11. New piping and tubing to be installed in a hydraulic system can be safely degreased by using __________.

Special petroleum solvents are formulated to be compatible with hydraulic oil and system components, effectively cleaning without residue or seal damage. Hydraulic systems typically use petroleum-based oil, requiring compatible cleaning agents that avoid seal damage, corrosion, and water contamination. Carbon tetrachloride is toxic, alcohols can damage seals, and water-based detergents cause corrosion; therefore, a special petroleum solvent is the appropriate choice for degreasing hydraulic piping.