Berliet started fitting air-operated power steering standard on the heavy models (19 tonnes and more) in 1950 with the GLM 10. Only the smaller GLC (12 tonnes) and GLR (16 tonnes) had to wait the M2 version in 1961 to get an hydraulic steering. More surprising, Renault’s heavy range (15 tonnes and over) had air-operated power steering from 1934. Just think trucks like the standard Mack B61 6x4 were basicly offered with elbow-grease steering as late as 1966… I even think that some British 8-wheelers or long-distance tractors had it optional in the late sixties too.