Serial location guide
On the Massey Ferguson 135 and 35, and on the Detroit Ferguson TO tractors, the serial plate lives in the same neighborhood: on the instrument panel, below the steering wheel (on the Ferguson TO tractors, on the dash by the steering column). Finding it is the easy part. The trap is what comes next.
The MF 135 was built in Detroit, USA and in Coventry, England, and the two factories used completely different number systems. Detroit tractors from 1967 carry the famous 9A series (9A128141 and so on). Coventry tractors carry a plain number. Read a Detroit 9A tractor against the Coventry table — which is what several websites publish as "the" MF 135 table — and you will get a year that is wrong with total confidence.
The plate names Harry Ferguson Inc, Detroit. TO-20 and TO-30 shared one number run at the start: 60000 and under is a TO-20, 60001 and up a TO-30. The TO-35 continued the same run from 140001. Beware the English TE-20: it has its own series, also starting at 1 — the plate's city (Detroit vs Coventry) is the tell.
Coventry-built 35s (1957–1964) carry their number on the instrument panel too, and their castings carry a readable date code — month letter, day, and a year letter running F = 1957 through M = 1964 — a handy cross-check against the serial. A US-built 35 is a different story: it continues the Ferguson TO-35 series, so use the TO-35 decoder for a Detroit tractor.
Open the Massey Ferguson decoder
The decoder gives you the year. The kit gives you the rest of the check before money changes hands: serial-verification worksheets, the two-numbers check that catches swapped engines, year-split parts traps, and an inspection checklist for each family.
Included in the $39 Buyer's Check Kit