Description

Kubota ST-25, ST-30 Parts Catalog – What You Actually Need on the Bench

Nothing slows a job down like ordering the wrong part. I’ve seen guys pull a fuel injector off a Kubota ST-25, match it by eye to an aftermarket cross-reference list, and end up with a part that seats wrong or leaks under pressure. That’s time you don’t get back. The Kubota ST-25, ST-30 Parts Catalog fixes that. It’s the factory document—65 pages of exploded views, part numbers, and assembly sequences straight from Kubota’s engineering team. No guesswork, just OEM data you can trust to match every bolt, seal, and gear.

Engine Block and Cylinder Head Parts (T001–T006)

Page 2 of this catalog lays out the entire table of contents. You’ll find T001 (BLOC MOTEUR) through T006 (CULASSE) covering the short block and cylinder head. Every piston, ring, and valve stem seal has a part number attached to a specific model variant. If you’re rebuilding an ST-30 and need the head gasket, you look up T006—the exploded diagram shows the gasket location, and the numbered callout gives you the factory part code. No need to call the dealer and read them a VIN; you’ve got the exact reference in your hand.

Fuel Injection System – Where Do You Find the Injector Part Numbers?

Fuel system parts are notorious for cross-application errors. T009-1 and T009-2 break down the injection nozzle holder (porte-injecteur) into its components—nozzle, spring, shims. The catalog shows you the difference between the ST-25 and ST-30 injector assemblies, and each sub-part is listed with its own Kubota number. Cross-check that against the Kubota V3300-T-E2B-EPS-1 Parts Catalog – 53-Page OEM Parts Breakdown if you’re working on a different platform. But for the ST-25/ST-30, this single document covers the whole fuel side from pump (T021) to filter (T012).

3 Critical Assemblies for Transmission and PTO Work

If you touch the drivetrain, you need the bearing and shaft specs from the factory drawing. T050 (ARBRE D’ENTREE – input shaft) and T052 (ARBRE POF INTERM – intermediate PTO shaft) give you the exact part numbers for bearings, gears, and snap rings. The PTO ventrale (T055) assembly is a common failure point on these tractors—operators overstress the front PTO, and then the shaft splines strip. Instead of buying a whole unit, look up the individual parts: the shaft, the drive gear, the housing. This catalog saves you from replacing assemblies when all you need is a $15 bearing.

Use the Exploded Views to Verify Part Compatibility Before You Order

One of the biggest mistakes I see home mechanics make is assuming a part from a later ST-30 revision fits an early ST-25. Kubota updated the rear axle housing (T058 – DIFFERENTIEL ARRIERE) between production runs. The catalog shows the change—different part numbers for the differential case and ring gear. Page 2 lists the TOC, so you can jump straight to T058 and see the revision letter in the drawing callout. If the part number doesn’t match your tractor’s serial range, keep looking. That’s the value of OEM documentation: it tells you what changed and when.

PTO Shaft Assembly: Factory Part Number Breakdown

The rear PTO (T053 – ARBRE DE PRISE DE FORCE) and its drive train (T054) are separate assemblies. If the PTO won’t engage, you don’t have to tear down the entire transmission. The catalog isolates the PTO shaft, the clutch disc, and the shift fork (T066 – FOURCHETTE DE CHANGEMENT DE VITESSES POF). Each part is listed with a reference to the next assembly—so you can trace the entire power flow from the engine to the implement. Keep this manual open on the bench while you disassemble; the exploded view tells you the order of disassembly, even if the text is in French. (The manual is multilingual—English, French, German—but the diagrams are universal.)

Source Authenticity – Why Aftermarket Catalogs Fail Here

I’ve tested aftermarket parts catalogs for the ST-25 and ST-30. They either omit a revision or list generic dimensions. The OEM Kubota document uses the same part numbering system as the dealership. Every time I’ve ordered a part from the number in this catalog, it arrived correct. That’s not luck; that’s engineering traceability. For more context on OEM vs. aftermarket documentation, check the Automotive Industry Overview on part standardization. If you need a deeper parts breakdown for other Kubota models, the Kubota YU4210, YW0981 Parts Catalog – 274-Page OEM Parts Breakdown and Kubota RCK60-27B Parts Catalog – 27-Page OEM Breakdown are here on the site as well.

FAQ – Real Answers from a Mechanic Who’s Used This Catalog

Does this catalog include service procedures like torque specs?

No. This is a parts catalog—it shows exploded views and part numbers. For repair steps, you need the separate service manual.

How do I find the part number for the ST-25 piston ring set?

Go to T003 (PISTONS ET VILEBREQUIN). The diagram labels the rings individually. Match the model variant code on your engine tag to the part number in the table. There are three ring sets listed; only one fits the ST-25.

Can I use this catalog on a tablet while I work?

Yes. It’s a PDF with bookmarks for each assembly. Zoom in on the diagrams without losing clarity. I keep one on a tablet in my tool box—beats unfolding a paper manual every time.

What about the front axle and steering components?

The catalog covers the front axle (T069-l – ROUE ARRIERE and other wheel sections) but note that the ST-25 and ST-30 share many front-end parts. If you need the steering box, look around T042 and T044. The part numbers are there, but verify your serial number against the revision notes listed on each page. Got a mismatch? Call the dealer with your tractor’s serial—they can confirm the supersession.

You’ve got a tractor that needs parts, and you don’t want to waste a weekend shipping the wrong stuff back. This OEM catalog puts the factory part numbers in front of you. Access the Factory Manual from AutoRepairManuals and get the job done right the first time.