Description

Someca 20 D, 25 D 1966 Parts Catalog

Ordering the wrong part for a 1960s tractor doesn’t cost you just the price of the part — it costs you the three days you spend waiting for the replacement to arrive, plus the labor of tearing down something you didn’t need to touch. I’ve seen guys order a fuel pump for a Someca 20 D and get a later revision that didn’t match the mounting bracket because they used a third-party cross-reference that was off by one digit. That stops here. This is the original Someca 20 D, 25 D 1966 Parts Catalog — 276 pages of factory-issued part numbers, exploded diagrams, and revision notes straight from January 1966. No reprints, no aftermarket guesswork.

Every page in this catalog comes from the second printing (2ème TIRAGE, 1966) of the original master catalog. The first page carries a warning I want you to read: “Pour toutes commandes de pièces de rechange utilisez les références inscrites dans la colonne NOUVEAUX NUMÉROS” — use the new numbers column. That’s the kind of detail that saves you a head-scratcher when you’re holding a part that looks right but has a superseded number. Look at page 1 of the PDF: it tells you this replaces reference 10.403 and to always order by the new number if there’s a discrepancy.

Engine and Fuel System – 10 Plates Covering Injection and Distribution

Inside the ENSEMBLE MOTEUR section you get PLANCHE 1 through PLANCHE 6 for the block, cylinder head, crankshaft, connecting rods, and the half-compression control. That half-compression control is specific to these tractors — you won’t find it outlined like this in any general ag manual. The fuel group runs from PLANCHE 7 through PLANCHE 24 and includes separate plates for the injection pump (PLANCHE 13), two different fuel feed pump models (nos. 755.758 and 763.566), and the pneumatic speed regulators (EP/M 60 A and EP/MN 80 AA). If you’re rebuilding the injection system on a 25 D, you need to see PLANCHE 13 to identify the right plunger and delivery valve assembly.

Hydraulic Lift Group – 16 Plates for the Relevage Hydraulique

The hydraulic lift on later 20 D and 25 D tractors used a controlled-force system. PLANCHE 54 through PLANCHE 58 B cover the lift control assembly, reservoir, distributor, cylinders, and the three-point hitch attachment. PLANCHE 56B and 56 bis specifically cover the controlled-force distributor and its servo controls. These plates separate the standard system from the effort-controlled version, so you won’t accidentally order a valve spool that doesn’t match your serial number range. If your tractor won’t lift and you’re chasing a worn valve, this is the catalog that shows you the exact seal kit dimensions.

Brakes, Steering, and Chassis – Factory Exploded Views

Brakes get two plates (PLANCHE 40–41) — pedal and hand brake commands. Steering takes up PLANCHE 45 through 49, including the front axle spindles and wheel assemblies (PLANCHE 47 and 48). The chassis plate (PLANCHE 42) shows the full frame and engine suspension brackets. None of these parts are listed with generic descriptions like “bushing, steering”; each one has a factory number that matches the Someca bin system. For a tractor that’s been sitting for 40 years, you need to know if the tie rod ends on your 20 D are the same as the 25 D — the catalog shows you the difference in the lever arms on PLANCHE 46 A.

Why Factory Parts Numbers Beat Aftermarket Cross-References

I’ve watched a shop burn two hours trying to match a water pump from a universal catalog to a 1966 Someca 25 D. The problem: that tractor used two different water pumps (no. 561.514 and no. 566.997, PLANCHE 28 and 29). You order the wrong one and the bolt pattern is 1/8″ off. The aftermarket book says “fits Someca 20/25 D” — which is true if you like drilling bell housings. This catalog calls out the specific pump model on each plate, along with the impeller and seal part numbers. The same goes for the fuel filter (PLANCHE 11) and the oil pressure regulator (PLANCHE 26). You aren’t guessing.

For anyone working on these tractors, I’d also check the Someca T.P.S. 1962 Parts Catalog if you have an earlier model, or the SOMECA SOM 55 Parts Catalog for the larger frame tractors. If you need the 35 series, the SOMECA SOM.35 Parts Catalog covers that chassis.

Who Needs This Catalog?

If you own a 20 D or a 25 D built in the mid‑1960s, and you plan to restore, repair, or maintain it yourself, you need this catalog on your workbench. Not a scanned recast from a third party — this is the original factory print, 276 pages, with the official Someca part numbering and revision history. It’s also useful for dealers or salvage yards that need to verify parts pulled from donor tractors. The language is French, but the diagrams and numbers are universal. Automotive Industry Overview provides background on historical tractor manufacturing if you want context, but for the work at hand the catalog is all you need.

Copy it to a tablet or print it out. Circle the parts numbers on the plates before you call the dealer. You’ll save yourself the headache of returns and the downtime of waiting for a replacement that might not fit. Automotive Industry Overview

Frequently Asked Questions

Does this parts catalog include torque specifications or repair procedures?

No. This is a parts catalog — it lists every component with its factory part number, and shows them in exploded views so you can identify what you need. It doesn’t include step-by-step overhaul instructions or torque values. That’s covered by the shop manual, which is separate.

Will the part numbers work for a 1965 20 D?

Mostly yes, but check the revision notes on page 1. The catalog was issued in January 1966 and supersedes reference 10.403. If your tractor was built before the second printing, some numbers may have changed. Always use the “NOUVEAUX NUMÉROS” column if it’s populated.

Are the diagrams clear enough to identify individual springs and shims?

Yes. The plates are dimensionally drawn and each part is circled with a leader line to the number. For example, PLANCHE 31 shows the clutch release bearing and lever assembly with eight separate callouts — you won’t mistake the release fork spring for the pedal return spring.

Can I order parts directly from this catalog at a dealership?

Most Someca dealers still reference these factory numbers, but the catalog is a 1966 issue. Check with your dealer for current stock or supersessions. Having the official Someca number on hand gives them a starting point instead of you describing parts over the phone.

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