The performance of brake system is dependent on the interaction between brake pad and rotor at the friction interface. The mechanical properties of the brake rotor that is made of gray cast iron are directly influenced by composition and microstructure. The elasticity modulus and the damping capacity play a significant role on the propensity of the brake rotor to generate noise. Brake squeal propensity was studied by investigating the correlation between the microstructure of gray iron brake rotor and the carbon equivalent (CE). The gray iron samples were manufactured to have different microstructures by changing the carbon equivalent (C.E.). The squeal noise tests were performed with different C.E rotors. The test results show potential of the high carbon composite rotor material to reduce the squeal noise propensity. In order to understand the effect of rotor microstructure and composition on squeal, resonant frequencies and damping ratios were evaluated. Coefficient of friction was also evaluated, however, this has already been studied with various rotor microstructures and carbon equivalent.