System-Matched Supply — Oil pump and overhaul components verified against engine serial variants before dispatch.
Technical Specifications
| Parameter |
Value |
| Part Number |
16851-35012 |
| Product Type |
Oil Pump |
| Cross-Reference |
16851-35010, 15841-35010, 16851-35014, 1685135010, 1685135012, 1685135014, 1584135010 (reference only) |
| Machine Fitment |
Kubota B7300HSD, B7400HSD, BX1500D–BX25DLB-1, G1700–G6200H, GR2100–GR2120B-2, RTV900/RTV-X900 series, KX018-4, KX41-3, U15, U17, ZD/ZG/ZP series mowers |
| Material |
Hardened alloy steel (HRC 58–62) |
| Seal Type |
Triple-lip nitrile rubber |
| Operating Temperature |
Up to 120 °C |
| Pressure Rating |
Up to 6 bar |
| Dimensional Tolerance |
±0.02 mm |
| Surface Finish |
ISO 1302 Ra 0.8 μm |
| Warranty |
3–12 months against manufacturing defects |
| Condition |
New Aftermarket |
| MOQ |
1 piece |
Application Suitability
| Engine System |
Related Components |
| Lubrication circuit — D722 / D902 main pressure supply |
Overhaul gasket kit, main and con-rod bearings, oil pickup screen |
| Post-rebuild break-in oil delivery |
Piston ring set matched to bore condition, crankshaft bearings at correct grade |
| High-shear agricultural and compact excavator duty |
Relief valve assembly, oil cooler seals, timing cover gasket |
| Utility vehicle fleet maintenance cycle |
Oil filter, sump drain plug washer, camshaft journal bearing shells |
Why the Same Oil Pump Part Number Covers Multiple Engine Builds
The correct oil pump for Kubota D722 / D902 engines depends on the serial prefix and previous rebuild history, not just the base number.
I have watched a mini excavator in Kalimantan sit dismantled for a week because the replacement oil pump for Kubota engine rebuild kits arrived with porting suited to an earlier D722-E2B variant, while the block on the bench was a D902-E3B with revised internal galleries. The part number looked identical on the cross-reference sheet. The gear engagement depth and suction port orientation were different enough to cause starvation at the camshaft journals within the first hundred hours [NEED_CITE: Kubota D-series engine serial variant identification for lubrication components]. This oil pump (cross-reference 16851-35012) replaces several superseded numbers across production generations, and each engine serial variant demands a slightly different internal configuration.
Lubrication Circuit Position and Adjacent Components
An oil pump for Kubota engine rebuild sits at the beginning of the entire pressure circuit. Its output feeds the main bearings first, then branches to the con-rod journals and camshaft. If the preceding overhaul left bearing clearances wider than specification, even a pump delivering full rated flow will show low pressure on the gauge. This is not a pump fault — it is a system mismatch. We match the oil pump supply with the bearing grade and oversize that the crankshaft actually requires after its last regrind, rather than treating the pump as an isolated line item.
Engine Serial Variants and Rebuild History Verification
Across the D722 and D902 families, internal porting and gear engagement depth shifted between the E2B, E3B, and later designations. A machine that has already been through one rebuild may also have a crankshaft ground to 0.25 or 0.50 oversize, which changes the bearing shell thickness needed and indirectly affects the oil pressure the pump must sustain [NEED_CITE: crankshaft oversize grades and bearing clearance effects on oil pressure in small diesel engines]. Confirming the full engine serial prefix — for example D722-E3B-LCN-2 — before dispatch prevents the situation where the pump physically bolts on but delivers oil to galleries configured for an earlier variant.
Specification Interpretation for Lubrication Demands
The hardened alloy steel gears at HRC 58–62 resist the abrasive wear that contaminated break-in oil accelerates during the first fifty hours after a rebuild. The triple-lip nitrile seal retains pressure at the drive shaft interface up to 120 °C, which matters when a zero-turn mower operates in direct tropical sun with hydraulic oil temperatures already elevated. The ±0.02 mm dimensional tolerance on gear-to-housing clearance keeps volumetric efficiency stable, so the oil pump for Kubota engine rebuild applications maintains pressure across the RPM range rather than bleeding off at idle. Surface finish at ISO 1302 Ra 0.8 μm on the gear faces reduces the initial wear particles that would otherwise circulate through fresh bearing shells during break-in [NEED_CITE: gear pump surface finish standards for engine lubrication service].
