The Seat,valve, cataloged under National Stock Number 4820-01-253-4637, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division. Government technical data includes 14 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 2 items share a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-253-4637 |
| Primary Part Number | 035-16231 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division |
| Status | ACTIVE |
| Flange Seat to Disk End Height | 0.094 INCHES NOMINAL IN |
| Flange Diameter | 0.672 INCHES NOMINAL IN |
| Thread Length | 0.344 INCHES NOMINAL SINGLE THREADED PORTION IN |
| Hardness Rating | 40.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM OVERALL |
| Body Stepped Inside Diameter | 0.201 INCHES NOMINAL THIRD STEP IN |
| Body Stepped Inside Diameter | 0.313 INCHES NOMINAL FIRST STEP IN |
| Body Stepped Inside Diameter | 0.316 INCHES NOMINAL SECOND STEP IN |
| Style Designator | THREADED FLANGED |
| Nominal Thread Size | 0.500 INCHES SINGLE THREADED PORTION IN |
| Under Flange Height | 0.594 INCHES NOMINAL IN |
| Thread Class | 3A SINGLE THREADED PORTION A |
| Material | STEEL COMP 4140 OVERALL |
| Thread Series Designator | UNF SINGLE THREADED PORTION |
| Seating Surface Shape | FLAT |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| 35-16231 | Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division (USA) |
| 035-16231 PRIMARY | Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division (USA) |
| Reference | Meaning |
|---|---|
| 35-16231Z | C/1 Advisory reference — outside the item-of-supply concept Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division |
| 25-8153-W | D/9 Drawing number reference only Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division |
NSN 4820-01-253-4637 is a Seat,valve, manufactured by Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-253-4637 has 2 manufacturer part numbers on file: 35-16231 (Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division), 035-16231 (Parker-Hannifin Corporation Dba Pneutronics Div Hydraulic Pump Division).
2 possible matches (shared part number, not a government interchangeability claim): 4820-01-253-4638, 3040-01-299-4117. Verify interchangeability with system specifications before substitution.
Key specifications for 035-16231: Flange Seat to Disk End Height: 0.094 INCHES NOMINAL IN; Flange Diameter: 0.672 INCHES NOMINAL IN; Thread Length: 0.344 INCHES NOMINAL SINGLE THREADED PORTION IN; Hardness Rating: 40.0 ROCKWELL C MINIMUM AND 45.0 ROCKWELL C MAXIMUM OVERALL. 14 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.