1951 model-year was the year for Chevrolet 1/2 ton brake changed to Duo-Servo single anchor type (Bendix, not Huck.
http://chevy.oldcarmanualproject.com/chevyresto/51134.htm

The 1952 specs manual still shows Huck in larger trucks in 1952.
http://chevy.oldcarmanualproject.com/chevyresto/52138.html

Model year and calendar year might not coincide - model year might have changed before the end of the previous calendar year (1953 model year starting in late 1952, for example). Also, old style brake equipment might have been installed until it ran out?

Most likely, the change to Bendix brakes in 3/4 ton and larger came in 1953 model year?



Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.