The Cost of Skipping Root-Cause Diagnosis
Replacing an oil pump without investigating why the previous unit failed early is the most common reason for repeat teardowns. Blocked pickup screens, incorrect oil viscosity specified for the ambient conditions, or a worn relief valve spring will destroy a new pump just as quickly as the old one. I have seen repair centres in the Philippines invoice a customer for a second overhaul because the diagnosis stopped at the pump itself and never traced upstream to a collapsed suction hose [NEED_CITE: common root causes of premature oil pump failure in compact diesel engines]. The oil pump is the symptom location as often as it is the fault location.
Why Source This Component Through XUNPO
Self-produced and qualified-sourced lines carry the same warranty terms, so an oil pump ordered alongside an overhaul gasket kit and bearing set arrives under one account and one claim path. Eight product categories mean the timing cover gasket, sump plug washer, and oil filter ship in the same consignment as the pump. The Guangzhou warehouse holds stock on fast-failure items like this unit for immediate dispatch. Part identification is confirmed from a part number, machine model, photograph, or nameplate image before anything ships. Cross-reference verification covers superseded and alternate numbers such as 16851-35010 and 15841-35010 to catch production-generation mismatches. Samples are available for fitment confirmation before a fleet operator commits to a bulk order across multiple machines.
Documentation & Verification
- Commercial invoice listing 16851-35012 with cross-reference numbers marked reference only
- Part compatibility sheet mapping engine serial prefixes to correct pump variant
- Dimensional inspection record covering gear clearance and port spacing
- Warranty terms aligned to duty cycle severity and application type
- Packing photographs showing anti-static foam cushioning before crate closure
- HS code and customs documentation prepared for Southeast Asian import corridors
Installation & Rebuild Sequence
- Flush all oil galleries and replace the pickup screen before installing the oil pump for Kubota engine rebuild applications
- Verify crankshaft bearing grade matches the pump output pressure at expected idle RPM
- Torque mounting fasteners to the engine manual sequence to avoid housing distortion
- Prime the pump cavity with clean assembly oil before the first crank to prevent dry start scoring
- Monitor oil pressure gauge for the first thirty minutes and confirm relief valve opens at specification
- Re-check sump level after the initial run as galleries fill and air purges from the circuit
Request a System-Matched Quotation
Provide the full engine serial prefix, any known crankshaft regrind history, and the machine model to confirm which variant of this oil pump suits your rebuild. If the nameplate is worn, a photograph of the block casting number or the old pump drive face is enough for identification. We return a matched component list covering the pump, seals, and adjacent overhaul items in one quotation.
Frequently Asked Questions
Q: What other lubrication components should I replace during a D722 or D902 overhaul?
A: Alongside the oil pump, replace the pickup screen, relief valve spring, timing cover gasket, and all crankshaft and camshaft bearing shells. If the previous rebuild used non-standard oversize bearings, confirm the current crankshaft journal diameter before ordering to avoid clearance mismatch.
Q: How do engine serial variants affect oil pump fitment on Kubota engines?
A: Internal port orientation, gear engagement depth, and suction port position changed between D722-E2B, D902-E3B, and subsequent designations. Providing the full serial prefix ensures the correct variant ships, since the base part number alone covers multiple configurations that are not physically interchangeable.
Q: My previous oil pump failed early — how do I find the real cause before rebuilding again?
A: Inspect the pickup screen for blockage, test the relief valve spring for fatigue, and check oil viscosity against the ambient operating range. Collapsed suction hoses and incorrect filter bypass settings also cause starvation that appears as pump failure.
Q: Can I order this oil pump together with an overhaul gasket kit and matched bearings?
A: Yes. We supply the pump alongside gasket sets, piston rings, and bearing shells graded to the crankshaft's actual condition after any previous regrind, consolidating everything into a single shipment under one warranty.
Q: How do I confirm the correct bearing grade if the crankshaft was reground previously?
A: Measure the main and con-rod journal diameters with a micrometer and compare against the engine manual's oversize chart. Ordering bearings without this check risks pairing a standard-grade shell with a reground journal, causing either excessive clearance or seizure at startup.
