Donaldson - P171873 - Hydraulic Filter

This hydraulic filter element removes particulate contamination from the hydraulic system’s return flow before the fluid re-enters the reservoir. It is installed in the filter head mounted on the hydraulic system circuit; trapped debris protects downstream components such as the pump and control valves from abrasive wear. A clogged element forces the bypass valve to open, allowing unfiltered oil to circulate, which accelerates internal component wear. The manufacturer’s design matches the housing’s seal groove and bypass-valve cracking pressure, ensuring the element seats correctly and the bypass opens only at the intended differential pressure. When replacing, clean the housing interior and replace the seal ring before torquing the filter head to specification.