Fleetguard · HF Hydraulic · inline line
HF6321 filter element: specifications & equivalents
The HF6321 is a Fleetguard inline-line hydraulic filter element, sized 105 × 309 mm OD × length (ID 50 mm), rated at 80 µm absolute (80 µm at β75(c) per ISO 16889). Verify against the current manufacturer data sheet before ordering.
Envelope OD × L 105 × 309 mm
Inside diameter 50 mm
Filtration rating 80 µm abs.
Beta rating 80 µm at β75(c) per ISO 16889
Collapse / burst 3 bar
Line type inline
Catalog verified. Parameters extracted from the manufacturer’s electronic
catalog / official interchange document and checked 2026-09-28. Confidence score 0.90.
Specifications and cross-references are taken from the Fleetguard online catalog API. Where both TWA and Beta ratings are published the conventions differ — verify cleanliness targets, collapse rating and seal configuration against the current Fleetguard data sheet before ordering.
Specification table
| Parameter | Value |
|---|---|
| Filter type | inline line |
| Filtration rating | 80 µm |
| Rating basis | absolute |
| Beta ratio | 80 µm at β75(c) per ISO 16889 |
| Outside diameter OD | 105 mm |
| Inside diameter ID | 50 mm |
| Length | 309 mm |
| End caps | open-ended cartridge element |
| Rated flow | 50 L/min |
| Collapse / burst pressure | 3 bar |
| Integral bypass valve | none (housing/valve-dependent) |
| Manufacturer part no. | HF6321 |
| Source catalog | Cummins Filtration / Fleetguard: Fleetguard online product catalog (fleetguard.com) |
| Last verified | 2026-09-28 |
Sources: Cummins Filtration / Fleetguard — Fleetguard online product catalog (fleetguard.com) — accessed 2026-09-28.
Fleetguard® and all model designations are trademarks of their respective owners, used here for identification only — ElementRef is an independent reference site, not an authorized Fleetguard distributor.
Dimensions & series range
| Outside diameter | 105 mm (4.134 in) |
| Inside diameter | 50 mm (1.969 in) |
| Overall length | 309 mm (12.165 in) |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
|
↔ 2200100 page in verification queue | UFI | partial | Fleetguard's online catalog lists 2200100 as an interchange for HF6321. Envelope cross-reference; verify micron grade, collapse rating and seal configuration before substituting. |
|
↔ 78253660 page in verification queue | UFI | partial | Fleetguard's online catalog lists 78253660 as an interchange for HF6321. Envelope cross-reference; verify micron grade, collapse rating and seal configuration before substituting. |
|
↔ 8253660 page in verification queue | UFI | partial | Fleetguard's online catalog lists 8253660 as an interchange for HF6321. Envelope cross-reference; verify micron grade, collapse rating and seal configuration before substituting. |
|
↔ AZH021 page in verification queue | Aftermarket | partial | Fleetguard's online catalog lists AZH021 as an interchange for HF6321. Envelope cross-reference; verify micron grade, collapse rating and seal configuration before substituting. |
|
↔ C4666 page in verification queue | Aftermarket | partial | Fleetguard's online catalog lists C4666 as an interchange for HF6321. Envelope cross-reference; verify micron grade, collapse rating and seal configuration before substituting. |
|
↔ FH3232 page in verification queue | Aftermarket | partial | Fleetguard's online catalog lists FH3232 as an interchange for HF6321. Envelope cross-reference; verify micron grade, collapse rating and seal configuration before substituting. |
|
↔ HEM6049 page in verification queue | Aftermarket | partial | Fleetguard's online catalog lists HEM6049 as an interchange for HF6321. Envelope cross-reference; verify micron grade, collapse rating and seal configuration before substituting. |
|
↔ HF0632100 page in verification queue | Fleetguard | partial | Fleetguard's online catalog lists HF0632100 as an interchange for HF6321. Envelope cross-reference; verify micron grade, collapse rating and seal configuration before substituting. |
|
↔ IF5120 page in verification queue | Aftermarket | partial | Fleetguard's online catalog lists IF5120 as an interchange for HF6321. Envelope cross-reference; verify micron grade, collapse rating and seal configuration before substituting. |
|
↔ R5120 page in verification queue | Aftermarket | partial | Fleetguard's online catalog lists R5120 as an interchange for HF6321. Envelope cross-reference; verify micron grade, collapse rating and seal configuration before substituting. |
|
↔ Z274 page in verification queue | Aftermarket | partial | Fleetguard's online catalog lists Z274 as an interchange for HF6321. Envelope cross-reference; verify micron grade, collapse rating and seal configuration before substituting. |
Interchange levels: full catalog-confirmed drop-in · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the HF6321 model number is decoded
- HF6321Fleetguard HF-series hydraulic cartridge element part number.
- 309 mmOverall height.
- 105 mmLargest outside diameter.
- 50 mmLargest end inside diameter.
- 80 µm at β75(c) per ISO 16889Published efficiency ratings.
Typical equipment & applications
- Construction, agricultural and industrial hydraulic circuits
- Mobile-equipment hydraulic return and pressure lines
Selection pitfalls — read before you substitute
- “10 µm nominal” and “12 µm at β1000” can describe the very same media — one is reported at β≥200, the other at β≥1000 per ISO 16889. Compare ratings at the same Beta test point, not just the printed micron number.
- Nitrile (NBR) seals are standard for mineral hydraulic oil but fail early in some phosphate-ester fluids and at sustained high temperature; verify seal compound against the fluid data sheet (fluorocarbon/Viton executions may be required).
- End-cap geometry and the number/position of O-rings block interchange even when OD and length match — visually compare end caps before fitting, especially with aftermarket cartridges.
Frequently asked questions
What are the dimensions of the HF6321 filter element?
The published envelope is 105 mm OD × 309 mm length with a 50 mm inside diameter (4.134 × 12.165 in × 1.969 in ID). Confirm against the housing drawing before ordering.
What micron rating does HF6321 use?
This element is rated 80 µm absolute — 80 µm at β75(c) per ISO 16889. Always compare Beta ratings at the same test point: two brands may print different micron numbers for the same physical grade.
What replaces the HF6321 filter element?
11 partial match(es) requiring parameter review
How do I read the HF6321 part number?
See the designation decoder above: each segment of HF6321 encodes size, line type, filtration grade and media/collapse execution.
Is a same-envelope aftermarket element always a drop-in replacement?
No. Matching OD and length only proves the cartridge fits the bowl. End-cap style, seal compound, micron/Beta rating, collapse pressure and bypass configuration must also match; the table above tags every equivalent as full, partial or verify for exactly this reason.
How often should a hydraulic return-line element be replaced?
Replace at the housing manufacturer’s recommended differential-pressure setting (commonly signalled by a clogging indicator), or on a time-based service interval when no indicator is fitted — never wait for bypass to open continuously, because unfiltered oil then reaches the valves.
Other models in the HF Hydraulic series
All 2621 →Reviewed & verified by the ElementRef engineering desk against Cummins Filtration / Fleetguard on 2026-09-28. Read our editorial & correction policy.