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WIX Filters · 51xxx · return line

51799 filter element: specifications & equivalents

The 51799 is a WIX Filters return-line hydraulic filter element, built with enhanced cellulose media, sized 135.7 × 309.5 mm OD × length, rated at 19 µm class (β2 = 16, β20 = 33). Verify against the current manufacturer data sheet before ordering.

Envelope OD × L 135.7 × 309.5 mm
Filtration rating 19 µm nom.
Beta rating β 2 = 16, β20 = 33
Media Enhanced Cellulose
Thread M36x1.5
Collapse / burst 27.579 bar
Line type return
Catalog verified. Parameters extracted from the manufacturer’s electronic catalog / official interchange document and checked 2026-09-27. Confidence score 0.90.

Specification table

ParameterValue
Filter type return line
Media Enhanced Cellulose
Filtration rating 19 µm
Rating basis nominal
Beta ratio β2 = 16, β20 = 33
Outside diameter OD 135.7 mm
Length 309.5 mm
Thread / connection M36x1.5
End caps spin-on baseplate with attached gasket
Flow direction outside-in
Collapse / burst pressure 27.579 bar
Integral bypass valve opens at 2.137 bar
Seal material Nitrile (NBR)
Manufacturer part no. 51799
Source catalog WIX Filters (MANN+HUMMEL): WIX Filters online product catalog
Last verified2026-09-27

Sources: WIX Filters (MANN+HUMMEL) — WIX Filters online product catalog — accessed 2026-09-26.

WIX Filters® and all model designations are trademarks of their respective owners, used here for identification only — ElementRef is an independent reference site, not an authorized WIX Filters distributor.

Dimensions & series range

Outside diameter135.7 mm (5.343 in)
Overall length309.5 mm (12.185 in)

Cross references & equivalents

No catalog-verified cross references yet. This model is in the manual verification queue — request a verified equivalent.

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 51799 model number is decoded

  • 51799WIX hydraulic spin-on filter part number.
  • M36x1.5Mounting thread: M36x1.5 (spin-on baseplate).
  • Enhanced CelluloseFilter media: Enhanced Cellulose.

Typical equipment & applications

  • Mobile and industrial hydraulic return circuits
  • Construction and agricultural equipment
  • Heavy-duty transmission and torque-converter circuits

Selection pitfalls — read before you substitute

  • A return-line element is not a pressure-line element: return cartridges (BN4HC low-collapse) tolerate roughly 20 bar differential, while BH4HC pressure executions are rated to 210 bar. Installing a low-collapse element in a pressure housing can rupture the media on cold-start spikes.
  • This execution carries an integral bypass valve (opens at 2.137 bar). The same envelope also exists without it, relying on the housing valve. Mixing the two strategies changes cold-start protection — match what was installed originally.
  • “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 51799 filter element?
The published envelope is 135.7 mm OD × 309.5 mm length (5.343 × 12.185 in). Confirm against the housing drawing before ordering.
What micron rating does 51799 use?
This element is rated 19 µm (nominal class) — β2 = 16, β20 = 33. Always compare Beta ratings at the same test point: two brands may print different micron numbers for the same physical grade.
What replaces the 51799 filter element?
Cross references are being verified for this model — use the inquiry form and the engineering desk will confirm equivalents.
How do I read the 51799 part number?
See the designation decoder above: each segment of 51799 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 51xxx series

All 306 →
51089 74×144 mm · 32 µm 51096 115×183 mm · 5 µm 51097 114×231 mm · 10 µm 51098 115×227 mm · 23 µm 51113 129×228 mm · 5 µm 51116 94×198 mm · 11 µm 51119 115×229 mm · 23 µm 51120 94×198 mm · 9 µm 51127 88×235 mm · 32 µm 51134 152×216 mm · 10 µm

Reviewed & verified by the ElementRef engineering desk against WIX Filters (MANN+HUMMEL) on 2026-09-27. Read our editorial & correction policy.