Mil-spec O-ring family, nitrile, petroleum hydraulic fluid
MS28775 O-rings: nitrile to MIL-PRF-25732, sized to AS28775
MS28775-XXX is a nitrile (NBR) O-ring for petroleum hydraulic fluid, in the AS568 size the dash names. It is made to MIL-PRF-25732, the same document as MIL-P-25732 and MIL-DTL-25732, and the MS drawing's SAE successor is SAE-AS28775. MIL-PRF-25732 is inactive for new design but still maintained and procurable, and it carries a government qualified products list, QPL-25732.
- Polymer
- Nitrile (NBR)petroleum hydraulic fluid
- Durometer
- 70 to 80the Parker® compound's band
- Current drawing
- SAE-AS28775A2025-02-08
- QPL
- Yes, QPL-25732government, DLA QPD
Specification: documents, status, material
| Item | Value | Source |
|---|---|---|
| MIL document | MIL-PRF-25732 (= MIL-P-25732 = MIL-DTL-25732): Inactive for new design, revision E, 2024-03-08 | DLA ASSIST ident 18115, read 2026-09-24 |
| SAE material document | SAE-AMS-P-25732: Revised, current AMSP25732A, 2003-08-05 | SAE Mobilus, read 2026-09-24 |
| MS drawing | MS28775: superseded in DoD use by SAE-AS28775 (adopted 2000-09-29); status of the MS record: ask with the quote | DLA ASSIST adoption notice |
| Current drawing | SAE-AS28775, Packing, Preformed, MS28775 O-ring: current AS28775A, 2025-02-08 | SAE Mobilus, read 2026-09-24 |
| Base polymer | Nitrile (NBR) | document titles |
| Durometer | Parker ORD 5700 (2021) Table 8-4 lists its compound, N0304-75, in the 70 to 80 band; confirm the durometer against your print | Parker ORD 5700 (2021) |
| Service temperature | The MIL title and the SAE title print different upper limits, so we cite the governing document and quote no figure | the governing document |
| Slash sheets / classes | None; one document, one drawing | DLA ASSIST and SAE Mobilus, read 2026-09-24 |
| Boss variant | None in this family; the boss gasket is MS28778 / AS28778 on AMS-P-5510 | DLA ASSIST and SAE Mobilus; Parker ORD 5700 (2021) Table 8-3 |
| QPL | Yes, government: QPL-25732 in DLA's Qualified Products Database (QPL-25732-18 Amendment 3 seen, 2006); ask with the quote for the current list | DLA QPD; QPL-25732-18 Amd 3 |
| Service | Petroleum hydraulic fluid (the document title); Parker ORD 5700 (2021) Table 8-3 lists MIL-H-5606 beside it | document title; Parker ORD 5700 (2021) |
| Compounds manufacturers pair with this document | Parker ORD 5700 (2021) Table 8-3 and Table 8-4 pair N0304-75 with MIL-DTL-25732 and AMS-P-25732, noting the MS28775 series; the 2006 QPL amendment lists the same compound | Parker ORD 5700 (2021); QPL-25732-18 Amd 3 |
Status strings are quoted as DLA ASSIST and SAE Mobilus print them (Canceled is ASSIST's spelling; Inactive means inactive for new design; Withdrawn is SAE's word). Conquest Seal is a distributor and is not itself listed on any qualified products list.
Designator to AS568 size
Standard three-digit AS568 sizes: MS28775-XXX and AS28775-XXX are the AS568-XXX size, per the manufacturers' cross-references. There is no two-digit boss variant in this family; the boss gasket callout is MS28778. The dash never changes the material.
| MS28775 | AS28775 | AS568 dash | ID in | W in | ID mm | W mm |
|---|---|---|---|---|---|---|
| MS28775-006 | AS28775-006 | AS568-006 | 0.114 | 0.070 | 2.90 | 1.78 |
| MS28775-010 | AS28775-010 | AS568-010 | 0.239 | 0.070 | 6.07 | 1.78 |
| MS28775-012 | AS28775-012 | AS568-012 | 0.364 | 0.070 | 9.25 | 1.78 |
| MS28775-112 | AS28775-112 | AS568-112 | 0.487 | 0.103 | 12.37 | 2.62 |
| MS28775-114 | AS28775-114 | AS568-114 | 0.612 | 0.103 | 15.54 | 2.62 |
| MS28775-116 | AS28775-116 | AS568-116 | 0.737 | 0.103 | 18.72 | 2.62 |
| MS28775-210 | AS28775-210 | AS568-210 | 0.734 | 0.139 | 18.64 | 3.53 |
| MS28775-214 | AS28775-214 | AS568-214 | 0.984 | 0.139 | 24.99 | 3.53 |
| MS28775-222 | AS28775-222 | AS568-222 | 1.484 | 0.139 | 37.69 | 3.53 |
| MS28775-325 | AS28775-325 | AS568-325 | 1.475 | 0.210 | 37.47 | 5.33 |
Millimeter values are converted from the inch table. The dash is a size lookup and never a material; the same dash on another family on the mil-spec hub is the same size in a different document. Full chart: AS568 size chart.
