Tractor pioneer remembered for his legacy


On Jan. 2, 2011, at the ripe old age of 96, Harold Brock from Waterloo, Iowa, died peacefully at his home. So what, you ask?


Well, because Harold Brock was in on the design phase of two of the most popular farm tractors in U.S. history — and for two completely different manufacturers.

Harold was born in Clarksburg, W.Va., but grew up in Detroit. In 1929, the 15-year-old boy left regular high school and enrolled in Ford Motor Company’s Trade and Apprentice School. This school, started by Henry Ford in 1916, was open to boys under 17 who were financially in need, qualifications possessed by Brock.

The school combined classroom learning with work in the Ford factory, for which the boys were paid. After graduation from the school, Brock went to work for Ford designing cars and trucks during the difficult 1930s.

Replacing animal power

Although halting production of the Fordson tractor in 1928, Henry Ford still hoped to replace animal power with machines and continued small-scale tractor experiments during the next decade, although it’s unlikely that Brock was involved with these.

In England, Harry Ferguson had developed his revolutionary hydraulic 3-point hitch and, after a failed venture to build the tractor by David Brown, he came to America hoping to find someone to manufacture his tractor.

Ferguson had been in contact with Ford during the 1920s, when he was pushing his “Duplex” hitch plow for the Fordson, and arranged through the Sherman brothers to demonstrate his one of the Ferguson-Brown tractors to Ford in the fall of 1938.


Some accounts say Harold Brock was present during the demonstration and witnessed the famous “handshake agreement” between Henry and Harry, while others don’t mention him as being there. In any event, Ford’s chief engineer, Larry Sheldrick, chose Brock, who at the time was in charge of car rear axle and transmission design, to be head of the small design team that would work on the new tractor with Ferguson’s engineers.

Priced right

Brock said later that Ford had told him that there were still 19 million draft animals on U.S. farms and he wanted a tractor that would cost no more than $580, the price of a team, harness and the 10 acres of ground needed to grow food for the team.

He was also instructed to design the tractor so that 14 of them could be shipped in a standard boxcar, thus holding down shipping costs.

After a couple of false starts, the job was done in record time, with the new Ford tractor with Ferguson System (Ford-Ferguson) being introduced to the public June 29, 1939 about nine months after the “handshake agreement.”


During the Second World War, Harold did design work on both the Sherman tank and the Ford jeep and, when the Ford and Ferguson tractor agreement was canceled in 1947, Ferguson asked him to work for him on the new Ferguson tractor.

Ford, however, promoted Brock to chief engineer of tractor design and he stayed with Ford Motor Company through the 1950s. Ford tractors introduced during this time included the famous “Red Belly” 8N, the Golden Jubilee, and the 600, 700, 800 and 900 series.

Transmission woes

In 1959, Brock’s boss insisted upon putting an automatic power-shift transmission into the new x01 series tractors. Brock refused to approve the transmission after testing the thing, believing it to be a defective design that would prove to be unreliable.

Brock wrote later, “I suggested that if they wanted to put the transmission into production they should obtain a new chief engineer. This they did. They fired me and subsequently put the transmission into production.”

Almost immediately he was approached by Deere & Company’s Waterloo Product Engineering Center to help with the design of the replacements for the venerable and popular line of two-cylinder tractors.

Meanwhile back at Ford, an automatic transmission called Select-O-Speed was made available on Ford tractors. The Select-O-Speed transmissions have been reviled as no good ever since, although some operators had no problems and love them.

Sour grapes

Brock later wrote (although it may have been a touch of sour grapes), “In the end, Ford had to shut down the factory for eighteen months and they fired the divisional manager (who had fired me) and his chief engineer. Ford management then called me and asked me to return, but… I declined.”

Tractor legacy

Brock was put in charge of the design group for the Deere 4020 tractor, which has influenced tractor design ever since. The model 4020 was introduced in 1963 and featured the first successful full powershift transmission, along with many other improvements. The John Deere 4020 remained in the Deere lineup until 1968 and many are still earning their keep on American farms today.

Harold Brock became Deere’s director of tractor research and later the firm’s first worldwide manager of product engineering. He retired in February of 1980, but served as a global consultant and in the 1980s, participated in a joint effort between Deere and Yanmar.

So, the reason we in the Rusty Iron hobby should remember Harold Brock is that he was the man who was instrumental in the design of two of the classic tractors of our time, the Ford-Ferguson 9N and the John Deere 4020.


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Sam Moore grew up on a family farm in Western Pennsylvania during the late 1930s and the 1940s. Although he left the farm in 1953, it never left him. He now lives near Salem, where he tinkers with a few old tractors, collects old farm literature, and writes about old machinery, farming practices and personal experiences for Farm and Dairy, as well as Farm Collector and Rural Heritage magazines. He has published one book about farm machinery, titled Implements for Farming with Horses and Mules.


  1. I dont have any personal expereince with ford select o speed tractors but our nieghbor had them the first of them was a little 801 powermaster ,they liked it very much!then they got a new 5000 ford in 1966 it also had a sos,witch they liked also then they got a new 1968 5000 it had an 8 speed standard ,i dont recall them having trouble with any of thier fords and these boy ran the shit out of everything they owned Charley Steyer owned a couple of them one was an older 6000 ford he told me not long ago the sos speeds were great if serviced correctly he told me band adjustments clean oil and filters were a must but if you did this they were good but that a 4000 sos rebuild witch he did himself cost him over 4800 dollars so beware!

  2. Ps charlie steyer said his old 6000 ford was one of his best tractors nouthing was better at filling the silos and over the years he has had a dozen or more fords ranging from 8 n up to 9600,a true ford fan,i think running a dairy farm for fifty plus years gives him the idea of what works best for him!,,,im sure theres jd fans too and ac oliver ect


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