Question 209General Subjects - Assistant Engineer

The correct answer is D) a special petroleum solvent. New piping and tubing for a hydraulic system should be degreased using a special petroleum solvent, as this is the safest and most effective method. Other options like alcohol, carbon tetrachloride, or water-based detergents are not recommended for degreasing hydraulic components, as they may damage or leave residues that could interfere with the proper functioning of the hydraulic system. Petroleum solvents are specifically formulated to effectively remove grease and oil without harming the materials used in hydraulic systems.