John Deere's Model D was produced over a span of 30 years, and enjoyed a production run longer than any other of its tractors. Of the nearly 200,000 units sold, many are still in use today and are very popular with collectors and restorers.
In 1921 the first experimental Model D's were produced. These tractors were sold to farmers and closely watched by engineers and officials of John Deere company.
After a few minor changes, the first production Model D, serial no. 3040, was built on May 30, 1923. The first 50 units have 4 holes in the steering wheel spokes and 4 holes cast in the radiator sides. They had fabricated front axles, a 26 inch flywheel and had a one piece steering rod mounted on the left side. A problem arose with the 26 inch flywheel. When the tractor was turned to the far left, and the front axle was at its highest point on the left, the left front wheel would hit the flywheel sometimes causing breakage.
There were 880, 26 inch Spoker D's produced and at serial no. 31280 the first 24 inch Spoker was produced. This corrected the flywheel from hitting the left front wheel. It was also the first 1925 Model D. The first 50 tractors made were considered 1923 models, serial no. 30401 thru 30450. Serial no. 30451 thru 31279 were considered 1924 models and serial no. 31280 thru 35208 were considered 1925 models.
The Model D serial no. 30401 was first tested in Nebraska on July 10, 1923. These tractors were also known as John Deere 15-27's.
Not only was the 24 inch flywheel different on the 1925 model, the main case was different to accomodate a P.T.O. It also had a 2 piece steering rod.
The first 940 Model D's of 1926 were also Spoker D's with the exception of serial no. 35891. This was the first Model D with a solid flywheel. This tractor is in a collection in Nebraska today. There were only 5846 Spoker D's produced, and the last one was built on Dec. 28, 1925.
The solid flywheel D's of 1926 and 1927 had keyed flywheels to the crankshaft, same as the spokers. In late 1927, the first block change occurred at serial no. 53388. The bore changed from 6 1/2 to 6 3/4 inches, but still used the same cylinder head.
In late 1927 a splined crankshaft and splined flywheel, replacing the keyed crankshaft and flywheel. At serial no. 49737, the Model D got a new fender design and a steel operator's platform. All previous models had a wooden operator's platform. In late 1928 the fuel tanks were changed at serial no. 68880. The fuel tanks then stayed the same thru the 1930 models, ending at serial no. 109943.
In 1927 the front wheels changed to square spokes, made by F&H Company. John Deere Company also made some flat spoke front wheels for the 1929 models. These were the rarest of the 1929's, however, both of these versions were discontinued in late 1929 and round spoke front wheels were once again used. Model D's then stayed the same thru 1930 models. 1929 was the largest production year, in their 31 years span, with 23,806 units being produced.
In 1928, 96 experimental Exhibit "A" D's were built. These D's had major engine changes. Horsepower was increased to 40 horsepower, they had 3 speed transmissions, P.T.O. mounted inside the main case, timken bearings, larger fuel tank and drag link steering. These tracdtors can be identified easily by their serial numbers since they all started with an X, the first was serial no. X67501, and the last was X67596. In July 1930, 50 more units were built. These were known as Exhibit "B" D's. Serial numbers started with B107001 and ended with B107050. Some of the changes from the Exhibit "A" tractors were engine RPM raised from 800 to 900, smaller diameter and wider belt pulley, new dust cover on pulley, 4 bolt main bearings, larger air cleaners and the first Model D's to have an upright exhaust stack. Some of these experimented with tracks in place of rear wheels, but this proved to be unsatisfactory.
1931 saw the largest change in the production of Model D's. They got new cyhlinder blocks, new cylinder heads, steering was moved from the left side to the right side of the tractor, drag link steering, upright exhaust stack, round fuel caps, 4 bolt main bearings, main case changed to accomodate the P.T.O inside it, longer clutch handle, and smaller diameter and wider belt pulley with new style dust cover. Petcocks were moved from the top to the side of the block, and engine horspower was increased to 40 at 900 RPM. They did not install the 3 speed transmission due to its extra cost. These tractors were built from 1931 thru 1934. Due to the depression and increased number of sales of the John Deere GP tractors only 9,146 were built. Serial no. 109944 was the first one in 1931, of 5533 being built.
There were so many tractors left over in 1931 (some didn't get sold until the fall of 1932) that only 188 Model D's were built in 1932. This was the lowest production year of the Model D.
In 1934 the fuel tank was changed again on the Model D. The flat back was discontinued and the new bubble type gasoline starting tank was first used. It also had the letters "Model D" silkscreened on the tank. 1935 saw the next major change in the Model D's. The oil filter and oil pump were moved to the bottom of the oil sump and the 3 speed transmission was introduced on a production Model D tractor. Late 1935 saw the loss of the brass carberator and a new axle design was introduced. Also more splines and 2 bolt end cap replaced the screw on the cap that had been used on all previous Model D tractors.
1937 saw another change. The lever lock inside the brake was discontinued and replaced by the pulley and band type on the left outside of the transmission with a brake pedal on the right side to lock and activate the brake. Front shutters were controlled from the operator platform.
Industrial Model D's began in 1925, but were only an Ag version with solid rubber tires and a faster gear ratio. This was accomplished by changing the rear axle sprockets from 39 to 28 teeth. Some of these tractors were used on the Hawkeye Motor Grader. Some were equipped with dual rear wheels.
1935 saw the first DI tractor built. The first one was serial no. 120029. The serial numbers were Model D numbers and used the same tags as the Model D. There were, however, some changes in these tractors. They had heavier rear axle housings, heavier rear wheels with brake drums cast into the rear wheels. They also had turning brakes and a lever type handle to lock the brakes. The rear wheels had 600 pound weights attached. Only 100 of these DI's were built in the seven years they were made. The last DI built was serial no. 150118 on Feb. 24, 1941. None of the DI's were ever styled and they were painted yellow with black lettering. Approx. 24,700 1935 thru 1938 models were built.
Next and last came the production of the styled D's. Production began on Apr. 7, 1939 with serial no. 143800. The last 11 unstyled D's and first styled D's were shipped to Canada.
Not only did the styled D's get a new hood and grill, they also got a dash with guages, shutter control, and a fuel shut-off lever mounted there. Other changes included a new drawbar and fender design. Steel wheels were still standard equipment Rubber tires could be ordered, with 12.75x28 rear and 7.50x18 for the front.
In Nov. 1940, rubber tires became standard equipment and steels the option. Rear tire sizes changed to 13x30 at serial no. 150617.
F&H round spoke rear wheels were also sold by dealers that used rubber tires. These were primarily used to replace steel wheels and were light enough to change in the field from steel to rubber and vice versa.
On tractors wtih rubber tires, round spoke wheels were standard until 1944. After that disk type front wheels were used and became standard equipment.
Starter, lights and P.T.O were options on all styled Model D's. In later production a live hydraulic system and front axle with offset holes were offered as options. A dealer installed gasoline conversion was also available. All these options held true right up to and thru the last 92 Model D's produced.
In early 1953 the factory shut down the assembly line for the Model D, however orders were still coming in for new ones. The assembly line was then set up in the street behind the factory to build a few more. The remaining parts were used to produce 92 more tractors in June and July 1953. These tractors became known as Streeter D's because of being built in the street. Production ended with serial no. 191670 and shipped Mar. 19, 1954. This was not the last tractor to ship out of the factory. The last one shipped Apr. 1954.
When production ended, 47,870 Styled D's had been built. The Model D's production life extended to over 30 years, from 1923 thru 1953 with 157,258 units built. This is the longest production of any John Deere tractor starting with the first experiment in 1917.