Human plays a vital role in the manufacturing process of a product during the planning, design, assembly, production, and maintenance phase. This paper presents a systematic method of determining the reliability and availability of an 8-step auto unit manufacturing system taking into consideration the case of occurring human error during maintenance. The whole process involves eight major units as Combustion engine, power train unit, fuel feed unit, fuel injection unit, drain or exhaust unit, engine cooling unit, brake unit, and body frame. With the failure of any of these units, the whole process can fail. Also, a constant failure rate and a general repair time are taken into the consideration for each operative unit that makes up the process. The integral differential equations were generated based on Markov modeling of the process and solution derived by considering repair time distribution using the Laplace transform. Calculations of different reliability aspects like process availability, mean time to failure steady-state nature, and profit analysis are done using supplementary variable technique and copula methodology.