From my 48-51 Chev truck shop manual: Half-ton truck has 11 inch drums, front and rear; 3/4 ton has 12 inch rear drums, 11 inch front. Maximum size is .060" over for both. Your '50 model has 'Articulating Link' brakes with the anchor pin at the bottom; they look different from the 'Duo Servo' setup that is the later model system and has the adjuster at the bottom. The Duo Servo system was used in 1951 and later vehicles. I don't think your truck uses primary and secondary shoes- I'll have to look at the shop manual again. If you are honing the cylinders, the maximum size is +.004" for wheel cylinders; +.005" for the master cylinder, measured with a thin feeler gauge between the piston and cylinder bore- I don't think you can find brake cylinder gauges any more.
Harvester
