Page 82 - WHITE BOOK

Overview of Degradation Process of Power Steering Fluids
Power Steering fluid (P/SF) is the life blood of the hydraulic system that steers the vehicle’s wheels. This system is typically composed of an engine-driven pump, hydraulic cylinder, valves, hoses, and a gear assembly. The fluid (mineral, synthetic or ATF) and its additive package must provide low compressibility, conditioners and foam inhibitors, pump lubricity, and corrosion protection.
Today’s smaller rack-and-pinion systems operate in up to 2,500 psi. This raises the normal operating temperature of the fluid to about 178°F. Additionally, modern engine bays are tightly packed; restricted airflow concentrates heat on this system.
A key measure of P/SF degradation is ‘Additive Depletion’. Loss of the antioxidant additive increases, corrosion, particulate contamination, and viscosity. This stresses seals and hoses, causes components (pump, rack-and-pinion) to work harder, which leads to premature failure.
Testing all variations of P/SF for ‘Additive Depletion’ is quick, simple, and accurate using Fluid Rx Diagnostics’ Radial Planar Chromatographic analysis process:
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