

The firstCadillac automobiles were the 1903 Model built in the last quarter of 1902. These were 2-seater "horseless carriages" powered by a reliable and sturdy 10 hp (7 kW)single-cylinder engine developed byAlanson Partridge Brush and built byLeland and Faulconer Manufacturing Company of Detroit, of whichHenry Leland was founder, vice-president and general manager.
Reformed as theCadillac Automobile Company in August 1902, it began manufacturing the runabouts and named them "Cadillac" after the city's founder Antoine Laumet, the self-styledAntoine Laumet de La Mothe, sieur de Cadillac at the re-purposedDetroit Assembly. The 1904 Model B was a refinement of the 1903 and while still a mid-engined, one cylinder automobile, it now had an extended front and transverse front suspension. With the introduction of the Model B, the 1903 style became known as the Model A . Both the Model A and B were available as a two-passenger runabout or four passenger rear tonneau. Catalogs also show a light delivery.
The one cylinder Cadillac continued to be offered through 1908 in the runabout, tonneau or delivery bodies under a variety of Model designations which are delineated below.
The Models A, B, C, E, and F shared a single-cylinder 98.2 cu in (1,609 cc) engine rated from 6.5 to around 9 hp (7 kW) depending on model. The cylinder was horizontal, pointing rearward, and was cast from iron with a copper water jacket. Bore and stroke were square at 5 in (130 mm). The engine was named by its manufacturers, Leland and Faulconer, "Little Hercules".
The engine employed a patentedvariable-lift intake valve licensed fromAlanson Partridge Brush.[1] The restrictions of this design using Brush's patents led the company to develop their own four-cylinder engine for the laterModels D, L, G, and H.
When the street was muddy or dirty the car would be backed up to the sidewalk so tonneau passengers did not need to walk in the mud.

Three cars were completed in time for theNew York Auto Show staged in January, 1903. All three cars were sold at the show and by mid-week orders had been taken for 2,286 further units, each one requiring a deposit of US$10 ($350 in 2024 dollars[2]). The cars had some similarities to theFord Model A; however, the Cadillac was designed by Alanson Partridge Brush.
Throughout 1903, 2,497 units were built.[3] Production began in March 1903 and output totalled 1,895 units from March 1903 to March 1904. The 2-seaterrunabout cost US$750 ($26,247 in 2024 dollars[2]); an optional rear entrance detachabletonneau cost $100 and doubled the occupant capacity. The entire body was bolted to the chassis and could be lifted without removing or disconnecting any plumbing or wiring.[4]
Cadillacs of 1903 sometimes are identified erroneously as the Model A; in fact, they were known simply as the "Cadillac Runabout" and the "Cadillac Tonneau". When a new Cadillac was introduced in 1904, it was designated the "Model B"; meanwhile, production of the earlier runabout andtonneau models continued through a second year. Only at that time didCadillac began to designate them asModel A cars to distinguish them from the new, 1904 models.
The front of the car had a sloping, curved, false hood and radiator. The car was advertised as having6+1⁄2 horsepower (4.8 kW). Power was transmitted the rear wheels by chain-drive through a planetary transmission. Pedal operated brakes on rear axles were supplemented by engaging reverse gear. The 22-inch wood wheels had 12 spokes and the car's wheelbase was 72 in (1,800 mm).[5]

The Cadillac earned a reputation for reliability, ease and economy of maintenance and for being a car with a remarkable ability for climbing and pulling. In 1903, F. S. Bennett, Cadillac's importer into the UK, entered the car in the Sunrising Hill Climb, where it was the only single-cylinder car to finish, and in the 1,000 Miles Reliability Trial, where it came fourth in its price class in overall points but first in its class in points scored for reliability.[5]
Production continued into 1904 but with an8+1⁄4 horsepower (6.2 kW) engine. A pressure-fed multiple oiler was added.


