. Unlike tapered threads that seal on the thread flanks, the 4O series relies on straight threads for mechanical retention while achieving its positive seal via an elastomeric O-ring compressed against the port spotface. This port compatibility is specified according to ISO 11926-1 (SAE J1926-1).

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It effectively prevents high-pressure hydraulic fluid leaks in valve blocks, hydraulic motors, pumps, and mobile machinery components. The supplied dimensional table lists multiple thread sizes, corresponding E-end O-ring specifications, thread length A, total length L, and hex size S1. These details assist engineers and buyers in selecting the exact part number for their equipment. NBFK can discuss OEM and customized hydraulic adapter requirements according to customer drawings, samples, or confirmed technical specifications.

Features

SAE UN/UNF straight male thread connection (E end)
Pre-fitted elastomeric O-ring seal for leak-free performance
Mating compatibility with ISO 11926-1 / SAE J1926-1 female ports
External hexagonal body design (S1) for straightforward wrench tightening
Comprehensive range of inch thread sizes available (5/16" to 2.1/2")
Detailed O-ring and dimensional data provided for accurate selection
OEM and customized requirements can be discussed

Specifications

PART NO.	THREAD	O-RING	DIMENSIONS
PART NO.	E	E端	A	L	S1
4O-02Z	5/16"X24	6.07X1.63	7.54	15.2	12
4O-03Z	3/8"X24	7.65X1.63	7.54	15.2	14
4O-04Z	7/16"X20	8.92X1.83	9.1	17	14
4O-05Z	1/2"X20	10.52X1.83	9.1	17	17
4O-06Z	9/16"X18	11.89X1.98	9.9	18.5	17
4O-08Z	3/4"X16	16.36X2.21	11.1	20.3	22
4O-10Z	7/8"X14	19.18X2.46	12.7	23.6	27
4O-12Z	1.1/16"X12	23.47X2.95	15.1	27.7	32
4O-14Z	1.3/16"X12	26.62X2.95	15.1	27.7	36
4O-16Z	1.5/16"X12	29.74X2.95	15.1	28.4	38
4O-20Z	1.5/8"X12	37.46X3.00	15.1	30.5	50
4O-24Z	1.7/8"X12	43.69X3.00	15.1	32.3	55
4O-32Z	2.1/2"X12	59.36X3.00	15.1	36.3	70
Note: E thread end ﬁt with ISO11926-1 port.