Willys MB

In short

• Built from 1941 to 1945 by Willys-Overland (MB) and Ford (GPW) to a single standard design; Willys made about 360,000 and Ford about 280,000.
• Willys L134 "Go Devil" inline-four of 134 cu in (2.2 l): 45 kW (60 hp) gross, 40 kW (54 hp) net.
• Part-time four-wheel drive, three-speed gearbox with a two-range transfer case, live axles on leaf springs; 1,113 kg with fluids and fuel.
• Top speed 105 km/h (65 mph) and a range of about 480 km (300 miles) on 57 litres of fuel.

Willys MB at a glance

Development: Bantam, Ford and Willys

In June 1940 the US Army Quartermaster Corps issued its first specification for a light reconnaissance vehicle of about 1,200 lb (544 kg) with a payload of up to 600 lb (272 kg). On 11 July 1940 the Army sent formal requirements to 135 manufacturers, with bids due on 22 July. The winner had 49 days to build a prototype and 75 days to complete 70 test vehicles. The empty weight was first limited to about 1,275–1,300 lb and later raised to 2,160 lb (980 kg).

American Bantam delivered its Bantam Reconnaissance Car, designed by Harold Crist and Karl Probst, at 4:30 pm on 23 September 1940, half an hour before the deadline. The Army tested it at Camp Holabird from 27 September to 16 October 1940. That story is told in our article on the Bantam BRC-40. Ford answered with the Pygmy and the GP, whose tractor engine was tuned from 22 to 30 kW (30 to 40 bhp). Willys built the Quad, then the MA. Its 45 kW (60 hp) engine, designed by Delmar "Barney" Roos, impressed the soldiers who tested it.

In July 1941 Willys won a contract for 16,000 vehicles, mainly because of its engine and its lower price, and its design became the MB. Ford received orders for 30,000 in October 1941 and for 63,146 GPWs in December 1941. Roos's design patent 136819, assigned to Willys-Overland, covered the Jeep's front end.

Design and engineering

The MB is a small open vehicle for a crew of three or four. Its frame carries live axles on leaf springs front and rear. The engine drives through a three-speed gearbox and a two-range transfer case to a part-time four-wheel-drive system. It was designed to carry a .30 or .50 calibre gun on a post between the front seats. Height with the top up is 69¾ in (1,770 mm), and the vehicle can be lowered to 52 in (1,320 mm) for shipping.

The pressed-steel slat grille is one of the details collectors use to date a Jeep. Ford designed it, with nine vertical slots, and Willys adopted it after vehicle number 25,808. Both firms built the 1/4-ton Jeep to a single standard design. American Central Manufacturing (ACM) made about three-quarters of all the bodies.

Go Devil engine and drivetrain

The Willys L134 "Go Devil" is an inline-four of 134 cu in (2.2 litres). It gives 45 kW (60 hp) gross and 40 kW (54 hp) net. With 45 kW and 1,113 kg, the MB has about 40 kW per tonne. The power-to-weight calculator sets that against a modern off-roader.

Production and variants

Ford built its GPWs at five plants: River Rouge (21,559), Dallas (93,748), Louisville (93,364), Chester (18,533) and Edgewater (1,333). The total for the war is more than 647,925 Jeeps, including the early pre-production vehicles. Some early GPWs used Willys-design frames, and some late-1943 GPWs had unmodified Willys bodies.

In service

The Jeep became the main light vehicle of the US forces and their allies, replacing horses, mules and motorcycles in many roles. In his memoirs Dwight D. Eisenhower wrote that senior officers counted it among the five most vital pieces of equipment for success in Africa and Europe. George C. Marshall called it "America's greatest contribution to modern warfare".

Soldiers and depots adapted Jeeps in the field. They added gun mounts such as the M31 pedestal and M48 bracket, radio fittings, wire cutters, stretcher racks and deep-water fording kits. The MB served on through the Korean War. The M38 (Willys MC) of 1949 replaced it, then the M38A1 (MD) of 1952 and the Ford-designed M151 of 1960.

The Jeep name and the civilian CJ

Willys applied to register "Jeep" as a trademark on 13 February 1943, and the US Federal Trade Commission opened a case over its advertising on 6 May 1943. In 1948 the FTC ruled that Willys could not claim to have created the Jeep alone. The trademark was finally granted on 13 June 1950. In 2015 the Pennsylvania General Assembly passed a resolution crediting Bantam with inventing the Jeep.

Willys's first post-war product was the civilian CJ-2A of 1945, the world's first mass-produced civilian four-wheel-drive vehicle. The Jeep Station Wagon followed in 1946 and the Jeepster in 1948. Kaiser bought Willys-Overland in 1953 and renamed it Willys Motor Company, then Kaiser-Jeep in 1963, and American Motors bought it in 1970. The brand's later history is in our page on Jeep's history and landmark models, and today's descendant in our article on the Jeep Wrangler.

Preservation and collecting today

In 1991 the American Society of Mechanical Engineers named the MB an International Historic Mechanical Engineering Landmark. For collectors, the details that date and identify a Jeep come from the production story:

• Grille: Willys adopted Ford's pressed slat grille after vehicle 25,808, so the grille helps to place an MB in the production run.
• Maker: a Willys MB and a Ford GPW look almost the same, but some GPWs used Willys frames or bodies.
• Rarities: only 27 Willys MAs are known to exist, and four of the four-wheel-steering Ford GPs survive.

More vehicles of the decade are in the 1940s classics section, and other Willys models are in the Willys catalogue.