51-55 Bendix brakes were not self-adjusting.

From what you describe, your brake assembly has been changed (although, you might have a late 1950 truck that has the 1951 Bendix brakes)? The possibilities are myriad - can you post a link to some photos?

Do your brakes look like these earlier (1947-1950) Huck brakes;
or,
Do you brakes look like these 1951-55 Bendix brakes?

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.