It is true that the demand for new buses fell off sharply after 1949, but I maintain that the poor reputation of the engine did contribute to the decline of the Crossley Motors company, particularly in the double deck field.
Somewhat surprisingly, since Crossley had not been a significant player in the pre war coach market, the single deck SD42 sold quite well to independent coach firms, whose operations were less punishing than all day stop start work on heavily laden municipal bus routes, and whose drivers tended to be rather more respectful towards their machinery.
Despite its premium prices, the Armstrong-Saurer range earned a solid reputation with hauliers for quality, but sales were a struggle in the depressed 1930s.
Crossley were totally dependent on the shrunken bus market, and that is why they failed.
The Crossley DD/SD42 was a very sound chassis design, but quickly revealed deficiencies in the engine department and in its steering, which was very heavy.
I found three old vehicles in there, two complete and one being just a chassis, with Armstrong-Saurer on it. I reported them all to a vehicle preservation organisation and six months later, all were gone, but to where?
So Saurer vehicles were made here on Tyneside for a period, from 1930-1937, according to Grace’s Guide.
Despite official denials, these proved to be well founded, and the entire Armstrong-Saurer range was withdrawn in 1937 when the Admiralty bought the Scotswood works and leased them back to Vickers-Armstrongs in order to concentrate on military work in the rapidly worsening political climate of the period.