Introduced in January 1904 Cadillac'sModel B was similar to their Model A, sharing its engine but using a pressed-steel frame and axles and the Model B was on a longer 76 in (1,930 mm) wheelbase. The front axle is described as girder-style. It supported the car through a single transverse half-elliptic spring.[6] The sloping dash was replaced by a detachable box-like front to the body and a vertical radiator. All body styles lost as much as 70 pounds weight. Prices went up $50.[6] The car was advertised as having8+1⁄4 horsepower (6.2 kW) but there were no changes to the design of the engine.[6]
The Model B was available as a runabout or atouring car with a detachable rear-entrancetonneau and optionalsurrey top, or with a delivery body. The passenger cars were both priced at $900 and weighed roughly 1,450 lb (658 kg). Options now included a bulb horn and a deck to replace the tonneau. The Model B continued in production through 1905 when an alternative tubular front axle was available and the power was advertised as 9 hp (6.7 kW).[6]

TheModel C was a short-wheelbase car intended to replace the old Models A and B for the summer of 1905. It shared much of the Model B chassis components, but used the hood and radiator of the Model F. Thetonneau was detachable, unlike the Model F.
Riding on a 72 in (1,800 mm) wheelbase, Model C was available as either a runabout, priced at $750, or touring car, priced at $850, with a detachable rear-entrance tonneau and optional surrey top. The lightweight runabout weighed just 1,330 lb (600 kg), 120 pounds (54 kg) less than the touring model.
Four cylinder engine, see separate articleCadillac Model D

TheModel E was released in January, 1905. It was a featherweight 1,100 lb (500 kg) runabout model with seating for two, priced at $750 in 1905. It used a 74 in (1,900 mm) wheelbase, splitting the difference between the C and the B/F.
No detachable tonneau to make it a four-seater was available. The arched front axle was tubular. The axle was given a truss and added mid-year was a rocker shaft between it and the spring. Single cylinder 98.2 cu in (1,609 cc) engine with an advertised output of 9 horsepower. The planetary transmission which had balanced linkage on its bands provided two speeds and reverse. Drive was taken to the back axle by chain.
One of the first closed-body coupes was first built using a Model E, called theCadillac Osceola, at the C. R. Wilson Company. The Osceola was requested by Mr. Leland to determine the feasibility of a car body that was closed to the elements, and the construction was supervised by Fred J. Fischer, who, withCharles T. Fisher and his other brothers, later foundedFisher Body.[7] Named for a Seminole Indian Chief whom Henry Leland admired, theOsceola remained with the Leland family for years.

TheModel F was the primary new Cadillac model of 1905. It had a sharper hood and radiator, prompting the update of the Model B (which became the Model C) and even spawning an aftermarket of updates to existing Model A and Model B cars. Models E and F shared the same chassis, though the latter was lengthened by two inches
The Model F was available as either a 4-seater 2-doortouring car with side-entrance to the fixed tonneau or a 2-seater delivery vehicle. Both were priced at $950 in 1905. The Model F shared the same 76 in (1,900 mm) wheelbase as had been used on the Model B.
Four cylinder engine, see separate articleCadillac Model D

Cadillac's single-cylinder lineup was consolidated into two models for 1906, the short wheelbaseModel K and long wheelbaseModel M. Priced at $750 for the Model K or $950 for the Model M, 3,650 units were sold that year. The K and M were essentially similar to the Models E and F from 1905 but with updated bodies. Production and sale of the Models K and M continued in 1907 in both the Tulip and straight lined body styles. The Model M was offered with a delivery body in 1906 and again for the 1907 model year.
Three 1907 Model Ks were used in the famousDewar Trophy test of theRoyal Automobile Club in England.[8] They were disassembled, the parts mixed, and then reassembled without problems. This test cemented the Cadillac's reputation for precision and quality and brought fame to the marque.
The Model M continued only as a commercial delivery vehicle for 1908, priced at US$950 ($32,059 in 2024 dollars[2]).

TheModel S andModel T of 1908 were essentially versions of the K/M from previous years with the wheelbase extended to 82 in (2,100 mm). These would be the last single-cylinder Cadillacs. For 1909 the lineup standardized on the four-cylinderModel Thirty. The main difference between the S and T was that the latter lackedrunning boards.