Where the documents stand
MIL-P-25732 is one government record that changed prefix twice, to MIL-DTL-25732 and then MIL-PRF-25732; its revision E is dated 2024-03-08 and DLA ASSIST lists it as inactive for new design. The 2006 amendment to QPL-25732 records that the document was declared inactive for new design effective 1989-11-15 and superseded for new design by MIL-P-83461, the improved-performance hydraulic nitrile. SAE issued its parallel material document, AMS-P-25732, revised to A in 2003. The MS28775 drawing was adopted into DoD use as SAE-AS28775 in 2000, and SAE revised it to A on 2025-02-08 under the title Packing, Preformed, MS28775 O-ring.
The practical reading: MS28775-XXX is still a live callout on drawings and orders, the current drawing is AS28775, and the material document is still maintained and still carries a qualified products list. For a new design the government intent since 1989 has been M83461/1, which is the same nitrile family with improved performance. If the print says MS28775, quote MS28775; do not substitute.
The base polymer
The polymer behind this family is nitrile (NBR). For the 25732 family the MIL title and the SAE title print different upper limits, so this page names the governing document and quotes no temperature figure; the compound sheet for the qualified grade governs.
Material page: Nitrile (NBR) O-rings. Temperature ranges by family: O-ring temperature ranges.
How we quote this family
Send the designator as printed, MS28775-XXX or AS28775-XXX, with the dash, the quantity and the certification the order needs. The quote reads: supplied against MIL-PRF-25732 and the AS28775 drawing, in the nitrile compound the document calls for, made by QPL-listed manufacturers, with a certificate of conformance and lot traceability. If the print names a compound number, include it and we quote that compound. Every dash on this page links to its size page so you can confirm the dimensions before you send the request.
Related pages
Other families: M83461/1, M83248/1 and M83248/2, M83485/1, M25988/1, /2, /3 and /4, MS29513 and MS29512, NAS1611 and NAS1612, AS3582, AS9386 and AS9385, AS3209 and AS3208.
Frequently asked
Is MIL-P-25732 still active, and what replaced it?
MIL-P-25732 is the same document as MIL-PRF-25732, and DLA ASSIST lists it as inactive for new design at revision E of 2024-03-08. Inactive is not cancelled: the document is maintained, procurable and still carries QPL-25732. The 2006 QPL amendment records that it was superseded for new design by MIL-P-83461 back in 1989, and the MS28775 drawing's SAE successor is SAE-AS28775A. SAE's parallel material document is AMS-P-25732A.
What compound does MS28775 call for?
A nitrile (NBR) compound qualified to MIL-PRF-25732, the petroleum hydraulic fluid resistant packing document. Parker ORD 5700 (2021) pairs its N0304-75 with MIL-DTL-25732 and AMS-P-25732 and notes the MS28775 series beside it; other listed manufacturers have their own qualified compounds. We quote the part in the compound the document calls for and name the manufacturer on the certification.
Which mil-spec O-ring is the nitrile for petroleum hydraulic fluid?
MS28775 is the petroleum hydraulic nitrile family, and Parker ORD 5700 (2021) lists its compound, N0304-75, in the 70 to 80 hardness band; confirm the durometer against your print. M83461/1 is the improved-performance nitrile in the same service, and Parker lists its N0756-75 in the same band. The nitrile for hydrocarbon fuel rather than hydraulic fluid is MS29513.
What O-ring should I use for MIL-H-5606 hydraulic fluid?
The MS28775 family is the petroleum hydraulic fluid nitrile, and Parker ORD 5700 (2021) lists MIL-H-5606 beside the MIL-DTL-25732 line in its specification table. M83461/1 covers the same fluid with the improved-performance document. The print or the system specification decides which family; send it over and we quote that one.
What is the AS568 equivalent of MS28775-214?
The -214 is already the AS568 dash. MS28775-214 is the AS568-214 size, 0.984 in inside diameter and 0.139 in cross-section, in the MIL-PRF-25732 nitrile. AS568 fixes the size and MIL-PRF-25732 fixes the material.
What is M83461/1 and how does it differ from MS28775?
Both are nitrile O-rings for petroleum hydraulic fluid in the same AS568 sizes. MS28775 is made to MIL-PRF-25732; M83461/1 is made to MIL-P-83461/1, the improved-performance document that the 1989 notice named as the new-design replacement, now superseded by SAE-AMS-P-83461 and SAE-AS83461/1. They are different documents and different compounds, so quote the one the print names.
Related guides
Sources
DLA ASSIST document details, ident 18115 (MIL-PRF-25732), read 2026-09-24; SAE Mobilus: AS28775A (2025-02-08), AMSP25732A (2003-08-05), read 2026-09-24; QPL-25732-18 Amendment 3, 2006-02-16 (US Air Force), for the list's existence and the 1989 inactivation note; Parker O-Ring Handbook ORD 5700 (2021), Tables 8-3 and 8-4, for the compound pairing; AS568 dimensions from this site's size chart. Facts are stated in our own words and our own arrangement; no standard's text or table and no manufacturer's cross-reference table is reproduced. Compound pairings are the named manufacturer's published statements, not qualified products list entries.
Parker is a trademark of Parker Hannifin Corporation. No affiliation or endorsement is implied.
Need MS28775 with certification?
Send the designator as the print reads it, the dash, the quantity and the paperwork the order needs. A Conquest representative replies with the part quoted against the document.
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