Mason Trucks

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The Mason Road King was the truck line of Durant Motors. Durant added the Mason Motor Truck Company of Flint, Michigan to his new company, and Mason Road King “speed trucks” were built at the Flint plant from 1922 to 1925, with production directed by the Locomobile arm of Durant Motors. Every model used a four-cylinder Herschell-Spillman engine. The Road King came as a 1-ton or 1½-ton chassis on a 130 or 150 inch wheelbase, and the heavier Model C was a 2½-ton chassis on a 168 inch wheelbase, built stout enough for bus bodies.

On this page: Road King · Custom bodies · Model C · Sales literature · Known trucks

Mason Road King (1 and 1½ ton)

Mason sold the Road King as a fast, durable light truck, available in two chassis lengths with an extra-large radiator. Specifications for 1924:

• Engine: 4-cylinder L-head cast en bloc, bore 4 in., stroke 5 in., 25.6 N.A.C.C. (46 maximum) horsepower; removable head, enclosed valves
• Lubrication: force feed by gear pump, bayonet oil gauge
• Cooling: water pump, extra-large radiator, wide fan belt with hand adjustment
• Fuel: 10½ gallon round tank on the dash, gravity feed; Johnson carburetor
• Clutch: duplex, 10 in. discs, removable without disturbing engine or transmission
• Transmission: sliding selective, three speeds and reverse; shaft drive with double universal joints and spring-cushioned torque arm
• Axles: drop-forged I-beam front axle; full-floating Mason rear axle with spiral bevel gears; Gilliam tapered roller bearings
• Brakes: 2¾ x 14 in. external service brake (foot) and internal emergency brake (hand)
• Springs: semi-elliptic, 38 x 2 in. front, 40 x 2½ in. rear
• Wheels and tires: heavy-duty artillery wheels, demountable rims, 34 x 5 pneumatic cord tires
• Wheelbase: 130 or 150 in.; tread 56 in.
• Weight: 130 in. chassis with hood and fenders, 2,950 lb
• Frame length behind the dash: 131¼ in. (130 in. chassis) or 176 in. (150 in. chassis); width 66 in.
• Electrics: Auto-Lite starting, lighting and ignition, Bendix starter drive
• Standard equipment: electric starter and lights, battery, speedometer, ammeter, electric horn, radiator guard, front bumper, tools, pump and jack

Changes for 1925

• Zenith carburetor in place of the Johnson
• 12 in. Borg & Beck dry-disc clutch
• Oil gauge added to the dash
• Channel-steel frame, 5-9/16 in. deep, with a riveted reinforcing angle carrying all body bolts
• Auxiliary rear springs; rear springs 48 in. long on the 150 in. chassis
• Molybdenum steel axle shafts with ten splines; artillery or disc wheels
• 32 x 6 pneumatic cord truck tires
• Chassis weight 3,142 lb (130 in.) or 3,377 lb (150 in.)

Custom built bodies

Mason offered the Road King with a range of custom bodies: combination stake, high front stake, full stake with sign boards, heavy duty beef and provision, open express, open express with slat rack, dump with wood hydraulic hoist, panel side express, full panel, six-post top express and six-post top screen. Click a picture to enlarge it.

Mason Model C (2½ ton)

The Model C was the heavy chassis of the line, designed “extra-heavy throughout for bus requirements.” Specifications for 1925:

• Engine: 4-cylinder L-head, bore 4 in., stroke 5 in., 25.6 N.A.C.C. (46 maximum) horsepower, Lynite pistons and connecting rods
• Lubrication: pressure feed to the main bearings, gear-type oil pump
• Cooling: water pump, 8 gallon radiator
• Fuel: 25 gallon tank on the left frame rail, vacuum feed, dash gasoline gauge; Zenith carburetor
• Clutch: 12 in. Borg & Beck
• Transmission: constant-mesh selective three-speed, midship mounted (ratios 4, 2 and 1 to 1)
• Axles: reverse Elliot drop-forged front axle with inclined king pins on ball thrust bearings; heavy rear axle with spiral bevel gears, 5.3 to 1
• Frame: pressed steel, 5-9/16 x 1¾ x 3/16 in., with riveted body outriggers
• Brakes: 2¾ x 16 in. external service brake and internal emergency brake
• Chassis lubrication: Zerk high-pressure system
• Wheels and tires: disc wheels on 20 in. rims, duals at the rear, 30 x 5 bus-type pneumatic cords
• Wheelbase: 168 in.; tread 56 in.; frame 193 in. behind the dash
• Weight: complete chassis, 3,900 lb
• Electrics: Auto-Lite, 6-volt battery ignition

Sales literature

Mason literature known to the club. No 1922 or 1923 pieces are known; if you have one, please let us know.

Known surviving trucks

1924 Mason fire truck, Richmond Hill, Ontario

The Richmond Hill, Ontario fire brigade bought this Mason new from the Mills & Hadwin agency of Toronto, and it served as a hose truck into the late 1940s. A local paving company later acquired it, and it ended up at a children’s summer camp. In the late 1990s the fire department got it back and volunteers restored it in its original red.

Do you own a Mason, or know of one? Please contact one of our technical advisors so it can be added here.

Related pages

• Locomobile, the Durant Motors division that directed Mason production
• Rugby, including Star and Rugby light trucks
• Star Truck Serial Numbers
• All makes in the Durant family

Sources: Mason sales literature, 1924 and 1925; Durant Family Registry, Durant’s Standard vol. 6 no. 2; club registry records.