B ulldozers are widely used in the coal mining industry for leveling, tidying, and pushing the excavated coal. The reliability of bulldozers is supported by the performance of the hydraulic system. The hydraulic system in a bulldozer is present in the drive system of the bulldozer\\\'s blade. Analysis of the circuit and components of the bulldozer represents an in-depth study of the hydraulic system\\\'s performance in this heavy machinery. The hydraulic system in a bulldozer plays a crucial role in operating various components such as the blade and ripper, allowing the unit to perform its tasks with high efficiency. This proposal includes a thorough review of the hydraulic circuit, hydraulic components such as the hydraulic pump, hydraulic cylinder, hydraulic valve, hydraulic fluid, and others that form the hydraulic system in the bulldozer. Performance analysis includes the evaluation of hydraulic pressure, fluid flow, and component power. In preparing this analysis, the author refers to scientific literature, including the official manuals from the Komatsu bulldozer manufacturer, technical books on hydraulics, as well as research results and scientific papers related to mechanical engineering. This analysis aims to understand how the hydraulic circuit of the blade cylinder works and the damage that significantly affects the performance of the Komatsu D155A-6 bulldozer. The results of this analysis provide in-depth insights into the performance of the bulldozer\\\'s hydraulic system, enabling a better understanding of the crucial role this system plays in achieving operational efficiency and maximum performance of the construction machinery.