MAZ-6422

MAZ-6422 at a glance

In the late 1970s MAZ decided to build a heavy truck family in the Western style, for long-distance freight and to replace the outdated 500 series. According to the old 1cars text, the new trucks drew on several prototype and transitional models, including the MAZ-5336 and the MAZ-6301/6302, and on the MAZ-515 tractor. The Minsk plant's story is told in the history of MAZ.

From prototypes to the one-millionth truck

Series production started on 19 May 1981, and the 1,000th truck of the new family followed in April 1983. From 1985 East Germany imported the MAZ-6422 and the lighter MAZ-5432 for long-haul transport. On 14 April 1989 the plant built its one-millionth truck, a MAZ-6422. In the same year the more powerful MAZ-64221 and MAZ-64224 arrived with the new YaMZ-8421 and YaMZ-8424 engines.

By the 1990s the cab and engines no longer met the rules for international long-haul work, especially in Western Europe. MAZ developed the MAZ-6430 as the successor, and the two models were built in parallel in Minsk from 1997.

Cab and comfort

The new cab broke with the rounded shapes of the 1960s and 1970s. It has a one-piece panoramic windscreen instead of the split screen, headlights moved into a slimmer bumper and a roof spoiler to cut drag, according to the old 1cars text. Inside, the same source describes a sprung driver's seat and controls within easy reach. The horn moved to the steering wheel instead of a pull cord, the storage stays shut on rough roads, and two sleeping berths let two drivers take turns. The old text calls it one of the most comfortable truck cabs of the Soviet era.

Short-haul versions such as the MAZ-64229-032 have a three-seat day cab without a berth.

Engines and gearboxes by version

Torque figures for the YaMZ-8421, 8424 and the MAN unit come from the old 1cars text. The YaMZ V8s are turbocharged 90-degree engines; the MAN-engined MAZ-64226 was the only version with a Western engine. The old 1cars text gives fuel use of about 33 l/100 km on the motorway and 45.5 l/100 km in mixed driving.

Gearboxes are manual. The YaMZ-238A and YaMZ-2381 have eight forward speeds. According to the old 1cars text, the 64224 used a YaMZ-239 or a 12JS200TA gearbox with nine forward speeds, and a ZF 16S 151 was also listed for the range. The clutch is a twin dry-plate unit.

Final drives and cold-weather equipment

Each version was matched to its work by the rear-axle ratio. According to the old 1cars text, the MAZ-64229 used a final drive of 5.49:1 (4.73:1 as an option), the more powerful MAZ-64221 6.59:1 or 5.49:1 for heavy road trains, the MAZ-64224 a long 3.97:1 for faster long-distance work, and the MAN-engined MAZ-64226 4.73:1. A lower ratio means less engine speed at cruising pace and lower fuel use; a higher one gives more pulling power when starting a heavy train on a hill.

For cold climates, the same source lists a fuel-fired pre-heater that warms the engine before a start and can also heat the cab during rest stops, a useful feature on trucks with sleeper berths. The V8 engines use closed injectors and dry air filters.

MAZ-64229 specifications in metric and imperial units

Versions and derivatives

How the MAZ-6422 compares

Compared with the MAZ-500-based tractors it replaced, the 6422 offered a sleeper cab, a 42-tonne train weight and 84% more power in its base form: 243 kW against 132 kW for the YaMZ-236 of the MAZ-500 family. Against Western tractors such as the Volvo FH launched in 1993, it was thirstier and simpler inside, which is why MAZ developed the 6430. In our ranking of the most powerful trucks the MAZ-6422 is ranked #9, just behind the MAZ-6430 at #7.

For lighter work MAZ also built rigid trucks and chassis such as the MAZ-5334, while all Minsk models are on the MAZ brand page.

Buying and preserving a MAZ-6422 today

Our verdict: the MAZ-6422 is a robust, repairable heavy tractor for regional haulage and a sought-after piece of transport history for collectors of Eastern European trucks. For work, a later 64221 or 64224 with a well-maintained YaMZ-8421/8424 offers the best pulling power; for preservation, an early 1980s 6422 with its original cab is the most interesting.

What to check:

• the frame, the fifth wheel and the rear bogie mountings for cracks;
• the YaMZ V8 for smoke, coolant loss and turbocharger wear;
• the gearbox, especially range changes on the YaMZ-239, and the twin-plate clutch;
• the air brakes and the cab tilt mechanism;
• cab corrosion around the windscreen and steps.