A quick search through some Chevy Shop and Parts Books (late 1930's-50's) indicate that is the anchor point for a Parking brake pivot plate pull back spring for trucks with pedal operated parking brakes and cars with torque tubes. Just a SWAG, but I think it was probably placed on all torque tubes as a standard construction feature, used when needed and unused when not. Just my thoughts on the subject.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
