Hummel A

The air-cooled two-cylinder diesel engine has a displacement of 1,005 cc and produces 20 hp. At an unladen weight of 1,050 kilograms, this is a light, compact tractor whose power was sufficient for smaller plots, trailer work and driving mounted implements through the power take-off.

Tractors of this class fall under driving licence category T; the power take-off on such machines runs at the standard speed of 540 or 1,000 rpm, so that mounted implements fit regardless of manufacturer. The air-cooled engine needs no radiator, water pump or antifreeze, making it robust against frost and simple to maintain.

When buying such an old two-cylinder machine, it is worth checking the cooling fins on the cylinder and head, which should be free of oily, caked deposits, as well as compression and smoke behaviour on a cold start. Bearings on the front axle and steering, the condition of the clutch and the tightness of the injection pump also belong in the inspection. The steering box and front axle bushings deserve a look too, since a machine this old and this rare can be hard to source replacement parts for.