The picture to the left shows the 185-B platform with 186-B stake racks. The platform was designed for the 1931 parallel framed AA157. This “Midland Steel Products Company” supplied platform cargo body was sold by Ford for their production of AA157 platform, stake, and stock trucks beginning in January 1931 and ended February 1932. The single or optional-dual wheeled AA157 with either a closed and open cab was used in combinations to form platform trucks. The 185-B platform had a 1-5/16” lower profile and a cargo area which was 7” wider and 34-1/2” longer than the 88-A platform.
Starting in March 1931 a new AA131 platform body (type 187-A) was released. It was a short version of the 185-B platform. In March 1932, BB truck production began. The sills for both the 185-B and 187-A platforms were modified to fit the new BB chassis but otherwise the bodies were unchanged.
According to the book “Ford Trucks Since 1905”, the 1933 platforms had a larger 82” wide cargo area. The cargo area lengths were 142” and 106” for types BB-186 and BB-187 respectively. These platforms had physical lengths of 12′ and 9′. The 1933 sized platforms continued as the production standard through 1937.
The 1931 185-B platform consisted of a wooden cargo floor attached to a stamped steel support structure. This structure was attached to wooden floor side sill assemblies which rested on the parallel frame. Excluding front external stake pockets, the overall body dimensions were 80-3/8” wide by 135-1/2” long. It was 11-9/16” from the bottom of the floor side sills to the top of the cargo floor boards. With stake racks or stock racks installed, the usable cargo floor was 75” wide by 132” long.
The cargo floor consisted of ten 1-1/4” thick floor boards with nine skid strips which were used to bolt the boards to a stamped steel support structure. This structure was attached to wooden floor side sills using angles. The body was installed on the frame with brackets and u-bolts.
The platform was completely assembled before being painting the same color as the cab. Consequently, the body was painted as a unit, including floor boards and fasteners.
An article containing the 185-B platform details is provided in the link below. This article is a PDF file (fairly large and therefore take some time to open).
186-B stake racks and 238-A stock racks (under construction)