When performing a brake job on your 1974 Chevrolet Corvette, the condition of the brake rotors must be checked as well. There are three important specifications to check on the rotor: rotor nominal thickness, rotor minimal machining and rotor discard thickness
Rotor Nominal Thickness
The rotor nominal thickness is simply the thickness of the rotor's disk when brand new. This becomes important when replacing the rotors, as you need to measure the replacement rotor to make certain it will fit. A 1974 Corvette's rotors have a 1.25-inch nominal thickness.
Rotor Minimal Machining
The minimal machining of a brake rotor is the thinnest the rotor's disk may be and still allow for machining or resurfacing. When the rotor measures below this specification, it must either be replaced or reused without machining. The 1974 Corvette's rotors have a minimal machining measurement of 1.23 inches.
Rotor Discard Thickness
The rotor discard thickness is the thinnest the rotors disk may measure before needing to be replaced. On a 1974 Corvette, If rotors are reused when below 1.215 inches, damage to other braking components may occur.
